{ "data": { "a": { "slug": "mailpace", "name": "MailPace", "vendor": "OhMySMTP Ltd", "vendorUrl": "https://mailpace.com", "kind": "http-api", "category": "email", "summary": "MailPace is a UK transactional email service, formerly OhMySMTP, hosted in the EU. It sends mail through an HTTPS API or SMTP, turns inbound mail into webhooks and has a Domains and Email Status API.", "url": "https://www.anchorterminal.com/tools/mailpace", "markdownUrl": "https://www.anchorterminal.com/tools/mailpace.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/mailpace.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/mailpace.json", "dns": "mailpace.grade.anchorterminal.com", "repo": "https://github.com/mailpace/mailpace-mcp", "transports": [ "http" ], "packages": [ { "registry": "npm", "name": "@mailpace/mailpace.js" } ], "auth": "api-key", "authNotes": "Each domain has its own server token, sent in the `MailPace-Server-Token` header, which can send from that domain and read its email status. An organisation token in `MailPace-Organization-Token` manages domains and domain tokens through the Domains API, including revoking them. Both are made in the dashboard after a browser signup.", "pricing": "paid", "pricingNotes": "$10 a month includes 10,000 emails sent or received, then $1 per 1,000, per the Paddle prices the pricing page loads and the comparison pages ($100 for 100,000, $1,000 for 1 million). A free plan of up to 100 emails a month is given on request by email. Paddle is the merchant of record; card, PayPal, Apple Pay or Google Pay.", "priceSummary": "$10 / mo", "where": "local", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the docs repository, the pricing page or the MCP server source (checked 2026-11-06). Payment is by Paddle subscription; the FAQ says crypto isn't accepted.", "endpoints": [] }, "toolCount": 12, "popularity": { "githubStars": 1, "npmWeekly": 207, "pypiWeekly": null, "asOf": "2026-11-06" }, "docsUrl": "https://docs.mailpace.com/", "capabilities": [ "email.send", "email.inbound", "email.domains", "email.analytics" ], "tags": [ "hosted", "closed-source", "smtp", "webhooks", "idempotency", "status-page", "sla", "eu", "mcp", "typescript", "ruby", "go", "php" ], "lastRelease": "2026-10-22", "graded": true, "anchor": { "graded": true, "score": 58.4, "grade": "C", "agentReady": false, "rank": 750, "ranked": true, "rankOf": 1486, "categoryRank": 17, "methodology": "0.7", "run": "2026-10-01", "scores": { "ergonomics": 71, "maintenance": 65, "payments": 25, "reliability": 70, "schema": 54, "security": 50, "transparency": 75 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-11-06" }, "negative": 0, "verdict": "A small transactional sender with idempotent sends, signed webhooks, a 99% availability promise in its terms and a public Upptime status record. There is no OpenAPI spec, no published rate limit, no llms.txt, and its MCP server was rewritten on 4 November 2026 but isn't on npm or in the MCP registry yet.", "bestFor": "Low-volume transactional mail from EU-hosted infrastructure with idempotent sends and no tracking.", "strengths": [ "Sends accept an `Idempotency-Key` header kept for 24 hours, so a retry after a timeout doesn't send twice", "Per-domain server tokens limit a leaked key to one domain, and organisation tokens can create and revoke them by API", "Webhooks are signed with Ed25519 and inbound mail is retried five times before it fails", "Status page on Upptime with GitHub issues as incident reports, and a 99% monthly availability promise with credits in the terms", "Sub-processors and their locations are listed, and mail is kept 30 days plus 7 in backups per the DPA" ], "weaknesses": [ "No OpenAPI spec, llms.txt or Markdown docs for agents; the reference is Docusaurus pages", "Rate limits aren't published; the docs say they vary by organisation age, plan and history", "No free plan without emailing support, and the paid plan starts at $10 a month", "MCP server 2.0.0 exists only in the repository; npm and the MCP registry had nothing for it on 6 November 2026", "No security.txt, disclosure policy or certification found" ], "agentNotes": [ "Send a UUID in `Idempotency-Key` on every `POST /api/v1/send`, and reuse it on a retry; keys last 24 hours and are tied to one token", "Use the server token of the sending domain, since the From domain must match the token's domain or the API returns 403", "On 429 `You are sending emails too quickly` back off; no Retry-After is documented", "Send only transactional mail; marketing and bulk newsletters are prohibited by the docs and terms", "Read delivery with `GET /api/v1/domains/:domain_id/emails/:id` using the id the send returned" ], "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": 58.4 } ], "editorialScores": { "ergonomics": 71, "maintenance": 65, "payments": 25, "reliability": 70, "schema": 54, "security": 50, "transparency": 69 }, "provenanceScore": 81, "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": { "http": "curl https://app.mailpace.com/api/v1/send -X POST -H \"Accept: application/json\" -H \"Content-Type: application/json\" -H \"MailPace-Server-Token: $MAILPACE_TOKEN\" -H \"Idempotency-Key: $(uuidgen)\" -d '{\"from\":\"you@yourdomain.com\",\"to\":\"person@example.com\",\"subject\":\"Hello\",\"textbody\":\"Hello\"}'" }, "letme": { "capability": "https://letme.dev/email.send", "tool": "https://letme.dev/mailpace" }, "area": "communication", "unitPrices": [ { "item": "Scaling plan", "unit": "month", "usd": 10, "note": "includes 10,000 emails sent or received" }, { "item": "Emails beyond 10,000", "unit": "1k-emails", "usd": 1 } ], "provenance": { "legalEntity": "OhMySMTP Ltd", "domain": "mailpace.com", "domainRegistered": "2022-01-10", "endpointOnVendorDomain": true, "terms": "https://mailpace.com/terms", "privacy": "https://mailpace.com/privacy", "statusPage": "https://status.mailpace.com", "changelog": "https://mailpace.com/category/changelog", "securityTxt": "none", "checked": "2026-11-06", "notes": [ "The terms and privacy policy name OhMySMTP Ltd, incorporated in England and Wales, company number 13200428. Companies House lists two active directors.", "Terms last updated 9 January 2026, privacy policy 30 August 2026, DPA updated in October 2026 per the landing repository.", "mailpace.com/robots.txt allows all paths. The terms contain no clause on automated access to the website beyond the usual licence limits.", "RDAP gives mailpace.com a registration date of 10 January 2022; the service ran as OhMySMTP before that.", "/.well-known/security.txt returns 404 on mailpace.com and app.mailpace.com." ], "score": 81 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/mailpace.json", "live": { "slug": "mailpace", "vendorStatus": { "page": "https://status.mailpace.com", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-11-07T04:48:01.553362214Z" }, "versions": [ { "registry": "npm", "name": "@mailpace/mailpace.js", "version": "0.1.3", "seenAt": "2026-11-06T23:42:02.752996422Z" } ], "githubStars": 1, "npmWeekly": 207, "securityTxt": { "url": "https://mailpace.com/.well-known/security.txt", "state": "none", "checkedAt": "2026-11-07T16:01:07.630537329Z" }, "pages": [ { "url": "https://mailpace.com/category/changelog", "kind": "changelog", "status": 200, "checkedAt": "2026-11-07T14:13:40.841899008Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "38f92a159d1b" }, { "url": "https://mailpace.com/privacy", "kind": "privacy", "status": 200, "checkedAt": "2026-11-07T14:13:45.28058492Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "e6b0fea49c1d" }, { "url": "https://mailpace.com/terms", "kind": "terms", "status": 200, "checkedAt": "2026-11-07T14:13:45.480605157Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "24f1eed01dad" } ], "updatedAt": "2026-11-07T16:01:07.630537329Z" } }, "answer": "MailPace scores 58.4 (C) on agent readiness against SendLayer's 47.7 (D), and leads in 6 of 7 scored categories. SendLayer leads on schema \u0026 documentation.", "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": 1135, "ranked": true, "rankOf": 1486, "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": "2026-11-07T18:20:53.661767075Z", "lastOk": true, "lastStatus": 405, "lastMs": 337, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 332, "p95ms24h": 423, "samples24h": 200, "samples30d": 200, "days": [ { "date": "2026-11-06", "probes": 13, "ok": 13 }, { "date": "2026-11-07", "probes": 187, "ok": 187 } ] }, "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": "2026-11-07T18:20:53.661767075Z" } }, "edges": [ { "by": 26, "category": "transparency", "leads": "mailpace", "name": "Transparency \u0026 trust", "reasons": { "a": "Closed hosted service under terms that name OhMySMTP Ltd with its company number. The MCP server, SDKs, landing site and status page are MIT (18 of 30). The privacy policy (30 August 2026), the pricing page and the DPA agree on retention, 30 days in the dashboard and 7 more in backups, 37 days at most (25 of 30). The API reference promises an old version runs until a published end-of-life date, and the terms list dated changes. The terms also say changes apply immediately (8 of 20). Sub-processors listed with purpose and location, Freethought hosting in the EU, Hetzner backups in Germany, AppSignal in Amsterdam, Paddle in the UK and Tutanota in Germany (18 of 20). Total 69.", "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": 75, "b": 49 } }, { "by": 25, "category": "maintenance", "leads": "mailpace", "name": "Maintenance \u0026 community", "reasons": { "a": "Email Status API documented on 22 October 2026, and the MCP server rewritten as 2.0.0 on 4 November 2026, two days before this check (30). In the 90 days from 8 August, the Q3 changelog post of 31 August, the Email Status docs of 22 October, a mailpace-rails push on 17 October and the MCP rewrite, but only one changelog post (15 of 20). A closed service with email support. Three pull requests to the MCP repository from 2025 have no reply (8 of 15). Not in the official MCP registry (search for mailpace returned nothing on 6 November). The Node library was last pushed in October 2024 and Go in January 2024, while mailpace-rails is current (7 of 15). The MCP server gained CI with tests on 4 November; the older SDKs weren't checked for CI (5 of 10). Total 65.", "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": 65, "b": 40 } }, { "by": 22, "category": "reliability", "leads": "mailpace", "name": "Reliability", "reasons": { "a": "Graded with the hosted lines. A public Upptime status page at status.mailpace.com, driven by the mailpace/status repository, with monitors for the application, SMTP, docs, blog and landing page and GitHub issues as incident reports (20). The 90 days from 8 August hold two incidents, an application outage on 22 September 2026 that the operator put down to an upstream provider returning 5xx (issue open for two minutes), and SMTP down on 2 November 2026 for about 35 minutes, which leaves SMTP at 99.65% for the week. Minor incidents only (20). No rate limit numbers are published; the docs say limits vary by organisation age, plan and history (0). A documented 429 with its message, no Retry-After or backoff guidance, and an `Idempotency-Key` on sends with written retry rules (10 of 15). The terms guarantee 99% monthly availability of the API and dashboard with a 5% credit per 30 minutes (10). The API is at v1 with no beta label (10). Total 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": 14, "category": "schema", "leads": "sendlayer", "name": "Schema \u0026 documentation", "reasons": { "a": "No OpenAPI or other machine-readable contract for the HTTPS API. The MCP server's 12 tools have typed zod inputs and output schemas, but that server isn't published yet, so partial credit (8 of 25). llms.txt answers 404 on mailpace.com and docs.mailpace.com, and no Markdown copies are served (0). The reference states what each endpoint does, and the introduction says when not to use it (transactional only, no batch, no static IPs) (12 of 20). Field tables give type, examples and required or optional, with enums for status, sort and direction and the 50-recipient cap in text (9 of 15). Examples in curl and six languages and a full table of error responses with messages, though several listed messages have a broken quote (`{\"error:\"...`) and the send reference says 30 MB where the home page says 25 MB (12 of 15). Version in the path with a promise that an old version runs until a published end-of-life date, and dated changelog posts (13 of 15). Total 54.", "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": 54, "b": 68 } }, { "by": 12, "category": "security", "leads": "mailpace", "name": "Security \u0026 auth", "reasons": { "a": "Per-domain server tokens that can only send from and read status for their domain, and an organisation token that creates, renames and revokes domain tokens through the Domains API. Tokens travel in headers only. The authentication page still tells users to contact support to regenerate a leaked token (25 of 30). No read-only token. A domain token can't touch other domains, and the unpublished MCP server has an optional recipient allowlist. No approval step on the hosted API (8 of 20). Inbound mail reaches the customer's webhook as untrusted content, and Email Status returns bounce text. The MCP README warns about prompt injection and suggests the allowlist (9 of 15). The dashboard keeps sent mail for 30 days; no log of API calls was found (6 of 15). No security.txt (404 on mailpace.com and app.mailpace.com), no disclosure policy, bug bounty, SOC 2 or ISO 27001. WebAuthn-only two-factor sign-in and Ed25519-signed webhooks are documented (2 of 20). Total 50.", "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": 50, "b": 38 } }, { "by": 9, "category": "ergonomics", "leads": "mailpace", "name": "Agent ergonomics", "reasons": { "a": "Responses are small, the send returns an id and status and Email Status returns one email (18 of 25). Only the domains list takes `limit`, `offset`, `sort` and `direction`; there is no endpoint to list or search sent mail (8 of 20). Errors are JSON with a human message and an HTTP status for each case in the documented table, with no stable error codes (14 of 20). `Idempotency-Key` on sends, kept 24 hours per token, and failed validations are not stored so they can be retried. The MCP server marks send as not idempotent and revoke as destructive (18 of 20). A send needs from, to, a subject and a body; official libraries for Node, Rails, Go and PHP transports and an SMTP route (13 of 15). Total 71.", "b": "Small responses and five MCP tools (18 of 25). Events filter by start and end date, event type and message ID, with an offset and a count (15 of 20). Errors are JSON with a numbered code and message per field, and documented (14 of 20). No idempotency key on sends, and the MCP annotations can't be read (0 of 20). A send needs from, to, subject, content type and content; official SDKs for Node, Python, PHP, Ruby and Go (15). Total 62." }, "scores": { "a": 71, "b": 62 } } ], "facts": [ { "a": "HTTP API", "b": "HTTP API", "name": "Kind" }, { "a": "OhMySMTP Ltd", "b": "SendLayer, LLC", "name": "Vendor" }, { "a": "no (local only)", "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": "12", "b": "5", "name": "Tools exposed" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "no", "b": "yes", "name": "llms.txt" }, { "a": "2026-10-22", "b": "2026-08-21", "name": "Last release" }, { "a": "2026-01-09", "b": "no date given", "name": "Terms last updated" }, { "a": "2026-08-30", "b": "no date given", "name": "Privacy policy last updated" }, { "a": "not found in the text", "b": "not found in the text", "name": "Customer content may train models" }, { "a": "yes", "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": "not found in the text", "b": "yes", "name": "Terms or service can change without notice" }, { "a": "not found in the text", "b": "not found in the text", "name": "Arbitration or class-action waiver" }, { "a": "1 stars, 207 npm/wk", "b": "113 npm/wk, 9 PyPI/wk", "name": "Popularity" } ], "faq": [ { "answer": "MailPace scores 58.4 (C) on agent readiness against SendLayer's 47.7 (D), and leads in 6 of 7 scored categories. SendLayer leads on schema \u0026 documentation.", "question": "Which is better for AI agents, MailPace or SendLayer?" }, { "answer": "Both need an API key.", "question": "Do MailPace and SendLayer need an API key?" }, { "answer": "No hosted endpoint is listed for MailPace. SendLayer has a hosted endpoint at https://mcp.sendlayer.com.", "question": "Can an agent call MailPace and SendLayer without installing anything?" } ], "goodFor": [ { "aheadOn": [ "Reliability, 70 against 48", "Agent ergonomics, 71 against 62", "Security \u0026 auth, 50 against 38", "Payments \u0026 pricing, 25 against 20", "Maintenance \u0026 community, 65 against 40", "Transparency \u0026 trust, 75 against 49" ], "also": null, "goodFor": "Low-volume transactional mail from EU-hosted infrastructure with idempotent sends and no tracking.", "slug": "mailpace", "watchFor": "No OpenAPI spec, llms.txt or Markdown docs for agents; the reference is Docusaurus pages" }, { "aheadOn": [ "Schema \u0026 documentation, 68 against 54" ], "also": [ "A hosted endpoint, with nothing to install" ], "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": null, "job": { "capability": "email.send", "name": "Sending email" }, "others": [ { "json": "https://www.anchorterminal.com/compare/ahasend-vs-mailpace.json", "title": "AhaSend API + MCP vs MailPace", "url": "https://www.anchorterminal.com/compare/ahasend-vs-mailpace" }, { "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-mailpace.json", "title": "Amazon SES vs MailPace", "url": "https://www.anchorterminal.com/compare/amazon-ses-vs-mailpace" }, { "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-mailpace.json", "title": "Brevo API + MCP vs MailPace", "url": "https://www.anchorterminal.com/compare/brevo-vs-mailpace" }, { "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-mailpace.json", "title": "Cloudflare Email Service vs MailPace", "url": "https://www.anchorterminal.com/compare/cloudflare-email-service-vs-mailpace" }, { "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-mailpace.json", "title": "Groundmail API + MCP vs MailPace", "url": "https://www.anchorterminal.com/compare/groundmail-vs-mailpace" }, { "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-mailpace.json", "title": "Loops API + MCP vs MailPace", "url": "https://www.anchorterminal.com/compare/loops-vs-mailpace" }, { "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-mailpace.json", "title": "MailerSend vs MailPace", "url": "https://www.anchorterminal.com/compare/mailersend-vs-mailpace" }, { "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-mailpace.json", "title": "Mailgun API + MCP vs MailPace", "url": "https://www.anchorterminal.com/compare/mailgun-vs-mailpace" }, { "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-mailpace.json", "title": "Mailjet API + MCP vs MailPace", "url": "https://www.anchorterminal.com/compare/mailjet-vs-mailpace" }, { "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-mailtrap.json", "title": "MailPace vs Mailtrap Email API + MCP", "url": "https://www.anchorterminal.com/compare/mailpace-vs-mailtrap" }, { "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-postmark.json", "title": "MailPace vs Postmark API + MCP", "url": "https://www.anchorterminal.com/compare/mailpace-vs-postmark" }, { "json": "https://www.anchorterminal.com/compare/mailpace-vs-resend.json", "title": "MailPace vs Resend API + MCP", "url": "https://www.anchorterminal.com/compare/mailpace-vs-resend" }, { "json": "https://www.anchorterminal.com/compare/mailpace-vs-sendgrid.json", "title": "MailPace vs Twilio SendGrid", "url": "https://www.anchorterminal.com/compare/mailpace-vs-sendgrid" }, { "json": "https://www.anchorterminal.com/compare/mailpace-vs-smtp2go.json", "title": "MailPace vs SMTP2GO API + MCP", "url": "https://www.anchorterminal.com/compare/mailpace-vs-smtp2go" }, { "json": "https://www.anchorterminal.com/compare/mailpace-vs-zoho-zeptomail.json", "title": "MailPace vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/mailpace-vs-zoho-zeptomail" }, { "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-sendlayer.json", "title": "Mailchimp Transactional (Mandrill) vs SendLayer", "url": "https://www.anchorterminal.com/compare/mandrill-vs-sendlayer" }, { "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": "mailpace", "key": "reliability", "mailpace": 70, "name": "Reliability", "sendlayer": 48, "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "by": 14, "edge": "sendlayer", "key": "schema", "mailpace": 54, "name": "Schema \u0026 documentation", "sendlayer": 68, "weight": 13 }, { "by": 9, "edge": "mailpace", "key": "ergonomics", "mailpace": 71, "name": "Agent ergonomics", "sendlayer": 62, "weight": 13 }, { "by": 12, "edge": "mailpace", "key": "security", "mailpace": 50, "name": "Security \u0026 auth", "sendlayer": 38, "weight": 14 }, { "by": 5, "edge": "mailpace", "key": "payments", "mailpace": 25, "name": "Payments \u0026 pricing", "sendlayer": 20, "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "by": 25, "edge": "mailpace", "key": "maintenance", "mailpace": 65, "name": "Maintenance \u0026 community", "sendlayer": 40, "weight": 7 }, { "by": 26, "edge": "mailpace", "key": "transparency", "mailpace": 75, "name": "Transparency \u0026 trust", "sendlayer": 49, "weight": 7 } ], "summary": "MailPace scores 58.4 (C) on agent readiness against SendLayer's 47.7 (D), and leads in 6 of 7 scored categories. SendLayer leads on schema \u0026 documentation. Both do sending email.", "tasks": null, "tutorials": [], "verdicts": { "mailpace": "A small transactional sender with idempotent sends, signed webhooks, a 99% availability promise in its terms and a public Upptime status record. There is no OpenAPI spec, no published rate limit, no llms.txt, and its MCP server was rewritten on 4 November 2026 but isn't on npm or in the MCP registry yet.", "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/mailpace-vs-sendlayer", "json": "https://www.anchorterminal.com/compare/mailpace-vs-sendlayer.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/mailpace-vs-sendlayer.md", "mcp": "https://www.anchorterminal.com/mcp", "slim": "https://www.anchorterminal.com/compare/mailpace-vs-sendlayer.min.md" }, "markdown": "MailPace scores 58.4 (C) on agent readiness against SendLayer's 47.7 (D), and leads in 6 of 7 scored categories. SendLayer leads on schema \u0026 documentation. Both do sending email.\n\n- MailPace: grade C, 58.4/100, rank #750 of 1486. Markdown https://www.anchorterminal.com/tools/mailpace.md · JSON https://www.anchorterminal.com/api/v1/tools/mailpace.json\n- SendLayer: grade D, 47.7/100, rank #1135 of 1486. 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### MailPace (C)\n\nGood for: Low-volume transactional mail from EU-hosted infrastructure with idempotent sends and no tracking.\n\nAhead on:\n- Reliability, 70 against 48\n- Agent ergonomics, 71 against 62\n- Security \u0026 auth, 50 against 38\n- Payments \u0026 pricing, 25 against 20\n- Maintenance \u0026 community, 65 against 40\n- Transparency \u0026 trust, 75 against 49\n\nWatch for: No OpenAPI spec, llms.txt or Markdown docs for agents; the reference is Docusaurus pages\n\n### SendLayer (D)\n\nGood for: Low-volume transactional mail for WordPress and small sites.\n\nAhead on:\n- Schema \u0026 documentation, 68 against 54\n\nAlso in its favour:\n- A hosted endpoint, with nothing to install\n\nWatch for: No idempotency key on sends, so a retried request can send twice\n\n\n## Why the edge\n\n### Transparency \u0026 trust: MailPace +26\n\n- MailPace (75): Closed hosted service under terms that name OhMySMTP Ltd with its company number. The MCP server, SDKs, landing site and status page are MIT (18 of 30). The privacy policy (30 August 2026), the pricing page and the DPA agree on retention, 30 days in the dashboard and 7 more in backups, 37 days at most (25 of 30). The API reference promises an old version runs until a published end-of-life date, and the terms list dated changes. The terms also say changes apply immediately (8 of 20). Sub-processors listed with purpose and location, Freethought hosting in the EU, Hetzner backups in Germany, AppSignal in Amsterdam, Paddle in the UK and Tutanota in Germany (18 of 20). Total 69.\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### Maintenance \u0026 community: MailPace +25\n\n- MailPace (65): Email Status API documented on 22 October 2026, and the MCP server rewritten as 2.0.0 on 4 November 2026, two days before this check (30). In the 90 days from 8 August, the Q3 changelog post of 31 August, the Email Status docs of 22 October, a mailpace-rails push on 17 October and the MCP rewrite, but only one changelog post (15 of 20). A closed service with email support. Three pull requests to the MCP repository from 2025 have no reply (8 of 15). Not in the official MCP registry (search for mailpace returned nothing on 6 November). The Node library was last pushed in October 2024 and Go in January 2024, while mailpace-rails is current (7 of 15). The MCP server gained CI with tests on 4 November; the older SDKs weren't checked for CI (5 of 10). Total 65.\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### Reliability: MailPace +22\n\n- MailPace (70): Graded with the hosted lines. A public Upptime status page at status.mailpace.com, driven by the mailpace/status repository, with monitors for the application, SMTP, docs, blog and landing page and GitHub issues as incident reports (20). The 90 days from 8 August hold two incidents, an application outage on 22 September 2026 that the operator put down to an upstream provider returning 5xx (issue open for two minutes), and SMTP down on 2 November 2026 for about 35 minutes, which leaves SMTP at 99.65% for the week. Minor incidents only (20). No rate limit numbers are published; the docs say limits vary by organisation age, plan and history (0). A documented 429 with its message, no Retry-After or backoff guidance, and an `Idempotency-Key` on sends with written retry rules (10 of 15). The terms guarantee 99% monthly availability of the API and dashboard with a 5% credit per 30 minutes (10). The API is at v1 with no beta label (10). Total 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### Schema \u0026 documentation: SendLayer +14\n\n- MailPace (54): No OpenAPI or other machine-readable contract for the HTTPS API. The MCP server's 12 tools have typed zod inputs and output schemas, but that server isn't published yet, so partial credit (8 of 25). llms.txt answers 404 on mailpace.com and docs.mailpace.com, and no Markdown copies are served (0). The reference states what each endpoint does, and the introduction says when not to use it (transactional only, no batch, no static IPs) (12 of 20). Field tables give type, examples and required or optional, with enums for status, sort and direction and the 50-recipient cap in text (9 of 15). Examples in curl and six languages and a full table of error responses with messages, though several listed messages have a broken quote (`{\"error:\"...`) and the send reference says 30 MB where the home page says 25 MB (12 of 15). Version in the path with a promise that an old version runs until a published end-of-life date, and dated changelog posts (13 of 15). Total 54.\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### Security \u0026 auth: MailPace +12\n\n- MailPace (50): Per-domain server tokens that can only send from and read status for their domain, and an organisation token that creates, renames and revokes domain tokens through the Domains API. Tokens travel in headers only. The authentication page still tells users to contact support to regenerate a leaked token (25 of 30). No read-only token. A domain token can't touch other domains, and the unpublished MCP server has an optional recipient allowlist. No approval step on the hosted API (8 of 20). Inbound mail reaches the customer's webhook as untrusted content, and Email Status returns bounce text. The MCP README warns about prompt injection and suggests the allowlist (9 of 15). The dashboard keeps sent mail for 30 days; no log of API calls was found (6 of 15). No security.txt (404 on mailpace.com and app.mailpace.com), no disclosure policy, bug bounty, SOC 2 or ISO 27001. WebAuthn-only two-factor sign-in and Ed25519-signed webhooks are documented (2 of 20). Total 50.\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### Agent ergonomics: MailPace +9\n\n- MailPace (71): Responses are small, the send returns an id and status and Email Status returns one email (18 of 25). Only the domains list takes `limit`, `offset`, `sort` and `direction`; there is no endpoint to list or search sent mail (8 of 20). Errors are JSON with a human message and an HTTP status for each case in the documented table, with no stable error codes (14 of 20). `Idempotency-Key` on sends, kept 24 hours per token, and failed validations are not stored so they can be retried. The MCP server marks send as not idempotent and revoke as destructive (18 of 20). A send needs from, to, a subject and a body; official libraries for Node, Rails, Go and PHP transports and an SMTP route (13 of 15). Total 71.\n- SendLayer (62): Small responses and five MCP tools (18 of 25). Events filter by start and end date, event type and message ID, with an offset and a count (15 of 20). Errors are JSON with a numbered code and message per field, and documented (14 of 20). No idempotency key on sends, and the MCP annotations can't be read (0 of 20). A send needs from, to, subject, content type and content; official SDKs for Node, Python, PHP, Ruby and Go (15). Total 62.\n\n## Score by category\n\n| Category | Weight | MailPace | SendLayer | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 70 | 48 | MailPace +22 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 54 | 68 | SendLayer +14 |\n| Agent ergonomics | 13% (16.2 this run) | 71 | 62 | MailPace +9 |\n| Security \u0026 auth | 14% (17.5 this run) | 50 | 38 | MailPace +12 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 25 | 20 | MailPace +5 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 65 | 40 | MailPace +25 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 75 | 49 | MailPace +26 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **58.4 · C** | **47.7 · D** | |\n\n## Facts side by side\n\n| Fact | MailPace | SendLayer |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | OhMySMTP Ltd | SendLayer, LLC |\n| Hosted endpoint | no (local only) | `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| Tools exposed | 12 | 5 |\n| Read-only variant documented | no | no |\n| llms.txt | no | yes |\n| Last release | 2026-10-22 | 2026-08-21 |\n| Terms last updated | 2026-01-09 | no date given |\n| Privacy policy last updated | 2026-08-30 | no date given |\n| Customer content may train models | not found in the text | not found in the text |\n| Terms restrict automated access | yes | 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 | not found in the text | yes |\n| Arbitration or class-action waiver | not found in the text | not found in the text |\n| Popularity | 1 stars, 207 npm/wk | 113 npm/wk, 9 PyPI/wk |\n\n## Verdicts\n\n**MailPace.** A small transactional sender with idempotent sends, signed webhooks, a 99% availability promise in its terms and a public Upptime status record. There is no OpenAPI spec, no published rate limit, no llms.txt, and its MCP server was rewritten on 4 November 2026 but isn't on npm or in the MCP registry yet.\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### MailPace\n\n1. Send a UUID in `Idempotency-Key` on every `POST /api/v1/send`, and reuse it on a retry; keys last 24 hours and are tied to one token\n2. Use the server token of the sending domain, since the From domain must match the token's domain or the API returns 403\n3. On 429 `You are sending emails too quickly` back off; no Retry-After is documented\n4. Send only transactional mail; marketing and bulk newsletters are prohibited by the docs and terms\n5. Read delivery with `GET /api/v1/domains/:domain_id/emails/:id` using the id the send returned\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, MailPace or SendLayer?\n\nMailPace scores 58.4 (C) on agent readiness against SendLayer's 47.7 (D), and leads in 6 of 7 scored categories. SendLayer leads on schema \u0026 documentation.\n\n### Do MailPace and SendLayer need an API key?\n\nBoth need an API key.\n\n### Can an agent call MailPace and SendLayer without installing anything?\n\nNo hosted endpoint is listed for MailPace. SendLayer has a hosted endpoint at https://mcp.sendlayer.com.\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/mailpace-vs-sendlayer.json, and with the fewest tokens: https://www.anchorterminal.com/compare/mailpace-vs-sendlayer.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"mailpace\", \"b\": \"sendlayer\"}`. From a terminal: `anchor compare mailpace sendlayer`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/mailpace.json and https://www.anchorterminal.com/api/v1/tools/sendlayer.json\n\n## Other comparisons with MailPace or SendLayer\n\n- [AhaSend API + MCP vs MailPace](https://www.anchorterminal.com/compare/ahasend-vs-mailpace.md)\n- [AhaSend API + MCP vs SendLayer](https://www.anchorterminal.com/compare/ahasend-vs-sendlayer.md)\n- [Amazon SES vs MailPace](https://www.anchorterminal.com/compare/amazon-ses-vs-mailpace.md)\n- [Amazon SES vs SendLayer](https://www.anchorterminal.com/compare/amazon-ses-vs-sendlayer.md)\n- [Brevo API + MCP vs MailPace](https://www.anchorterminal.com/compare/brevo-vs-mailpace.md)\n- [Brevo API + MCP vs SendLayer](https://www.anchorterminal.com/compare/brevo-vs-sendlayer.md)\n- [Cloudflare Email Service vs MailPace](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-mailpace.md)\n- [Cloudflare Email Service vs SendLayer](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-sendlayer.md)\n- [Groundmail API + MCP vs MailPace](https://www.anchorterminal.com/compare/groundmail-vs-mailpace.md)\n- [Groundmail API + MCP vs SendLayer](https://www.anchorterminal.com/compare/groundmail-vs-sendlayer.md)\n- [Loops API + MCP vs MailPace](https://www.anchorterminal.com/compare/loops-vs-mailpace.md)\n- [Loops API + MCP vs SendLayer](https://www.anchorterminal.com/compare/loops-vs-sendlayer.md)\n- [MailerSend vs MailPace](https://www.anchorterminal.com/compare/mailersend-vs-mailpace.md)\n- [MailerSend vs SendLayer](https://www.anchorterminal.com/compare/mailersend-vs-sendlayer.md)\n- [Mailgun API + MCP vs MailPace](https://www.anchorterminal.com/compare/mailgun-vs-mailpace.md)\n- [Mailgun API + MCP vs SendLayer](https://www.anchorterminal.com/compare/mailgun-vs-sendlayer.md)\n- [Mailjet API + MCP vs MailPace](https://www.anchorterminal.com/compare/mailjet-vs-mailpace.md)\n- [Mailjet API + MCP vs SendLayer](https://www.anchorterminal.com/compare/mailjet-vs-sendlayer.md)\n- [MailPace vs Mailtrap Email API + MCP](https://www.anchorterminal.com/compare/mailpace-vs-mailtrap.md)\n- [MailPace vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/mailpace-vs-mandrill.md)\n- [MailPace vs Postmark API + MCP](https://www.anchorterminal.com/compare/mailpace-vs-postmark.md)\n- [MailPace vs Resend API + MCP](https://www.anchorterminal.com/compare/mailpace-vs-resend.md)\n- [MailPace vs Twilio SendGrid](https://www.anchorterminal.com/compare/mailpace-vs-sendgrid.md)\n- [MailPace vs SMTP2GO API + MCP](https://www.anchorterminal.com/compare/mailpace-vs-smtp2go.md)\n- [MailPace vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/mailpace-vs-zoho-zeptomail.md)\n- [Mailtrap Email API + MCP vs SendLayer](https://www.anchorterminal.com/compare/mailtrap-vs-sendlayer.md)\n- [Mailchimp Transactional (Mandrill) vs SendLayer](https://www.anchorterminal.com/compare/mandrill-vs-sendlayer.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": "MailPace vs SendLayer", "url": "" } ], "description": "MailPace scores 58.4 (C) to SendLayer's 47.7 (D) for sending email. Prices, MCP, x402, uptime and agent notes side by side.", "facts": [ "MailPace C 58.4", "SendLayer D 47.7", "scores" ], "h1": "MailPace vs SendLayer", "image": "https://www.anchorterminal.com/assets/og/default.png", "path": "/compare/mailpace-vs-sendlayer", "published": "2026-10-01", "section": "tools", "title": "MailPace vs SendLayer for AI agents in 2026: scores and prices", "toc": null, "updated": "2026-11-07", "url": "https://www.anchorterminal.com/compare/mailpace-vs-sendlayer" }, "tokens": { "markdown": 4700, "slim": 2780 }, "version": 1 }