{ "data": { "a": { "slug": "mandrill", "name": "Mailchimp Transactional (Mandrill)", "vendor": "Intuit Mailchimp", "vendorUrl": "https://mailchimp.com/features/transactional-email/", "kind": "http-api", "category": "email", "summary": "Transactional email service from Intuit Mailchimp, formerly Mandrill. It sends application email and SMS through an HTTP API, SMTP or a hosted MCP server, with templates, inbound routing, webhooks and reporting, as a paid add-on to a Mailchimp plan.", "url": "https://www.anchorterminal.com/tools/mandrill", "markdownUrl": "https://www.anchorterminal.com/tools/mandrill.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/mandrill.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/mandrill.json", "dns": "mandrill.grade.anchorterminal.com", "repo": "https://github.com/mailchimp/mailchimp-client-lib-codegen", "license": "Proprietary service under Mailchimp's Standard Terms of Use and Additional Terms. The client libraries are under Mailchimp's own client library licence agreement", "transports": [ "http" ], "remoteUrl": "https://mandrillapp.com/api/1.4", "packages": [ { "registry": "npm", "name": "@mailchimp/mailchimp_transactional" }, { "registry": "pypi", "name": "mailchimp-transactional" } ], "auth": "api-key", "authNotes": "Self-serve API key, created in the Transactional web app at mandrillapp.com/settings by an Owner or Admin of the Mailchimp account. The key goes in the JSON body of every POST as `key`, and the MCP server takes it as `Authorization: Bearer`. A key can be limited to chosen endpoints and to IP addresses, and a restricted key needs the AI Agents permission group to use the MCP server. Test keys work only in test mode. There is no OAuth for this API.", "pricing": "paid", "pricingNotes": "$20 per block of 25,000 emails a month for 1 to 20 blocks, falling in steps to $10 at 161 blocks or more, on top of a Standard or Premium Mailchimp marketing plan. Blocks are billed monthly in advance and unused emails do not roll over. A dedicated IP is $29.95 a month. An agent's owner can start without a contract through the demo, which gives 500 emails once to the account's own verified domain on any Mailchimp account, free plan included. Test keys send nothing and cost nothing (https://mailchimp.com/pricing/transactional-email/).", "priceSummary": "$29.95 / mo", "where": "hosted", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the developer docs, the OpenAPI file or the pricing page (checked 2026-10-08).", "endpoints": [] }, "toolCount": 9, "popularity": { "githubStars": null, "npmWeekly": 226039, "pypiWeekly": 132016, "asOf": "2026-10-08" }, "docsUrl": "https://mailchimp.com/developer/transactional/docs/fundamentals/", "llmsTxt": "https://mailchimp.com/developer/transactional/llms.txt", "openapi": "https://mailchimp.com/developer/openapi/api-reference-2.json", "capabilities": [ "email.send", "email.templates", "email.inbound", "email.domains", "email.analytics" ], "tags": [ "hosted", "paid", "mcp", "openapi", "llms-txt", "api-key", "smtp", "webhooks", "inbound", "sandbox", "typescript", "python", "status-page", "soc2" ], "lastRelease": "2026-03-24", "graded": true, "anchor": { "graded": true, "score": 61.5, "grade": "C", "agentReady": false, "rank": 610, "ranked": true, "rankOf": 1510, "categoryRank": 15, "methodology": "0.7", "run": "2026-10-01", "scores": { "ergonomics": 60, "maintenance": 28, "payments": 35, "reliability": 70, "schema": 79, "security": 68, "transparency": 71 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-11-04" }, "negative": 0, "verdict": "A public OpenAPI 3.1 file covers all 99 operations, the docs serve Markdown and llms.txt, and keys can be limited by endpoint and IP address. Sending needs a Standard or Premium Mailchimp plan plus $20 blocks of 25,000 emails. No send idempotency key or SLA was found, and the newest dated release is from 24 March 2026.", "bestFor": "Teams already paying for Mailchimp Standard or Premium that want transactional mail, inbound parsing and an MCP server on the same account.", "strengths": [ "OpenAPI 3.1 file for all 99 operations, with typed error bodies for 401, 402, 404, 422, 429 and 500", "Hosted MCP server at `https://mandrillapp.com/mcp` with 9 tools, three of which list, describe and call API endpoints", "API keys can be limited to named endpoints and to IP addresses, and test keys send nothing", "Every docs page has a Markdown copy at the same URL plus `.md`, with an llms.txt index", "Status page lists Mailchimp Transactional as its own component with month-by-month event history" ], "weaknesses": [ "Full use needs a Standard or Premium Mailchimp marketing plan in addition to the email blocks", "No idempotency key on `/messages/send`, and no `Retry-After` header found in the docs or the specification", "Three delivery-delay incidents in September 2026, two of them lasting more than four hours", "The newest client library and specification release is 24 March 2026, and the changelog's newest entry is 19 August 2025", "The docs give three API version paths (1.0, 1.3 and 1.4), and the llms.txt link to the OpenAPI file returns 404" ], "agentNotes": [ "Send every call as POST with the key in the JSON body as `key`. The MCP server takes the same key as `Authorization: Bearer`", "Use a test API key while building. Test sends are free, capped at 10,000 a day, and deliver nothing", "Verify the sending domain with DKIM and DMARC first. Mail from an unverified domain is rejected with the reason `unsigned`", "Keep `/messages/search` under 20 calls a minute and set `limit` (default 100, maximum 1,000). There is no offset, so use an activity export for more", "For a restricted key that must also use the MCP server, enable the AI Agents permission group on the key" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "C", "methodology": "0.7", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 61.5 } ], "editorialScores": { "ergonomics": 60, "maintenance": 28, "payments": 35, "reliability": 70, "schema": 79, "security": 68, "transparency": 64 }, "provenanceScore": 78, "checked": { "categories": { "ergonomics": "2026-11-04", "maintenance": "2026-11-04", "payments": "2026-11-04", "reliability": "2026-11-04", "schema": "2026-11-04", "security": "2026-11-04", "transparency": "2026-11-04" }, "last": "2026-11-04", "lastMoved": "2026-11-04", "oldest": "2026-11-04", "stale": false, "staleAfterDays": 90 } }, "connect": { "install": "npm install @mailchimp/mailchimp_transactional", "http": "curl -sS -X POST \"https://mandrillapp.com/api/1.0/users/ping\" \\\n --header 'Content-Type: application/json' \\\n --data-raw '{ \"key\": \"YOUR_API_KEY\" }'", "claudeCode": "claude mcp add --transport http mctx-mcp https://mandrillapp.com/mcp \\\n -H \"Authorization: Bearer YOUR_API_KEY\"", "config": { "mcpServers": { "mctx-mcp": { "headers": { "Authorization": "Bearer YOUR_API_KEY" }, "type": "http", "url": "https://mandrillapp.com/mcp" } } } }, "letme": { "capability": "https://letme.dev/email.send", "tool": "https://letme.dev/mandrill" }, "sameCompany": [ "mailchimp-marketing" ], "area": "communication", "unitPrices": [ { "item": "Email block, 1 to 20 blocks", "unit": "1k-emails", "usd": 0.8, "note": "$20 per block of 25,000 emails, billed monthly, unused emails do not roll over. Needs a Standard or Premium Mailchimp plan" }, { "item": "Email block, 21 to 40 blocks", "unit": "1k-emails", "usd": 0.72, "note": "$18 per block of 25,000" }, { "item": "Email block, 41 to 80 blocks", "unit": "1k-emails", "usd": 0.64, "note": "$16 per block of 25,000" }, { "item": "Email block, 81 to 120 blocks", "unit": "1k-emails", "usd": 0.56, "note": "$14 per block of 25,000" }, { "item": "Email block, 121 to 160 blocks", "unit": "1k-emails", "usd": 0.48, "note": "$12 per block of 25,000" }, { "item": "Email block, 161 blocks or more", "unit": "1k-emails", "usd": 0.4, "note": "$10 per block of 25,000" }, { "item": "Dedicated IP", "unit": "month", "usd": 29.95 } ], "provenance": { "legalEntity": "The Rocket Science Group LLC d/b/a Mailchimp", "domain": "mailchimp.com", "domainRegistered": "2001-06-29", "endpointOnVendorDomain": false, "terms": "https://mailchimp.com/legal/terms/", "privacy": "https://www.intuit.com/privacy/statement/", "statusPage": "https://status.mailchimp.com", "changelog": "https://mailchimp.com/developer/release-notes/", "securityTxt": "valid", "checked": "2026-10-08", "notes": [ "The Standard Terms of Use, updated and effective 10 October 2025, name The Rocket Science Group LLC d/b/a Mailchimp, 405 N Angier Ave. NE, Atlanta, Georgia, part of the Intuit group with Intuit Inc. as parent.", "Transactional Email is also governed by the section For Transactional Email (formerly Mandrill) of the Additional Terms at https://mailchimp.com/legal/additional-terms/, which the Standard Terms incorporate, and by the API Use Policy updated 1 August 2023.", "The privacy field points at the Intuit Global Privacy Statement, last updated 9 March 2026. Mailchimp's terms name it as the privacy document for the service, mailchimp.com/legal/privacy redirects to it, and it names The Rocket Science Group LLC d/b/a Mailchimp. Mailchimp publishes no separate privacy policy.", "The API and the MCP server are served from mandrillapp.com, registered 2011-09-01, not from mailchimp.com (RDAP, Verisign).", "mailchimp.com/.well-known/security.txt holds one Contact line that points at the responsible disclosure section of the security page, with no Expires field. mandrillapp.com has no security.txt (404).", "The changelog covers the Marketing and Transactional APIs together. Its newest entry is dated 19 August 2025." ], "score": 78 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/mandrill.json", "live": { "slug": "mandrill", "probe": { "target": "https://mandrillapp.com/api/1.4", "method": "get", "lastAt": "2026-11-07T22:56:07.717141563Z", "lastOk": true, "lastStatus": 404, "lastMs": 431, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 432, "p95ms24h": 501, "samples24h": 244, "samples30d": 7466, "days": [ { "date": "2026-10-08", "probes": 50, "ok": 50 }, { "date": "2026-10-09", "probes": 250, "ok": 250 }, { "date": "2026-10-10", "probes": 247, "ok": 247 }, { "date": "2026-10-11", "probes": 247, "ok": 247 }, { "date": "2026-10-12", "probes": 247, "ok": 247 }, { "date": "2026-10-13", "probes": 248, "ok": 248 }, { "date": "2026-10-14", "probes": 249, "ok": 249 }, { "date": "2026-10-15", "probes": 253, "ok": 253 }, { "date": "2026-10-16", "probes": 252, "ok": 252 }, { "date": "2026-10-17", "probes": 253, "ok": 253 }, { "date": "2026-10-18", "probes": 256, "ok": 256 }, { "date": "2026-10-19", "probes": 255, "ok": 255 }, { "date": "2026-10-20", "probes": 252, "ok": 252 }, { "date": "2026-10-21", "probes": 253, "ok": 253 }, { "date": "2026-10-22", "probes": 253, "ok": 253 }, { "date": "2026-10-23", "probes": 248, "ok": 248 }, { "date": "2026-10-24", "probes": 251, "ok": 251 }, { "date": "2026-10-25", "probes": 250, "ok": 250 }, { "date": "2026-10-26", "probes": 252, "ok": 252 }, { "date": "2026-10-27", "probes": 249, "ok": 249 }, { "date": "2026-10-28", "probes": 251, "ok": 251 }, { "date": "2026-10-29", "probes": 248, "ok": 248 }, { "date": "2026-10-30", "probes": 249, "ok": 249 }, { "date": "2026-10-31", "probes": 251, "ok": 251 }, { "date": "2026-11-01", "probes": 249, "ok": 249 }, { "date": "2026-11-02", "probes": 250, "ok": 250 }, { "date": "2026-11-03", "probes": 248, "ok": 248 }, { "date": "2026-11-04", "probes": 246, "ok": 246 }, { "date": "2026-11-05", "probes": 185, "ok": 185 }, { "date": "2026-11-06", "probes": 241, "ok": 241 }, { "date": "2026-11-07", "probes": 233, "ok": 233 } ] }, "vendorStatus": { "page": "https://status.mailchimp.com", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-11-03T02:16:31.252088609Z" }, "versions": [ { "registry": "npm", "name": "@mailchimp/mailchimp_transactional", "version": "1.4.1", "seenAt": "2026-11-06T23:42:24.513614416Z" }, { "registry": "pypi", "name": "mailchimp-transactional", "version": "1.4.1", "released": "2026-03-24", "seenAt": "2026-11-06T23:42:24.765704244Z" } ], "githubStars": 48, "npmWeekly": 267560, "pypiWeekly": 149515, "securityTxt": { "url": "https://mailchimp.com/.well-known/security.txt", "state": "valid", "checkedAt": "2026-11-07T15:59:41.954623744Z" }, "llmsTxt": { "url": "https://mailchimp.com/developer/transactional/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-11-07T15:32:58.112257648Z" }, "domain": { "domain": "mailchimp.com", "registered": "2001-06-29", "source": "https://rdap.verisign.com/com/v1/domain/mailchimp.com", "checkedAt": "2026-11-01T14:09:51.942989092Z" }, "pages": [ { "url": "https://mailchimp.com/pricing/transactional-email/", "kind": "pricing", "status": 200, "checkedAt": "2026-11-07T14:13:48.331406023Z", "changedAt": "2026-11-07T14:13:48.331406023Z", "fingerprint": "fe3263508aea" } ], "mcpTools": { "url": "https://mandrillapp.com/mcp", "checkedAt": "2026-11-07T01:46:08.092473858Z", "status": "error", "note": "initialize: Authorization: Bearer \u003capi_key\u003e required", "changedAt": "2026-11-07T01:46:08.092473858Z" }, "github": { "repo": "mailchimp/mailchimp-client-lib-codegen", "checkedAt": "2026-11-02T09:02:15.007153606Z", "stars": 48, "archived": false, "issuesEnabled": false, "pushedAt": "2026-07-16T14:41:25Z", "openIssues": 0, "openPRs": 13, "issuesOpened90d": 0, "issuesClosed90d": 0, "prsMerged90d": 0, "ci": { "branch": "main", "runs": 50, "success": 15, "failure": 15, "other": 20, "latest": "failure", "latestAt": "2026-07-16T14:43:21Z" } }, "updatedAt": "2026-11-07T22:56:07.717141563Z" } }, "answer": "Mailchimp Transactional (Mandrill) scores 61.5 (C) on agent readiness against SendLayer's 47.7 (D), and leads in 5 of 7 scored categories. SendLayer leads on maintenance \u0026 community.", "b": { "slug": "sendlayer", "name": "SendLayer", "vendor": "SendLayer, LLC", "vendorUrl": "https://sendlayer.com", "kind": "http-api", "category": "email", "summary": "SendLayer is a transactional email service from SendLayer, LLC, with an SMTP relay, a REST API for sending and email events, webhooks, SDKs in five languages and a hosted MCP server. It is aimed largely at WordPress and small-business sites.", "url": "https://www.anchorterminal.com/tools/sendlayer", "markdownUrl": "https://www.anchorterminal.com/tools/sendlayer.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/sendlayer.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/sendlayer.json", "dns": "sendlayer.grade.anchorterminal.com", "transports": [ "http", "streamable-http" ], "remoteUrl": "https://mcp.sendlayer.com", "packages": [ { "registry": "npm", "name": "sendlayer" }, { "registry": "pypi", "name": "sendlayer" } ], "auth": "api-key", "authNotes": "Bearer API key in the `Authorization` header, created per sending domain in the dashboard (one is made when a domain is authorised). Keys can be labelled and deleted; no scopes or read-only keys were found. The hosted MCP server takes the same key in an `x-sendlayer-api-key` or `Authorization` header.", "pricing": "paid", "pricingNotes": "Plans billed annually. Starter $5 a month for 1,000 emails, Business $15 for 5,000, Growth $25 for 10,000, Scale 20,000+ by quote. A free trial sends up to 200 emails. Accounts that reach their limit are upgraded automatically. 14-day money-back guarantee.", "priceSummary": "$5 / mo", "where": "hosted", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the developer docs, llms.txt, the OpenAPI file or the pricing page (checked 2026-11-06).", "endpoints": [] }, "toolCount": 5, "popularity": { "githubStars": null, "npmWeekly": 113, "pypiWeekly": 9, "asOf": "2026-11-06" }, "docsUrl": "https://developers.sendlayer.com/", "llmsTxt": "https://developers.sendlayer.com/llms.txt", "openapi": "https://developers.sendlayer.com/api-reference/sendlayer.json", "capabilities": [ "email.send", "email.analytics", "email.domains" ], "tags": [ "hosted", "closed-source", "smtp", "webhooks", "openapi", "llms-txt", "mcp", "remote-mcp", "status-page", "typescript", "python", "php", "ruby", "go" ], "lastRelease": "2026-08-21", "graded": true, "anchor": { "graded": true, "score": 47.7, "grade": "D", "agentReady": false, "rank": 1148, "ranked": true, "rankOf": 1510, "categoryRank": 19, "methodology": "0.7", "run": "2026-10-01", "scores": { "ergonomics": 62, "maintenance": 40, "payments": 20, "reliability": 48, "schema": 68, "security": 38, "transparency": 49 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-11-06" }, "negative": 0, "verdict": "A small API with an OpenAPI file, llms.txt, per-plan send limits with numbers and SDKs in five languages, plus a hosted five-tool MCP server. Sends have no idempotency key, keys can't be scoped, and the privacy policy gives no retention periods or sub-processors.", "bestFor": "Low-volume transactional mail for WordPress and small sites.", "strengths": [ "Send limits per minute, hour and day are published for each plan", "OpenAPI file, llms.txt and Markdown copies of every developer page", "Official SDKs for Node, Python, PHP, Ruby and Go", "Hosted MCP server at mcp.sendlayer.com with five tools for sending, events and webhooks", "Numbered error codes with messages for each missing or invalid field" ], "weaknesses": [ "No idempotency key on sends, so a retried request can send twice", "API keys can't be scoped or made read-only", "Status history shows 98 automated outage entries in 90 days with no durations or write-ups", "Privacy policy has no date, retention periods, DPA or sub-processor list", "No public changelog, SLA, security.txt or disclosure policy found" ], "agentNotes": [ "Check the email log with `GET /api/v1/events` before retrying a failed send, since sends have no idempotency key", "Keep To and CC at 10 addresses or fewer and BCC at 5, or the API returns error code 20 or 27", "Pace sends to the plan's per-minute limit, 50 on Starter and 120 on Business, and back off on 429", "Pass the API key in a header to mcp.sendlayer.com; the server answers 405 to anything but POST" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "D", "methodology": "0.7", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 47.7 } ], "editorialScores": { "ergonomics": 62, "maintenance": 40, "payments": 20, "reliability": 48, "schema": 68, "security": 38, "transparency": 23 }, "provenanceScore": 75, "checked": { "categories": { "ergonomics": "2026-11-06", "maintenance": "2026-11-06", "payments": "2026-11-06", "reliability": "2026-11-06", "schema": "2026-11-06", "security": "2026-11-06", "transparency": "2026-11-06" }, "last": "2026-11-06", "oldest": "2026-11-06", "stale": false, "staleAfterDays": 90 } }, "connect": { "install": "npm install sendlayer", "http": "curl https://console.sendlayer.com/api/v1/email -X POST -H \"Authorization: Bearer $SENDLAYER_API_KEY\" -H \"Content-Type: application/json\" -d '{\"From\":{\"name\":\"You\",\"email\":\"you@yourdomain.com\"},\"To\":[{\"name\":\"Person\",\"email\":\"person@example.com\"}],\"Subject\":\"Hello\",\"ContentType\":\"Text\",\"PlainContent\":\"Hello\"}'", "claudeCode": "claude mcp add --scope user --transport http sendlayer-mcp https://mcp.sendlayer.com --header \"Authorization: Bearer YOUR_SENDLAYER_API_KEY\"", "config": { "mcpServers": { "sendlayer": { "headers": { "x-sendlayer-api-key": "YOUR_SENDLAYER_API_KEY" }, "url": "https://mcp.sendlayer.com" } } } }, "letme": { "capability": "https://letme.dev/email.send", "tool": "https://letme.dev/sendlayer" }, "area": "communication", "unitPrices": [ { "item": "Starter", "unit": "month", "usd": 5, "note": "1,000 emails a month, billed annually" }, { "item": "Business", "unit": "month", "usd": 15, "note": "5,000 emails a month, billed annually" }, { "item": "Growth", "unit": "month", "usd": 25, "note": "10,000 emails a month, billed annually" } ], "provenance": { "legalEntity": "SendLayer, LLC", "domain": "sendlayer.com", "domainRegistered": "2015-07-22", "endpointOnVendorDomain": true, "terms": "https://sendlayer.com/terms-of-service/", "privacy": "https://sendlayer.com/privacy-policy/", "statusPage": "https://status.sendlayer.com", "changelog": "", "securityTxt": "none", "checked": "2026-11-06", "notes": [ "The terms name SendLayer, LLC under Florida law with courts in West Palm Beach. Neither the terms nor the privacy policy carries a date.", "The terms contain no clause on automated access to the website.", "sendlayer.com/robots.txt disallows only WordPress internals, cart and search paths. developers.sendlayer.com allows all but /_next/ and /cdn-cgi/.", "RDAP gives sendlayer.com a registration date of 22 July 2015; the about page says the team started SendLayer in 2022, and the footer copyright runs from 2021.", "/.well-known/security.txt returns 404." ], "score": 75 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/sendlayer.json", "live": { "slug": "sendlayer", "probe": { "target": "https://mcp.sendlayer.com", "method": "get", "lastAt": "2026-11-07T22:56:20.444245885Z", "lastOk": true, "lastStatus": 405, "lastMs": 460, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 334, "p95ms24h": 425, "samples24h": 244, "samples30d": 246, "days": [ { "date": "2026-11-06", "probes": 13, "ok": 13 }, { "date": "2026-11-07", "probes": 233, "ok": 233 } ] }, "vendorStatus": { "page": "https://status.sendlayer.com", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-11-07T04:48:44.410046578Z" }, "versions": [ { "registry": "npm", "name": "sendlayer", "version": "1.1.0", "seenAt": "2026-11-07T00:04:36.013206716Z" }, { "registry": "pypi", "name": "sendlayer", "version": "1.1.0", "released": "2026-08-21", "seenAt": "2026-11-07T00:04:36.403864413Z" } ], "npmWeekly": 113, "pypiWeekly": 9, "securityTxt": { "url": "https://sendlayer.com/.well-known/security.txt", "state": "none", "checkedAt": "2026-11-07T16:00:08.464258052Z" }, "llmsTxt": { "url": "https://developers.sendlayer.com/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-11-07T15:33:54.535300528Z" }, "pages": [ { "url": "https://sendlayer.com/privacy-policy/", "kind": "privacy", "status": 200, "checkedAt": "2026-11-07T14:19:27.507195007Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "1f5bea738989" }, { "url": "https://sendlayer.com/terms-of-service/", "kind": "terms", "status": 200, "checkedAt": "2026-11-07T14:19:31.497088663Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "1fbf9877b12a" } ], "mcpTools": { "url": "https://mcp.sendlayer.com", "checkedAt": "2026-11-07T01:47:41.040426143Z", "status": "auth", "note": "asks for credentials before listing its tools", "changedAt": "2026-11-07T01:47:41.040426143Z" }, "updatedAt": "2026-11-07T22:56:20.444245885Z" } }, "edges": [ { "by": 30, "category": "security", "leads": "mandrill", "name": "Security \u0026 auth", "reasons": { "a": "API keys are created and revoked in the web app, several to an account, and each can be limited to chosen endpoints and to IP addresses. Keys do not expire and no rotation tooling was found. A new key has full account access by default. The key travels in the JSON body or a Bearer header, not the URL (26). Per-endpoint key permissions, IP limits, test keys that send nothing and subaccounts that can be paused. No approval step for sends or deletes (15). The API and the MCP server return inbound mail and stored message content, which is untrusted text. No guidance on prompt injection was found in the MCP guide or the docs (3). The Account Security page lists the IP addresses that used the account and whether each came by API, SMTP or web, and searches can filter by API key (10). A responsible disclosure programme with no rewards, a security.txt with a contact and no Expires field, SOC 2 reports and ISO 27001 per the security page, and regular penetration tests. No public advisory feed found (14).", "b": "Plain revocable API keys per domain, several allowed, sent in a header; no scopes, expiry or rotation feature beyond creating and deleting keys (20 of 30). No read-only key or approval step (0 of 20). The API returns event data, not received mail (10 of 15). Email logs kept 3, 15 or 30 days by plan, and no log of API calls was found (8 of 15). No security.txt (404), disclosure policy, bug bounty or certification found (0 of 20). Total 38." }, "scores": { "a": 68, "b": 38 } }, { "by": 22, "category": "reliability", "leads": "mandrill", "name": "Reliability", "reasons": { "a": "Graded on the hosted Transactional API with the hosted lines. status.mailchimp.com lists Mailchimp Transactional as its own component and keeps event history by month (20). In the 90 days from 6 August 2026 it shows three Transactional incidents, all sending delays, on 1 September (16:19 to 20:27 UTC, \"select\" accounts), 15 September (13:36 to 18:02 UTC, \"a subset of customers\") and 17 September (23:31 to 00:09 UTC, \"a subset of customers\"). Each hit part of the accounts and none is described as the API being down, so minor only (20). Published numbers cover `/messages/search` at 20 calls a minute, test mode at 10,000 messages a day and the demo at 25 emails an hour. The hourly sending quota is set from reputation with no figure, and no general request limit was found (10). The search endpoint returns 429 and the release notes say to retry 60 seconds after the first of the 20 calls. Mail over the hourly quota is queued in a backlog and not refused. No idempotency key for sends was found, so this is retry-wait guidance alone (10). No SLA found, and the additional terms supply the service as-is (0). Generally available (10). 20+20+10+10+0+10 = 70.", "b": "Graded with the hosted lines. A Cronitor status page at status.sendlayer.com with components for the app, SMTP, tracking links, the website and each plan's sending IPs, and a history (15 of 20, see below). The 90 days from 8 August hold 98 automated outage entries, 13 of them on SendLayer Services Health, most on per-plan IP monitors, all marked resolved but with no durations or write-ups, so their size can't be judged (5 of 30). Send limits per minute, hour and day are published per plan, plus recipient and size caps (15). 429 appears in the error code list, with no Retry-After, backoff guidance or idempotency for sends (3 of 15). No SLA found (0). The API is at v1 with no beta label (10). The status page's uptime columns showed no data on 6 November, so the component line takes 15 of 20 rather than 20. Total 48." }, "scores": { "a": 70, "b": 48 } }, { "by": 22, "category": "transparency", "leads": "mandrill", "name": "Transparency \u0026 trust", "reasons": { "a": "Closed service with published terms and a named contracting entity. The client libraries are source-available under Mailchimp's own licence agreement, which is not an OSI licence (15). The additional terms and the docs agree that sent message content is kept 30 days, the docs add 90 days for bounce details and 48 hours for the backlog, and a data processing addendum dated 26 September 2024 covers deletion. The terms add that retention is not guaranteed (24). No deprecation policy was found, and the API Use Policy says the APIs can change by a posting or an email. Past notices carried dates, such as the TLS 1.0 and 1.1 retirement announced on 5 June 2023 for 18 July 2023 (10). A sub-processor list with locations is public but was last updated on 29 February 2024, and the security page places Mailchimp's own servers in United States data centres (15).", "b": "Closed service with terms naming SendLayer, LLC under Florida law (15 of 30). The privacy policy is undated, says data is kept as long as the account is active or as needed, and names no retention periods, DPA or processors; only the pricing page gives log retention per plan (8 of 30). No deprecation policy or dated notices (0). No sub-processors or data locations disclosed (0). Total 23." }, "scores": { "a": 71, "b": 49 } }, { "by": 15, "category": "payments", "leads": "mandrill", "name": "Payments \u0026 pricing", "reasons": { "a": "No x402, MPP or L402 (0). Block prices are public without a login, $20 per 25,000 emails falling to $10, and $29.95 a month for a dedicated IP. Full use also needs a Standard or Premium marketing plan, whose price is on a separate page (20). The demo gives 500 emails once on any Mailchimp account, free plan included. We take 5 off because it sends only to the account's own verified domain and we could not confirm that signup asks for no card (15). A person signs up in a browser, enables the add-on, creates a key and sets DNS records, so there is no autonomous route (0).", "b": "No x402, MPP or L402 (0). Plan prices are public but only as annual plans, with no per-email overage price; accounts are upgraded automatically at the limit (10 of 20). A free trial of 200 emails is offered through checkout; whether it needs a card couldn't be read, since robots.txt disallows the add-to-cart URLs (10 of 20). A person signs up and authorises a domain in a browser (0). Total 20." }, "scores": { "a": 35, "b": 20 } }, { "by": 12, "category": "maintenance", "leads": "sendlayer", "name": "Maintenance \u0026 community", "reasons": { "a": "The newest dated Transactional release is specification 1.4.1 on 24 March 2026 (commit a996b63 in the generator repository), with the Node and Python libraries at 1.4.1, 225 days before this check (0). No dated Transactional release or changelog entry in the 90 days from 6 August. The newest Transactional release-notes entry is 19 August 2025 (0). A public changelog, a support contact and an API help address in the specification. We saw no public issue replies (6). The Node and Python libraries are both at 1.4.1 and match the current API version (15). The generator repository has workflows that validate the specification and build and test each library, and the Node library was updated in February 2024 for an Axios advisory. The test workflow needs a secret key, so we could not see results (7). 0+0+6+15+7 = 28.", "b": "The Node and Python SDKs were last released as 1.1.0 on 21 August 2026, 77 days before this check (20). One SDK release in the 90 days and no dated changelog (0 of 20). A closed service with a support form and docs updated through 2026, but no public changelog (5 of 15). Not in the official MCP registry (search for sendlayer returned nothing on 6 November). Official SDKs in five languages (10 of 15). The SDK repositories exist on GitHub under sendlayer; their CI wasn't read (5 of 10). Total 40." }, "scores": { "a": 28, "b": 40 } }, { "by": 11, "category": "schema", "leads": "mandrill", "name": "Schema \u0026 documentation", "reasons": { "a": "An OpenAPI 3.1 file with all 99 operations is public at mailchimp.com/developer/openapi/api-reference-2.json, and a Swagger 2.0 copy sits in the client library repository. The link to it in the Transactional llms.txt returns 404 (25). llms.txt for the developer site and for Transactional, and a Markdown copy of every page at the URL plus `.md` (10). Each operation has a summary and a description averaging about 120 characters. They say what a call does and seldom when not to use it (11). Request bodies carry 36 enums, required fields, date patterns and minimum and maximum values. Headers, metadata and merge variables are free-form objects (11). Reference pages show request and response samples with code in eight languages, and each operation lists typed error bodies. The OpenAPI file itself has no examples (13). The version is in the path, but the docs use 1.0, 1.3 and 1.4 in different places, and the public changelog has nothing newer than 19 August 2025, so the move to 1.4 in March 2026 is not in it (9).", "b": "OpenAPI file at developers.sendlayer.com/api-reference/sendlayer.json (version 1.0.1) covering four paths, send, events and webhooks (25). llms.txt and Markdown copies of every developer page (10). Operation summaries say what each call does; nothing says when not to use one, and the hosted MCP server's tool definitions aren't public (10 of 20). Parameters are typed but without enums or limits, and the event filter is a free string (7 of 15). Code samples in five languages and a table of 35 error codes, but the spec documents only 200 responses (11 of 15). Version in the path and in the spec, with no public changelog (5 of 15). Total 68." }, "scores": { "a": 79, "b": 68 } } ], "facts": [ { "a": "HTTP API", "b": "HTTP API", "name": "Kind" }, { "a": "Intuit Mailchimp", "b": "SendLayer, LLC", "name": "Vendor" }, { "a": "https://mandrillapp.com/api/1.4", "b": "https://mcp.sendlayer.com", "name": "Hosted endpoint" }, { "a": "HTTP", "b": "HTTP, Streamable HTTP", "name": "Transports" }, { "a": "API key", "b": "API key", "name": "Auth" }, { "a": "Paid", "b": "Paid", "name": "Pricing" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "Proprietary service under Mailchimp's Standard Terms of Use and Additional Terms. The client libraries are under Mailchimp's own client library licence agreement", "b": "none", "name": "Licence" }, { "a": "9", "b": "5", "name": "Tools exposed" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "yes", "name": "llms.txt" }, { "a": "2026-03-24", "b": "2026-08-21", "name": "Last release" }, { "a": "no date given", "b": "no date given", "name": "Terms last updated" }, { "a": "2026-03-09", "b": "no date given", "name": "Privacy policy last updated" }, { "a": "yes", "b": "not found in the text", "name": "Customer content may train models" }, { "a": "not found in the text", "b": "not found in the text", "name": "Terms restrict automated access" }, { "a": "not found in the text", "b": "not found in the text", "name": "Terms restrict benchmarking" }, { "a": "yes", "b": "yes", "name": "Terms or service can change without notice" }, { "a": "yes", "b": "not found in the text", "name": "Arbitration or class-action waiver" }, { "a": "226k npm/wk, 132k PyPI/wk", "b": "113 npm/wk, 9 PyPI/wk", "name": "Popularity" } ], "faq": [ { "answer": "Mailchimp Transactional (Mandrill) scores 61.5 (C) on agent readiness against SendLayer's 47.7 (D), and leads in 5 of 7 scored categories. SendLayer leads on maintenance \u0026 community.", "question": "Which is better for AI agents, Mailchimp Transactional (Mandrill) or SendLayer?" }, { "answer": "Both need an API key.", "question": "Do Mailchimp Transactional (Mandrill) and SendLayer need an API key?" }, { "answer": "Yes. Mailchimp Transactional (Mandrill) has a hosted endpoint at https://mandrillapp.com/api/1.4 and SendLayer at https://mcp.sendlayer.com.", "question": "Can an agent call Mailchimp Transactional (Mandrill) and SendLayer without installing anything?" } ], "goodFor": [ { "aheadOn": [ "Reliability, 70 against 48", "Schema \u0026 documentation, 79 against 68", "Security \u0026 auth, 68 against 38", "Payments \u0026 pricing, 35 against 20", "Transparency \u0026 trust, 71 against 49" ], "also": null, "goodFor": "Teams already paying for Mailchimp Standard or Premium that want transactional mail, inbound parsing and an MCP server on the same account.", "slug": "mandrill", "watchFor": "Full use needs a Standard or Premium Mailchimp marketing plan in addition to the email blocks" }, { "aheadOn": [ "Maintenance \u0026 community, 40 against 28" ], "also": null, "goodFor": "Low-volume transactional mail for WordPress and small sites.", "slug": "sendlayer", "watchFor": "No idempotency key on sends, so a retried request can send twice" } ], "history": { "mandrill": [ { "causes": [ "correction" ], "date": "2026-11-04", "delta": 3.4, "from": 58.1, "fromGrade": "C", "to": 61.5, "toGrade": "C" } ], "sendlayer": null }, "job": { "capability": "email.send", "name": "Sending email" }, "others": [ { "json": "https://www.anchorterminal.com/compare/ahasend-vs-mandrill.json", "title": "AhaSend API + MCP vs Mailchimp Transactional (Mandrill)", "url": "https://www.anchorterminal.com/compare/ahasend-vs-mandrill" }, { "json": "https://www.anchorterminal.com/compare/ahasend-vs-sendlayer.json", "title": "AhaSend API + MCP vs SendLayer", "url": "https://www.anchorterminal.com/compare/ahasend-vs-sendlayer" }, { "json": "https://www.anchorterminal.com/compare/amazon-ses-vs-mandrill.json", "title": "Amazon SES vs Mailchimp Transactional (Mandrill)", "url": "https://www.anchorterminal.com/compare/amazon-ses-vs-mandrill" }, { "json": "https://www.anchorterminal.com/compare/amazon-ses-vs-sendlayer.json", "title": "Amazon SES vs SendLayer", "url": "https://www.anchorterminal.com/compare/amazon-ses-vs-sendlayer" }, { "json": "https://www.anchorterminal.com/compare/brevo-vs-mandrill.json", "title": "Brevo API + MCP vs Mailchimp Transactional (Mandrill)", "url": "https://www.anchorterminal.com/compare/brevo-vs-mandrill" }, { "json": "https://www.anchorterminal.com/compare/brevo-vs-sendlayer.json", "title": "Brevo API + MCP vs SendLayer", "url": "https://www.anchorterminal.com/compare/brevo-vs-sendlayer" }, { "json": "https://www.anchorterminal.com/compare/cloudflare-email-service-vs-mandrill.json", "title": "Cloudflare Email Service vs Mailchimp Transactional (Mandrill)", "url": "https://www.anchorterminal.com/compare/cloudflare-email-service-vs-mandrill" }, { "json": "https://www.anchorterminal.com/compare/cloudflare-email-service-vs-sendlayer.json", "title": "Cloudflare Email Service vs SendLayer", "url": "https://www.anchorterminal.com/compare/cloudflare-email-service-vs-sendlayer" }, { "json": "https://www.anchorterminal.com/compare/groundmail-vs-mandrill.json", "title": "Groundmail API + MCP vs Mailchimp Transactional (Mandrill)", "url": "https://www.anchorterminal.com/compare/groundmail-vs-mandrill" }, { "json": "https://www.anchorterminal.com/compare/groundmail-vs-sendlayer.json", "title": "Groundmail API + MCP vs SendLayer", "url": "https://www.anchorterminal.com/compare/groundmail-vs-sendlayer" }, { "json": "https://www.anchorterminal.com/compare/loops-vs-mandrill.json", "title": "Loops API + MCP vs Mailchimp Transactional (Mandrill)", "url": "https://www.anchorterminal.com/compare/loops-vs-mandrill" }, { "json": "https://www.anchorterminal.com/compare/loops-vs-sendlayer.json", "title": "Loops API + MCP vs SendLayer", "url": "https://www.anchorterminal.com/compare/loops-vs-sendlayer" }, { "json": "https://www.anchorterminal.com/compare/mailersend-vs-mandrill.json", "title": "MailerSend vs Mailchimp Transactional (Mandrill)", "url": "https://www.anchorterminal.com/compare/mailersend-vs-mandrill" }, { "json": "https://www.anchorterminal.com/compare/mailersend-vs-sendlayer.json", "title": "MailerSend vs SendLayer", "url": "https://www.anchorterminal.com/compare/mailersend-vs-sendlayer" }, { "json": "https://www.anchorterminal.com/compare/mailgun-vs-mandrill.json", "title": "Mailgun API + MCP vs Mailchimp Transactional (Mandrill)", "url": "https://www.anchorterminal.com/compare/mailgun-vs-mandrill" }, { "json": "https://www.anchorterminal.com/compare/mailgun-vs-sendlayer.json", "title": "Mailgun API + MCP vs SendLayer", "url": "https://www.anchorterminal.com/compare/mailgun-vs-sendlayer" }, { "json": "https://www.anchorterminal.com/compare/mailjet-vs-mandrill.json", "title": "Mailjet API + MCP vs Mailchimp Transactional (Mandrill)", "url": "https://www.anchorterminal.com/compare/mailjet-vs-mandrill" }, { "json": "https://www.anchorterminal.com/compare/mailjet-vs-sendlayer.json", "title": "Mailjet API + MCP vs SendLayer", "url": "https://www.anchorterminal.com/compare/mailjet-vs-sendlayer" }, { "json": "https://www.anchorterminal.com/compare/mailpace-vs-mandrill.json", "title": "MailPace vs Mailchimp Transactional (Mandrill)", "url": "https://www.anchorterminal.com/compare/mailpace-vs-mandrill" }, { "json": "https://www.anchorterminal.com/compare/mailpace-vs-sendlayer.json", "title": "MailPace vs SendLayer", "url": "https://www.anchorterminal.com/compare/mailpace-vs-sendlayer" }, { "json": "https://www.anchorterminal.com/compare/mailtrap-vs-mandrill.json", "title": "Mailtrap Email API + MCP vs Mailchimp Transactional (Mandrill)", "url": "https://www.anchorterminal.com/compare/mailtrap-vs-mandrill" }, { "json": "https://www.anchorterminal.com/compare/mailtrap-vs-sendlayer.json", "title": "Mailtrap Email API + MCP vs SendLayer", "url": "https://www.anchorterminal.com/compare/mailtrap-vs-sendlayer" }, { "json": "https://www.anchorterminal.com/compare/mandrill-vs-postmark.json", "title": "Mailchimp Transactional (Mandrill) vs Postmark API + MCP", "url": "https://www.anchorterminal.com/compare/mandrill-vs-postmark" }, { "json": "https://www.anchorterminal.com/compare/mandrill-vs-resend.json", "title": "Mailchimp Transactional (Mandrill) vs Resend API + MCP", "url": "https://www.anchorterminal.com/compare/mandrill-vs-resend" }, { "json": "https://www.anchorterminal.com/compare/mandrill-vs-sendgrid.json", "title": "Mailchimp Transactional (Mandrill) vs Twilio SendGrid", "url": "https://www.anchorterminal.com/compare/mandrill-vs-sendgrid" }, { "json": "https://www.anchorterminal.com/compare/mandrill-vs-smtp2go.json", "title": "Mailchimp Transactional (Mandrill) vs SMTP2GO API + MCP", "url": "https://www.anchorterminal.com/compare/mandrill-vs-smtp2go" }, { "json": "https://www.anchorterminal.com/compare/mandrill-vs-zoho-zeptomail.json", "title": "Mailchimp Transactional (Mandrill) vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/mandrill-vs-zoho-zeptomail" }, { "json": "https://www.anchorterminal.com/compare/postmark-vs-sendlayer.json", "title": "Postmark API + MCP vs SendLayer", "url": "https://www.anchorterminal.com/compare/postmark-vs-sendlayer" }, { "json": "https://www.anchorterminal.com/compare/resend-vs-sendlayer.json", "title": "Resend API + MCP vs SendLayer", "url": "https://www.anchorterminal.com/compare/resend-vs-sendlayer" }, { "json": "https://www.anchorterminal.com/compare/sendgrid-vs-sendlayer.json", "title": "Twilio SendGrid vs SendLayer", "url": "https://www.anchorterminal.com/compare/sendgrid-vs-sendlayer" }, { "json": "https://www.anchorterminal.com/compare/sendlayer-vs-smtp2go.json", "title": "SendLayer vs SMTP2GO API + MCP", "url": "https://www.anchorterminal.com/compare/sendlayer-vs-smtp2go" }, { "json": "https://www.anchorterminal.com/compare/sendlayer-vs-zoho-zeptomail.json", "title": "SendLayer vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/sendlayer-vs-zoho-zeptomail" } ], "panel": null, "scores": [ { "by": 22, "edge": "mandrill", "key": "reliability", "mandrill": 70, "name": "Reliability", "sendlayer": 48, "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "by": 11, "edge": "mandrill", "key": "schema", "mandrill": 79, "name": "Schema \u0026 documentation", "sendlayer": 68, "weight": 13 }, { "by": 2, "edge": "sendlayer", "key": "ergonomics", "mandrill": 60, "name": "Agent ergonomics", "sendlayer": 62, "weight": 13 }, { "by": 30, "edge": "mandrill", "key": "security", "mandrill": 68, "name": "Security \u0026 auth", "sendlayer": 38, "weight": 14 }, { "by": 15, "edge": "mandrill", "key": "payments", "mandrill": 35, "name": "Payments \u0026 pricing", "sendlayer": 20, "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "by": 12, "edge": "sendlayer", "key": "maintenance", "mandrill": 28, "name": "Maintenance \u0026 community", "sendlayer": 40, "weight": 7 }, { "by": 22, "edge": "mandrill", "key": "transparency", "mandrill": 71, "name": "Transparency \u0026 trust", "sendlayer": 49, "weight": 7 } ], "summary": "Mailchimp Transactional (Mandrill) scores 61.5 (C) on agent readiness against SendLayer's 47.7 (D), and leads in 5 of 7 scored categories. SendLayer leads on maintenance \u0026 community. Both do sending email.", "tasks": null, "tutorials": [], "verdicts": { "mandrill": "A public OpenAPI 3.1 file covers all 99 operations, the docs serve Markdown and llms.txt, and keys can be limited by endpoint and IP address. Sending needs a Standard or Premium Mailchimp plan plus $20 blocks of 25,000 emails. No send idempotency key or SLA was found, and the newest dated release is from 24 March 2026.", "sendlayer": "A small API with an OpenAPI file, llms.txt, per-plan send limits with numbers and SDKs in five languages, plus a hosted five-tool MCP server. Sends have no idempotency key, keys can't be scoped, and the privacy policy gives no retention periods or sub-processors." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/mandrill-vs-sendlayer", "json": "https://www.anchorterminal.com/compare/mandrill-vs-sendlayer.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/mandrill-vs-sendlayer.md", "mcp": "https://www.anchorterminal.com/mcp", "slim": "https://www.anchorterminal.com/compare/mandrill-vs-sendlayer.min.md" }, "markdown": "Mailchimp Transactional (Mandrill) scores 61.5 (C) on agent readiness against SendLayer's 47.7 (D), and leads in 5 of 7 scored categories. SendLayer leads on maintenance \u0026 community. Both do sending email.\n\n- Mailchimp Transactional (Mandrill): grade C, 61.5/100, rank #610 of 1510. Markdown https://www.anchorterminal.com/tools/mandrill.md · JSON https://www.anchorterminal.com/api/v1/tools/mandrill.json\n- SendLayer: grade D, 47.7/100, rank #1148 of 1510. Markdown https://www.anchorterminal.com/tools/sendlayer.md · JSON https://www.anchorterminal.com/api/v1/tools/sendlayer.json\n- Best email delivery APIs for AI agents: https://www.anchorterminal.com/best/email/index.md\n- All 174 email comparisons: https://www.anchorterminal.com/compare/email/index.md\n\n## Which one, for what\n\n### Mailchimp Transactional (Mandrill) (C)\n\nGood for: Teams already paying for Mailchimp Standard or Premium that want transactional mail, inbound parsing and an MCP server on the same account.\n\nAhead on:\n- Reliability, 70 against 48\n- Schema \u0026 documentation, 79 against 68\n- Security \u0026 auth, 68 against 38\n- Payments \u0026 pricing, 35 against 20\n- Transparency \u0026 trust, 71 against 49\n\nWatch for: Full use needs a Standard or Premium Mailchimp marketing plan in addition to the email blocks\n\n### SendLayer (D)\n\nGood for: Low-volume transactional mail for WordPress and small sites.\n\nAhead on:\n- Maintenance \u0026 community, 40 against 28\n\nWatch for: No idempotency key on sends, so a retried request can send twice\n\n\n## Why the edge\n\n### Security \u0026 auth: Mailchimp Transactional (Mandrill) +30\n\n- Mailchimp Transactional (Mandrill) (68): API keys are created and revoked in the web app, several to an account, and each can be limited to chosen endpoints and to IP addresses. Keys do not expire and no rotation tooling was found. A new key has full account access by default. The key travels in the JSON body or a Bearer header, not the URL (26). Per-endpoint key permissions, IP limits, test keys that send nothing and subaccounts that can be paused. No approval step for sends or deletes (15). The API and the MCP server return inbound mail and stored message content, which is untrusted text. No guidance on prompt injection was found in the MCP guide or the docs (3). The Account Security page lists the IP addresses that used the account and whether each came by API, SMTP or web, and searches can filter by API key (10). A responsible disclosure programme with no rewards, a security.txt with a contact and no Expires field, SOC 2 reports and ISO 27001 per the security page, and regular penetration tests. No public advisory feed found (14).\n- SendLayer (38): Plain revocable API keys per domain, several allowed, sent in a header; no scopes, expiry or rotation feature beyond creating and deleting keys (20 of 30). No read-only key or approval step (0 of 20). The API returns event data, not received mail (10 of 15). Email logs kept 3, 15 or 30 days by plan, and no log of API calls was found (8 of 15). No security.txt (404), disclosure policy, bug bounty or certification found (0 of 20). Total 38.\n\n### Reliability: Mailchimp Transactional (Mandrill) +22\n\n- Mailchimp Transactional (Mandrill) (70): Graded on the hosted Transactional API with the hosted lines. status.mailchimp.com lists Mailchimp Transactional as its own component and keeps event history by month (20). In the 90 days from 6 August 2026 it shows three Transactional incidents, all sending delays, on 1 September (16:19 to 20:27 UTC, \"select\" accounts), 15 September (13:36 to 18:02 UTC, \"a subset of customers\") and 17 September (23:31 to 00:09 UTC, \"a subset of customers\"). Each hit part of the accounts and none is described as the API being down, so minor only (20). Published numbers cover `/messages/search` at 20 calls a minute, test mode at 10,000 messages a day and the demo at 25 emails an hour. The hourly sending quota is set from reputation with no figure, and no general request limit was found (10). The search endpoint returns 429 and the release notes say to retry 60 seconds after the first of the 20 calls. Mail over the hourly quota is queued in a backlog and not refused. No idempotency key for sends was found, so this is retry-wait guidance alone (10). No SLA found, and the additional terms supply the service as-is (0). Generally available (10). 20+20+10+10+0+10 = 70.\n- SendLayer (48): Graded with the hosted lines. A Cronitor status page at status.sendlayer.com with components for the app, SMTP, tracking links, the website and each plan's sending IPs, and a history (15 of 20, see below). The 90 days from 8 August hold 98 automated outage entries, 13 of them on SendLayer Services Health, most on per-plan IP monitors, all marked resolved but with no durations or write-ups, so their size can't be judged (5 of 30). Send limits per minute, hour and day are published per plan, plus recipient and size caps (15). 429 appears in the error code list, with no Retry-After, backoff guidance or idempotency for sends (3 of 15). No SLA found (0). The API is at v1 with no beta label (10). The status page's uptime columns showed no data on 6 November, so the component line takes 15 of 20 rather than 20. Total 48.\n\n### Transparency \u0026 trust: Mailchimp Transactional (Mandrill) +22\n\n- Mailchimp Transactional (Mandrill) (71): Closed service with published terms and a named contracting entity. The client libraries are source-available under Mailchimp's own licence agreement, which is not an OSI licence (15). The additional terms and the docs agree that sent message content is kept 30 days, the docs add 90 days for bounce details and 48 hours for the backlog, and a data processing addendum dated 26 September 2024 covers deletion. The terms add that retention is not guaranteed (24). No deprecation policy was found, and the API Use Policy says the APIs can change by a posting or an email. Past notices carried dates, such as the TLS 1.0 and 1.1 retirement announced on 5 June 2023 for 18 July 2023 (10). A sub-processor list with locations is public but was last updated on 29 February 2024, and the security page places Mailchimp's own servers in United States data centres (15).\n- SendLayer (49): Closed service with terms naming SendLayer, LLC under Florida law (15 of 30). The privacy policy is undated, says data is kept as long as the account is active or as needed, and names no retention periods, DPA or processors; only the pricing page gives log retention per plan (8 of 30). No deprecation policy or dated notices (0). No sub-processors or data locations disclosed (0). Total 23.\n\n### Payments \u0026 pricing: Mailchimp Transactional (Mandrill) +15\n\n- Mailchimp Transactional (Mandrill) (35): No x402, MPP or L402 (0). Block prices are public without a login, $20 per 25,000 emails falling to $10, and $29.95 a month for a dedicated IP. Full use also needs a Standard or Premium marketing plan, whose price is on a separate page (20). The demo gives 500 emails once on any Mailchimp account, free plan included. We take 5 off because it sends only to the account's own verified domain and we could not confirm that signup asks for no card (15). A person signs up in a browser, enables the add-on, creates a key and sets DNS records, so there is no autonomous route (0).\n- SendLayer (20): No x402, MPP or L402 (0). Plan prices are public but only as annual plans, with no per-email overage price; accounts are upgraded automatically at the limit (10 of 20). A free trial of 200 emails is offered through checkout; whether it needs a card couldn't be read, since robots.txt disallows the add-to-cart URLs (10 of 20). A person signs up and authorises a domain in a browser (0). Total 20.\n\n### Maintenance \u0026 community: SendLayer +12\n\n- Mailchimp Transactional (Mandrill) (28): The newest dated Transactional release is specification 1.4.1 on 24 March 2026 (commit a996b63 in the generator repository), with the Node and Python libraries at 1.4.1, 225 days before this check (0). No dated Transactional release or changelog entry in the 90 days from 6 August. The newest Transactional release-notes entry is 19 August 2025 (0). A public changelog, a support contact and an API help address in the specification. We saw no public issue replies (6). The Node and Python libraries are both at 1.4.1 and match the current API version (15). The generator repository has workflows that validate the specification and build and test each library, and the Node library was updated in February 2024 for an Axios advisory. The test workflow needs a secret key, so we could not see results (7). 0+0+6+15+7 = 28.\n- SendLayer (40): The Node and Python SDKs were last released as 1.1.0 on 21 August 2026, 77 days before this check (20). One SDK release in the 90 days and no dated changelog (0 of 20). A closed service with a support form and docs updated through 2026, but no public changelog (5 of 15). Not in the official MCP registry (search for sendlayer returned nothing on 6 November). Official SDKs in five languages (10 of 15). The SDK repositories exist on GitHub under sendlayer; their CI wasn't read (5 of 10). Total 40.\n\n### Schema \u0026 documentation: Mailchimp Transactional (Mandrill) +11\n\n- Mailchimp Transactional (Mandrill) (79): An OpenAPI 3.1 file with all 99 operations is public at mailchimp.com/developer/openapi/api-reference-2.json, and a Swagger 2.0 copy sits in the client library repository. The link to it in the Transactional llms.txt returns 404 (25). llms.txt for the developer site and for Transactional, and a Markdown copy of every page at the URL plus `.md` (10). Each operation has a summary and a description averaging about 120 characters. They say what a call does and seldom when not to use it (11). Request bodies carry 36 enums, required fields, date patterns and minimum and maximum values. Headers, metadata and merge variables are free-form objects (11). Reference pages show request and response samples with code in eight languages, and each operation lists typed error bodies. The OpenAPI file itself has no examples (13). The version is in the path, but the docs use 1.0, 1.3 and 1.4 in different places, and the public changelog has nothing newer than 19 August 2025, so the move to 1.4 in March 2026 is not in it (9).\n- SendLayer (68): OpenAPI file at developers.sendlayer.com/api-reference/sendlayer.json (version 1.0.1) covering four paths, send, events and webhooks (25). llms.txt and Markdown copies of every developer page (10). Operation summaries say what each call does; nothing says when not to use one, and the hosted MCP server's tool definitions aren't public (10 of 20). Parameters are typed but without enums or limits, and the event filter is a free string (7 of 15). Code samples in five languages and a table of 35 error codes, but the spec documents only 200 responses (11 of 15). Version in the path and in the spec, with no public changelog (5 of 15). Total 68.\n\n## Score by category\n\n| Category | Weight | Mailchimp Transactional (Mandrill) | SendLayer | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 70 | 48 | Mailchimp Transactional (Mandrill) +22 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 79 | 68 | Mailchimp Transactional (Mandrill) +11 |\n| Agent ergonomics | 13% (16.2 this run) | 60 | 62 | SendLayer +2 |\n| Security \u0026 auth | 14% (17.5 this run) | 68 | 38 | Mailchimp Transactional (Mandrill) +30 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 35 | 20 | Mailchimp Transactional (Mandrill) +15 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 28 | 40 | SendLayer +12 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 71 | 49 | Mailchimp Transactional (Mandrill) +22 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **61.5 · C** | **47.7 · D** | |\n\n## Facts side by side\n\n| Fact | Mailchimp Transactional (Mandrill) | SendLayer |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Intuit Mailchimp | SendLayer, LLC |\n| Hosted endpoint | `https://mandrillapp.com/api/1.4` | `https://mcp.sendlayer.com` |\n| Transports | HTTP | HTTP, Streamable HTTP |\n| Auth | API key | API key |\n| Pricing | Paid | Paid |\n| x402 | no | no |\n| Licence | Proprietary service under Mailchimp's Standard Terms of Use and Additional Terms. The client libraries are under Mailchimp's own client library licence agreement | none |\n| Tools exposed | 9 | 5 |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| Last release | 2026-03-24 | 2026-08-21 |\n| Terms last updated | no date given | no date given |\n| Privacy policy last updated | 2026-03-09 | no date given |\n| Customer content may train models | yes | not found in the text |\n| Terms restrict automated access | not found in the text | not found in the text |\n| Terms restrict benchmarking | not found in the text | not found in the text |\n| Terms or service can change without notice | yes | yes |\n| Arbitration or class-action waiver | yes | not found in the text |\n| Popularity | 226k npm/wk, 132k PyPI/wk | 113 npm/wk, 9 PyPI/wk |\n\n## How the scores have moved\n\n### Mailchimp Transactional (Mandrill)\n\n- +3.4 on 4 November 2026: correction\n\n### SendLayer\n\nNo score change since it was listed.\n\n## Verdicts\n\n**Mailchimp Transactional (Mandrill).** A public OpenAPI 3.1 file covers all 99 operations, the docs serve Markdown and llms.txt, and keys can be limited by endpoint and IP address. Sending needs a Standard or Premium Mailchimp plan plus $20 blocks of 25,000 emails. No send idempotency key or SLA was found, and the newest dated release is from 24 March 2026.\n\n**SendLayer.** A small API with an OpenAPI file, llms.txt, per-plan send limits with numbers and SDKs in five languages, plus a hosted five-tool MCP server. Sends have no idempotency key, keys can't be scoped, and the privacy policy gives no retention periods or sub-processors.\n\n## Before you call either\n\n### Mailchimp Transactional (Mandrill)\n\n1. Send every call as POST with the key in the JSON body as `key`. The MCP server takes the same key as `Authorization: Bearer`\n2. Use a test API key while building. Test sends are free, capped at 10,000 a day, and deliver nothing\n3. Verify the sending domain with DKIM and DMARC first. Mail from an unverified domain is rejected with the reason `unsigned`\n4. Keep `/messages/search` under 20 calls a minute and set `limit` (default 100, maximum 1,000). There is no offset, so use an activity export for more\n5. For a restricted key that must also use the MCP server, enable the AI Agents permission group on the key\n\n### SendLayer\n\n1. Check the email log with `GET /api/v1/events` before retrying a failed send, since sends have no idempotency key\n2. Keep To and CC at 10 addresses or fewer and BCC at 5, or the API returns error code 20 or 27\n3. Pace sends to the plan's per-minute limit, 50 on Starter and 120 on Business, and back off on 429\n4. Pass the API key in a header to mcp.sendlayer.com; the server answers 405 to anything but POST\n\n## Questions\n\n### Which is better for AI agents, Mailchimp Transactional (Mandrill) or SendLayer?\n\nMailchimp Transactional (Mandrill) scores 61.5 (C) on agent readiness against SendLayer's 47.7 (D), and leads in 5 of 7 scored categories. SendLayer leads on maintenance \u0026 community.\n\n### Do Mailchimp Transactional (Mandrill) and SendLayer need an API key?\n\nBoth need an API key.\n\n### Can an agent call Mailchimp Transactional (Mandrill) and SendLayer without installing anything?\n\nYes. Mailchimp Transactional (Mandrill) has a hosted endpoint at https://mandrillapp.com/api/1.4 and SendLayer at https://mcp.sendlayer.com.\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/mandrill-vs-sendlayer.json, and with the fewest tokens: https://www.anchorterminal.com/compare/mandrill-vs-sendlayer.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"mandrill\", \"b\": \"sendlayer\"}`. From a terminal: `anchor compare mandrill sendlayer`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/mandrill.json and https://www.anchorterminal.com/api/v1/tools/sendlayer.json\n\n## Other comparisons with Mailchimp Transactional (Mandrill) or SendLayer\n\n- [AhaSend API + MCP vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/ahasend-vs-mandrill.md)\n- [AhaSend API + MCP vs SendLayer](https://www.anchorterminal.com/compare/ahasend-vs-sendlayer.md)\n- [Amazon SES vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/amazon-ses-vs-mandrill.md)\n- [Amazon SES vs SendLayer](https://www.anchorterminal.com/compare/amazon-ses-vs-sendlayer.md)\n- [Brevo API + MCP vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/brevo-vs-mandrill.md)\n- [Brevo API + MCP vs SendLayer](https://www.anchorterminal.com/compare/brevo-vs-sendlayer.md)\n- [Cloudflare Email Service vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-mandrill.md)\n- [Cloudflare Email Service vs SendLayer](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-sendlayer.md)\n- [Groundmail API + MCP vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/groundmail-vs-mandrill.md)\n- [Groundmail API + MCP vs SendLayer](https://www.anchorterminal.com/compare/groundmail-vs-sendlayer.md)\n- [Loops API + MCP vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/loops-vs-mandrill.md)\n- [Loops API + MCP vs SendLayer](https://www.anchorterminal.com/compare/loops-vs-sendlayer.md)\n- [MailerSend vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/mailersend-vs-mandrill.md)\n- [MailerSend vs SendLayer](https://www.anchorterminal.com/compare/mailersend-vs-sendlayer.md)\n- [Mailgun API + MCP vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/mailgun-vs-mandrill.md)\n- [Mailgun API + MCP vs SendLayer](https://www.anchorterminal.com/compare/mailgun-vs-sendlayer.md)\n- [Mailjet API + MCP vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/mailjet-vs-mandrill.md)\n- [Mailjet API + MCP vs SendLayer](https://www.anchorterminal.com/compare/mailjet-vs-sendlayer.md)\n- [MailPace vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/mailpace-vs-mandrill.md)\n- [MailPace vs SendLayer](https://www.anchorterminal.com/compare/mailpace-vs-sendlayer.md)\n- [Mailtrap Email API + MCP vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/mailtrap-vs-mandrill.md)\n- [Mailtrap Email API + MCP vs SendLayer](https://www.anchorterminal.com/compare/mailtrap-vs-sendlayer.md)\n- [Mailchimp Transactional (Mandrill) vs Postmark API + MCP](https://www.anchorterminal.com/compare/mandrill-vs-postmark.md)\n- [Mailchimp Transactional (Mandrill) vs Resend API + MCP](https://www.anchorterminal.com/compare/mandrill-vs-resend.md)\n- [Mailchimp Transactional (Mandrill) vs Twilio SendGrid](https://www.anchorterminal.com/compare/mandrill-vs-sendgrid.md)\n- [Mailchimp Transactional (Mandrill) vs SMTP2GO API + MCP](https://www.anchorterminal.com/compare/mandrill-vs-smtp2go.md)\n- [Mailchimp Transactional (Mandrill) vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/mandrill-vs-zoho-zeptomail.md)\n- [Postmark API + MCP vs SendLayer](https://www.anchorterminal.com/compare/postmark-vs-sendlayer.md)\n- [Resend API + MCP vs SendLayer](https://www.anchorterminal.com/compare/resend-vs-sendlayer.md)\n- [Twilio SendGrid vs SendLayer](https://www.anchorterminal.com/compare/sendgrid-vs-sendlayer.md)\n- [SendLayer vs SMTP2GO API + MCP](https://www.anchorterminal.com/compare/sendlayer-vs-smtp2go.md)\n- [SendLayer vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/sendlayer-vs-zoho-zeptomail.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "attributionRequired": true, "credit": "CC BY 4.0, credit Anchor Terminal and link the page or API address you took it from (https://www.anchorterminal.com/terms/#data)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-11-07", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.7", "openapi": "https://www.anchorterminal.com/openapi.json", "preview": false, "run": "2026-10-01", "runLabel": "October 2026 research run", "terms": "https://www.anchorterminal.com/terms/#data" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "Mailchimp Transactional (Mandrill) vs SendLayer", "url": "" } ], "description": "Mailchimp Transactional scores 61.5 (C) to SendLayer's 47.7 (D) for sending email. Prices, MCP, x402, uptime and agent notes side by side.", "facts": [ "Mailchimp Transactional (Mandrill) C 61.5", "SendLayer D 47.7", "scores" ], "h1": "Mailchimp Transactional (Mandrill) vs SendLayer", "image": "https://www.anchorterminal.com/assets/og/default.png", "path": "/compare/mandrill-vs-sendlayer", "published": "2026-10-01", "section": "tools", "title": "Mailchimp Transactional vs SendLayer for AI agents (2026)", "toc": null, "updated": "2026-11-07", "url": "https://www.anchorterminal.com/compare/mandrill-vs-sendlayer" }, "tokens": { "markdown": 5150, "slim": 2980 }, "version": 1 }