{ "data": { "a": { "slug": "postmark", "name": "Postmark API + MCP", "vendor": "Postmark (ActiveCampaign)", "vendorUrl": "https://postmarkapp.com", "kind": "http-api", "category": "email", "summary": "Transactional email API with separate broadcast streams, templates, inbound parsing and bounce handling.", "url": "https://www.anchorterminal.com/tools/postmark", "markdownUrl": "https://www.anchorterminal.com/tools/postmark.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/postmark.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/postmark.json", "repo": "https://github.com/ActiveCampaign/postmark-mcp", "license": "MIT", "transports": [ "http", "stdio" ], "remoteUrl": "https://api.postmarkapp.com", "packages": [ { "registry": "npm", "name": "postmark" }, { "registry": "npm", "name": "@activecampaign/postmark-mcp" } ], "auth": "api-key", "authNotes": "Server API token in the `X-Postmark-Server-Token` header for sending and per-server calls, and a separate `X-Postmark-Account-Token` for account-level calls. The token `POSTMARK_API_TEST` accepts requests without sending. The MCP server reads the server token from `POSTMARK_SERVER_TOKEN`.", "pricing": "freemium", "pricingNotes": "Free Developer plan with 100 emails a month, no overages and no expiry. At 10,000 emails a month Basic is $15, Pro $16.50 and Platform $18, with overage $1.80, $1.30 and $1.20 per 1,000. Pro at 125,000 is $126.50 and at 1,500,000 is $852.50. Sent and received emails both count. Dedicated IPs $50 a month from 300,000 emails a month, DMARC monitoring $14 a month per domain (https://postmarkapp.com/pricing).", "priceSummary": "$15 / mo", "where": "both", "x402": { "level": "no", "evidence": "No x402 support in docs, pricing or MCP README (checked 2026-09-30).", "endpoints": [] }, "toolCount": 24, "popularity": { "githubStars": 57, "npmWeekly": 1281479, "pypiWeekly": null, "asOf": "2026-09-30" }, "docsUrl": "https://postmarkapp.com/developer", "llmsTxt": "https://postmarkapp.com/llms.txt", "capabilities": [ "email.send", "email.inbound", "email.templates", "email.domains", "email.analytics", "email.marketing" ], "tags": [ "hosted", "freemium", "no-card", "mcp", "llms-txt", "typescript", "webhooks" ], "lastRelease": "2026-08-12", "graded": true, "anchor": { "graded": true, "score": 66.5, "grade": "B", "agentReady": false, "rank": 235, "ranked": true, "rankOf": 722, "categoryRank": 6, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 79, "maintenance": 65, "payments": 40, "reliability": 60, "schema": 81, "security": 63, "transparency": 77 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": 0, "verdict": "24 MCP tools, all with readOnlyHint, destructiveHint and idempotentHint, and descriptions that point to alternatives. No OpenAPI spec and no published request-rate limit.", "bestFor": "Transactional mail where deliverability and a small, well-annotated MCP matter more than a free tier.", "strengths": [ "24 MCP tools, all with readOnlyHint, destructiveHint and idempotentHint, and descriptions that point to alternatives", "Prompt-injection guidance and a webhook URL allowlist in the MCP README", "45-day retention by default, two named subprocessors and a DPA in the terms", "Per-1,000 overage rates published for every plan", "IP allowlisting for API sending since 27 August 2026" ], "weaknesses": [ "No OpenAPI spec and no published request-rate limit", "Manual account approval before sending outside your own domains", "No SOC 2, ISO 27001, disclosure policy or security.txt found for Postmark itself", "Webhooks aren't HMAC-signed", "The MCP server runs locally only and its repository has no CI" ], "agentNotes": [ "Install @activecampaign/postmark-mcp, never the unscoped postmark-mcp package", "Use the token `POSTMARK_API_TEST` to check a payload without sending", "Set `MessageStream` to `outbound` for transactional mail and a broadcast stream for bulk", "Set `WEBHOOK_URL_ALLOWLIST` so a misled createWebhook call can't send events to someone else's server", "Keep `count + offset` under 10,000 on message and bounce searches" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 2, "avgRating": 3, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "B", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 66.5 } ], "editorialScores": { "ergonomics": 79, "maintenance": 65, "payments": 40, "reliability": 60, "schema": 81, "security": 63, "transparency": 69 }, "provenanceScore": 85 }, "connect": { "http": "curl https://api.postmarkapp.com/email -H \"Accept: application/json\" \\\n -H \"Content-Type: application/json\" -H \"X-Postmark-Server-Token: $POSTMARK_SERVER_TOKEN\" \\\n -d '{\"From\":\"sender@example.com\",\"To\":\"receiver@example.com\",\"Subject\":\"Hello\",\"TextBody\":\"Hello\",\"MessageStream\":\"outbound\"}'", "config": { "mcpServers": { "postmark": { "args": [ "-y", "@activecampaign/postmark-mcp" ], "command": "npx", "env": { "DEFAULT_MESSAGE_STREAM": "outbound", "DEFAULT_SENDER_EMAIL": "${DEFAULT_SENDER_EMAIL}", "POSTMARK_SERVER_TOKEN": "${POSTMARK_SERVER_TOKEN}" } } } } }, "letme": { "capability": "https://letme.dev/email.send", "tool": "https://letme.dev/postmark" }, "area": "communication", "unitPrices": [ { "item": "Basic 10k", "unit": "month", "usd": 15, "note": "10,000 emails" }, { "item": "Pro 10k", "unit": "month", "usd": 16.5, "note": "10,000 emails" }, { "item": "Platform 10k", "unit": "month", "usd": 18, "note": "10,000 emails" }, { "item": "Pro 125k", "unit": "month", "usd": 126.5, "note": "125,000 emails" }, { "item": "Overage on Basic", "unit": "1k-emails", "usd": 1.8 }, { "item": "Overage on Pro", "unit": "1k-emails", "usd": 1.3 }, { "item": "Overage on Platform", "unit": "1k-emails", "usd": 1.2 }, { "item": "Dedicated IP", "unit": "month", "usd": 50, "note": "per IP, from 300,000 emails a month" } ], "provenance": { "legalEntity": "AC PM, LLC", "domain": "postmarkapp.com", "domainRegistered": "2009-05-25", "endpointOnVendorDomain": true, "terms": "https://postmarkapp.com/terms-of-service", "privacy": "https://www.activecampaign.com/legal/privacy-policy", "statusPage": "https://status.postmarkapp.com", "changelog": "https://postmarkapp.com/updates", "securityTxt": "none", "checked": "2026-09-30", "notes": [ "AC PM, LLC is ActiveCampaign's Postmark entity. postmarkapp.com/privacy-policy redirects to ActiveCampaign's privacy policy." ], "score": 85 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/postmark.json", "live": { "slug": "postmark", "probe": { "target": "https://api.postmarkapp.com", "method": "get", "lastAt": "2026-10-08T19:52:59.535791994Z", "lastOk": true, "lastStatus": 200, "lastMs": 650, "authRequired": false, "uptime24h": 100, "uptime30d": 99.63, "p50ms24h": 590, "p95ms24h": 727, "samples24h": 272, "samples30d": 2143, "days": [ { "date": "2026-09-30", "probes": 35, "ok": 35 }, { "date": "2026-10-01", "probes": 276, "ok": 276 }, { "date": "2026-10-02", "probes": 248, "ok": 248 }, { "date": "2026-10-03", "probes": 271, "ok": 271 }, { "date": "2026-10-04", "probes": 272, "ok": 265 }, { "date": "2026-10-05", "probes": 272, "ok": 272 }, { "date": "2026-10-06", "probes": 272, "ok": 271 }, { "date": "2026-10-07", "probes": 272, "ok": 272 }, { "date": "2026-10-08", "probes": 225, "ok": 225 } ] }, "vendorStatus": { "page": "https://status.postmarkapp.com", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-08T19:39:04.74603919Z" }, "versions": [ { "registry": "github", "name": "ActiveCampaign/postmark-mcp", "version": "v2.1.1", "released": "2026-07-13", "seenAt": "2026-10-08T16:26:14.34528549Z" }, { "registry": "npm", "name": "@activecampaign/postmark-mcp", "version": "2.1.1", "seenAt": "2026-10-08T16:26:13.064671382Z" }, { "registry": "npm", "name": "postmark", "version": "5.1.0", "seenAt": "2026-10-08T16:26:12.116674057Z" } ], "githubStars": 57, "npmWeekly": 1396221, "securityTxt": { "url": "https://postmarkapp.com/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-08T15:39:01.582221748Z" }, "llmsTxt": { "url": "https://postmarkapp.com/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-08T14:00:47.172289518Z" }, "domain": { "domain": "postmarkapp.com", "registered": "2009-05-25", "source": "https://rdap.verisign.com/com/v1/domain/postmarkapp.com", "checkedAt": "2026-10-04T13:05:40.955344563Z" }, "pages": [ { "url": "https://postmarkapp.com/updates", "kind": "changelog", "status": 200, "checkedAt": "2026-10-08T18:23:18.086154534Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "66f896f3e4fd" }, { "url": "https://postmarkapp.com/pricing", "kind": "pricing", "status": 200, "checkedAt": "2026-10-08T18:23:13.944428468Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "7df8d73d2376" }, { "url": "https://www.activecampaign.com/legal/privacy-policy", "kind": "privacy", "status": 200, "checkedAt": "2026-10-07T18:10:31.997529995Z", "changedAt": "2026-10-02T15:25:06.170575042Z", "fingerprint": "3ba14f859de2" }, { "url": "https://postmarkapp.com/terms-of-service", "kind": "terms", "status": 200, "checkedAt": "2026-10-08T18:23:16.207518846Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "92e20985dde5" } ], "updatedAt": "2026-10-08T19:52:59.535791994Z" } }, "answer": "Postmark API + MCP scores 66.5 (B) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 3 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on security \u0026 auth, maintenance \u0026 community and transparency \u0026 trust.", "b": { "slug": "zoho-zeptomail", "name": "Zoho CPaaS (formerly ZeptoMail)", "vendor": "Zoho Corporation", "vendorUrl": "https://www.zoho.com/cpaas/", "kind": "http-api", "category": "email", "summary": "Transactional email service from Zoho, renamed from ZeptoMail to Zoho CPaaS in September 2026. It sends application email through a REST API or SMTP relay, with templates, domain management, suppression lists, logs and webhooks.", "url": "https://www.anchorterminal.com/tools/zoho-zeptomail", "markdownUrl": "https://www.anchorterminal.com/tools/zoho-zeptomail.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/zoho-zeptomail.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/zoho-zeptomail.json", "license": "Proprietary service under the Zoho CPaaS terms of use. The Node SDK on npm is MIT", "transports": [ "http" ], "remoteUrl": "https://cpaas.zoho.com/v1.1", "packages": [ { "registry": "npm", "name": "zeptomail" } ], "auth": "mixed", "authNotes": "Sending takes a send key in the `Authorization` header with the prefix Zoho-enczapikey. Each Agent has its own keys, one set per channel, copied from the console's SMTP/API tab or created and deleted by API. Logs, domains, templates, agents and suppression lists take a Zoho OAuth 2.0 access token (authorisation code grant, one-hour tokens, refresh tokens) with per-resource scopes. Access is self-serve, but every new account passes a manual review that the docs say takes two business days.", "pricing": "usage", "pricingNotes": "$2.50 per email credit of 10,000 emails ($0.25 per 1,000), valid six months, counted per recipient. The first credit is free, and a sandbox Agent accepts 10,000 test emails a day without sending them. No monthly plan. Credits can be bought only after the account review. Dedicated IP $30 a month, billed annually. Prices are filled in by script from a public JSON file (https://www.zoho.com/cpaas/pricing.html).", "priceSummary": "$30 / mo", "where": "hosted", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the API docs, the OpenAPI file or the pricing page (checked 2026-10-08).", "endpoints": [] }, "toolCount": null, "popularity": { "githubStars": null, "npmWeekly": 40110, "pypiWeekly": null, "asOf": "2026-10-08" }, "docsUrl": "https://www.zoho.com/cpaas/help/api/api-home.html", "llmsTxt": "https://www.zoho.com/cpaas/llms.txt", "openapi": "https://www.zohowebstatic.com/sites/zweb/json/api/cpaas/oas.json", "capabilities": [ "email.send", "email.templates", "email.domains", "email.analytics" ], "tags": [ "hosted", "usage", "openapi", "llms-txt", "oauth", "smtp", "webhooks", "sandbox", "typescript", "status-page", "bug-bounty", "soc2" ], "graded": true, "anchor": { "graded": true, "score": 61.8, "grade": "C", "agentReady": false, "rank": 356, "ranked": true, "rankOf": 722, "categoryRank": 10, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 55, "maintenance": 74, "payments": 40, "reliability": 41, "schema": 78, "security": 76, "transparency": 82 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-08" }, "negative": 0, "verdict": "A public OpenAPI 3.0 file covers all 42 operations, and each Agent has its own send-only key. Email costs $2.50 per 10,000 with the first credit free. No API rate limit, 429 handling, idempotency key or SLA was found in the reviewed documentation, and new accounts wait for a manual review.", "bestFor": "Low-volume transactional senders who want prepaid credits without a monthly plan, and teams already on Zoho.", "strengths": [ "Public OpenAPI 3.0.3 file with 42 operations, plus llms.txt and a Markdown copy of every help page", "Send keys are per Agent and per channel and can only send. Management calls use OAuth with READ, CREATE, UPDATE and DELETE scopes per resource", "Published price of $2.50 per credit of 10,000 emails, valid six months, with the first credit free", "IP allow lists for sending, the REST API and the web console, and activity logs kept for one year", "The terms commit to a six-month deprecation period for a retired API version" ], "weaknesses": [ "No API rate limit, 429 behaviour or Retry-After was found in the reviewed documentation or the OpenAPI file", "No idempotency key on send. `client_reference` is a tracking label only", "Every new account is reviewed by Zoho staff, which the docs say takes two business days, before credits can be bought", "The only official SDK found is the Node package, last published on 29 May 2026 and still named zeptomail", "The OAuth guide puts the client secret and refresh token in the token URL's query string", "No inbound email, and no SLA was found" ], "agentNotes": [ "Call the base URL for the account's region (cpaas.zoho.com, .eu, .in, .com.au, .jp or .com.cn). A key from one region fails on another", "Send with `Authorization: Zoho-enczapikey \u003ckey\u003e`. Logs, domains, templates, agents and suppressions need a Zoho OAuth token as `Authorization: Zoho-oauthtoken \u003ctoken\u003e`", "Post OAuth client secrets and refresh tokens in the request body, not the query string the guide shows, so they stay out of logs", "Don't retry a timed-out send blindly. There is no idempotency key, so look the message up by `client_reference` in the email logs first", "Count one email per recipient, including cc and bcc, and keep each address field to 500 entries and each attachment to 15 MB", "Use a sandbox Agent for tests. It accepts up to 10,000 emails a day and sends none of them" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "C", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 61.8 } ], "editorialScores": { "ergonomics": 55, "maintenance": 74, "payments": 40, "reliability": 41, "schema": 78, "security": 76, "transparency": 69 }, "provenanceScore": 94 }, "connect": { "install": "npm install zeptomail", "http": "curl --request POST --url https://cpaas.zoho.com/v1.1/email \\\n --header 'Authorization: Zoho-enczapikey REPLACE_WITH_YOUR_KEY' \\\n --header 'content-type: application/json' \\\n --data '{\"from\":{\"address\":\"hello@yourapp.com\",\"name\":\"Your App\"},\"to\":[{\"email_address\":{\"address\":\"user@example.com\",\"name\":\"User\"}}],\"subject\":\"Test Email\",\"htmlbody\":\"\u003cp\u003eTest email sent successfully.\u003c/p\u003e\"}'" }, "letme": { "capability": "https://letme.dev/email.send", "tool": "https://letme.dev/zoho-zeptomail" }, "sameCompany": [ "zoho-books", "zoho-crm", "zoho-recruit", "zoho-people" ], "area": "communication", "unitPrices": [ { "item": "Email credit", "unit": "1k-emails", "usd": 0.25, "note": "$2.50 per credit of 10,000 emails, valid six months, counted per recipient. First credit free" }, { "item": "Dedicated IP", "unit": "month", "usd": 30, "note": "Billed annually, some data centres only" } ], "provenance": { "legalEntity": "Zoho Corporation", "domain": "zoho.com", "domainRegistered": "2004-01-16", "endpointOnVendorDomain": true, "terms": "https://www.zoho.com/cpaas/terms.html", "privacy": "https://www.zoho.com/privacy.html", "statusPage": "https://us.zohostatus.com/", "changelog": "https://www.zoho.com/cpaas/whats-new.html", "securityTxt": "valid", "checked": "2026-10-08", "notes": [ "The Zoho CPaaS terms of use name the contracting party as the Zoho entity for the customer's region. That is Zoho Corporation for the United States and Zoho Corporation Private Limited for India (https://www.zoho.com/legal/zoho-contracting-entities.html).", "The privacy field points at Zoho's privacy policy, last updated 22 December 2025, whose Part II covers the data customers process through Zoho services. Zoho CPaaS has no privacy policy of its own.", "status.zoho.com redirects to us.zohostatus.com, which lists Zepto Mail, Zepto Mail-SMTP and Zepto Mail-SMTP (PORT:465) under the old name. Other regions have their own status sites.", "www.zoho.com/.well-known/security.txt names security@zohocorp.com and the bug bounty, and expires on 30 June 2028. cpaas.zoho.com/.well-known/security.txt returns 403.", "RDAP for zoho.com gives a registration date of 2004-01-16." ], "score": 94 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/zoho-zeptomail.json", "live": { "slug": "zoho-zeptomail", "probe": { "target": "https://cpaas.zoho.com/v1.1", "method": "get", "lastAt": "2026-10-08T19:53:07.788146603Z", "lastOk": true, "lastStatus": 403, "lastMs": 459, "lastNote": "asks for credentials", "authRequired": true, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 433, "p95ms24h": 590, "samples24h": 27, "samples30d": 27, "days": [ { "date": "2026-10-08", "probes": 27, "ok": 27 } ] }, "vendorStatus": { "page": "https://us.zohostatus.com", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-08T19:39:22.469628831Z" }, "pages": [ { "url": "https://www.zoho.com/cpaas/whats-new.html", "kind": "changelog", "status": 200, "checkedAt": "2026-10-08T18:31:56.469057518Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "7bf282bb5347" }, { "url": "https://www.zoho.com/cpaas/pricing.html", "kind": "pricing", "status": 200, "checkedAt": "2026-10-08T18:31:52.435007702Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "b4b0b9f913a0" }, { "url": "https://www.zoho.com/cpaas/terms.html", "kind": "terms", "status": 200, "checkedAt": "2026-10-08T18:31:54.470399117Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "a4fd5ba82732" } ], "updatedAt": "2026-10-08T19:53:07.788146603Z" } }, "facts": [ { "a": "HTTP API", "b": "HTTP API", "name": "Kind" }, { "a": "Postmark (ActiveCampaign)", "b": "Zoho Corporation", "name": "Vendor" }, { "a": "https://api.postmarkapp.com", "b": "https://cpaas.zoho.com/v1.1", "name": "Hosted endpoint" }, { "a": "HTTP, stdio", "b": "HTTP", "name": "Transports" }, { "a": "API key", "b": "OAuth or key", "name": "Auth" }, { "a": "Freemium", "b": "Pay per use", "name": "Pricing" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "MIT", "b": "Proprietary service under the Zoho CPaaS terms of use. The Node SDK on npm is MIT", "name": "Licence" }, { "a": "24", "b": "none", "name": "Tools exposed" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "yes", "name": "llms.txt" }, { "a": "2026-08-12", "b": "none", "name": "Last release" }, { "a": "2024-12-10", "b": "no date given", "name": "Terms last updated" }, { "a": "2026-10-01", "b": "2025-12-22", "name": "Privacy policy last updated" }, { "a": "yes", "b": "yes", "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": "not found in the text", "name": "Terms or service can change without notice" }, { "a": "yes", "b": "not found in the text", "name": "Arbitration or class-action waiver" }, { "a": "57 stars, 1.3M npm/wk", "b": "40k npm/wk", "name": "Popularity" }, { "a": "3/5 (2)", "b": "none", "name": "Agent reviews" } ], "faq": [ { "answer": "Postmark API + MCP scores 66.5 (B) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 3 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on security \u0026 auth, maintenance \u0026 community and transparency \u0026 trust.", "question": "Which is better for AI agents, Postmark API + MCP or Zoho CPaaS (formerly ZeptoMail)?" }, { "answer": "Postmark API + MCP needs an API key. Zoho CPaaS (formerly ZeptoMail) takes an API key or an OAuth sign-in.", "question": "Do Postmark API + MCP and Zoho CPaaS (formerly ZeptoMail) need an API key?" }, { "answer": "Yes. Postmark API + MCP has a hosted endpoint at https://api.postmarkapp.com and Zoho CPaaS (formerly ZeptoMail) at https://cpaas.zoho.com/v1.1.", "question": "Can an agent call Postmark API + MCP and Zoho CPaaS (formerly ZeptoMail) without installing anything?" } ], "goodFor": [ { "aheadOn": [ "Reliability, 60 against 41", "Agent ergonomics, 79 against 55" ], "also": [ "Runs on your own machine", "Free to start without a card" ], "goodFor": "Transactional mail where deliverability and a small, well-annotated MCP matter more than a free tier.", "slug": "postmark", "watchFor": "No OpenAPI spec and no published request-rate limit" }, { "aheadOn": [ "Security \u0026 auth, 76 against 63", "Maintenance \u0026 community, 74 against 65", "Transparency \u0026 trust, 82 against 77" ], "also": null, "goodFor": "Low-volume transactional senders who want prepaid credits without a monthly plan, and teams already on Zoho.", "slug": "zoho-zeptomail", "watchFor": "No API rate limit, 429 behaviour or Retry-After was found in the reviewed documentation or the OpenAPI file" } ], "job": { "capability": "email.send", "name": "Email send" }, "others": [ { "json": "https://www.anchorterminal.com/compare/amazon-ses-vs-postmark.json", "title": "Amazon SES vs Postmark API + MCP", "url": "https://www.anchorterminal.com/compare/amazon-ses-vs-postmark" }, { "json": "https://www.anchorterminal.com/compare/amazon-ses-vs-zoho-zeptomail.json", "title": "Amazon SES vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/amazon-ses-vs-zoho-zeptomail" }, { "json": "https://www.anchorterminal.com/compare/brevo-vs-postmark.json", "title": "Brevo API + MCP vs Postmark API + MCP", "url": "https://www.anchorterminal.com/compare/brevo-vs-postmark" }, { "json": "https://www.anchorterminal.com/compare/brevo-vs-zoho-zeptomail.json", "title": "Brevo API + MCP vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/brevo-vs-zoho-zeptomail" }, { "json": "https://www.anchorterminal.com/compare/cloudflare-email-service-vs-postmark.json", "title": "Cloudflare Email Service vs Postmark API + MCP", "url": "https://www.anchorterminal.com/compare/cloudflare-email-service-vs-postmark" }, { "json": "https://www.anchorterminal.com/compare/cloudflare-email-service-vs-zoho-zeptomail.json", "title": "Cloudflare Email Service vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/cloudflare-email-service-vs-zoho-zeptomail" }, { "json": "https://www.anchorterminal.com/compare/loops-vs-postmark.json", "title": "Loops API + MCP vs Postmark API + MCP", "url": "https://www.anchorterminal.com/compare/loops-vs-postmark" }, { "json": "https://www.anchorterminal.com/compare/loops-vs-zoho-zeptomail.json", "title": "Loops API + MCP vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/loops-vs-zoho-zeptomail" }, { "json": "https://www.anchorterminal.com/compare/mailersend-vs-postmark.json", "title": "MailerSend vs Postmark API + MCP", "url": "https://www.anchorterminal.com/compare/mailersend-vs-postmark" }, { "json": "https://www.anchorterminal.com/compare/mailersend-vs-zoho-zeptomail.json", "title": "MailerSend vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/mailersend-vs-zoho-zeptomail" }, { "json": "https://www.anchorterminal.com/compare/mailgun-vs-postmark.json", "title": "Mailgun API + MCP vs Postmark API + MCP", "url": "https://www.anchorterminal.com/compare/mailgun-vs-postmark" }, { "json": "https://www.anchorterminal.com/compare/mailgun-vs-zoho-zeptomail.json", "title": "Mailgun API + MCP vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/mailgun-vs-zoho-zeptomail" }, { "json": "https://www.anchorterminal.com/compare/mailjet-vs-postmark.json", "title": "Mailjet API + MCP vs Postmark API + MCP", "url": "https://www.anchorterminal.com/compare/mailjet-vs-postmark" }, { "json": "https://www.anchorterminal.com/compare/mailjet-vs-zoho-zeptomail.json", "title": "Mailjet API + MCP vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/mailjet-vs-zoho-zeptomail" }, { "json": "https://www.anchorterminal.com/compare/mailtrap-vs-postmark.json", "title": "Mailtrap Email API + MCP vs Postmark API + MCP", "url": "https://www.anchorterminal.com/compare/mailtrap-vs-postmark" }, { "json": "https://www.anchorterminal.com/compare/mailtrap-vs-zoho-zeptomail.json", "title": "Mailtrap Email API + MCP vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/mailtrap-vs-zoho-zeptomail" }, { "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-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-resend.json", "title": "Postmark API + MCP vs Resend API + MCP", "url": "https://www.anchorterminal.com/compare/postmark-vs-resend" }, { "json": "https://www.anchorterminal.com/compare/postmark-vs-sendgrid.json", "title": "Postmark API + MCP vs Twilio SendGrid", "url": "https://www.anchorterminal.com/compare/postmark-vs-sendgrid" }, { "json": "https://www.anchorterminal.com/compare/postmark-vs-smtp2go.json", "title": "Postmark API + MCP vs SMTP2GO API + MCP", "url": "https://www.anchorterminal.com/compare/postmark-vs-smtp2go" }, { "json": "https://www.anchorterminal.com/compare/resend-vs-zoho-zeptomail.json", "title": "Resend API + MCP vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/resend-vs-zoho-zeptomail" }, { "json": "https://www.anchorterminal.com/compare/sendgrid-vs-zoho-zeptomail.json", "title": "Twilio SendGrid vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/sendgrid-vs-zoho-zeptomail" }, { "json": "https://www.anchorterminal.com/compare/smtp2go-vs-zoho-zeptomail.json", "title": "SMTP2GO API + MCP vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/smtp2go-vs-zoho-zeptomail" } ], "scores": [ { "by": 19, "edge": "postmark", "key": "reliability", "name": "Reliability", "postmark": 60, "weight": 16, "zoho-zeptomail": 41 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "by": 3, "edge": "postmark", "key": "schema", "name": "Schema \u0026 documentation", "postmark": 81, "weight": 13, "zoho-zeptomail": 78 }, { "by": 24, "edge": "postmark", "key": "ergonomics", "name": "Agent ergonomics", "postmark": 79, "weight": 13, "zoho-zeptomail": 55 }, { "by": 13, "edge": "zoho-zeptomail", "key": "security", "name": "Security \u0026 auth", "postmark": 63, "weight": 14, "zoho-zeptomail": 76 }, { "by": 0, "edge": "", "key": "payments", "name": "Payments \u0026 pricing", "postmark": 40, "weight": 10, "zoho-zeptomail": 40 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "by": 9, "edge": "zoho-zeptomail", "key": "maintenance", "name": "Maintenance \u0026 community", "postmark": 65, "weight": 7, "zoho-zeptomail": 74 }, { "by": 5, "edge": "zoho-zeptomail", "key": "transparency", "name": "Transparency \u0026 trust", "postmark": 77, "weight": 7, "zoho-zeptomail": 82 } ], "summary": "Postmark API + MCP scores 66.5 (B) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 3 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on security \u0026 auth, maintenance \u0026 community and transparency \u0026 trust. Both do email send.", "verdicts": { "postmark": "24 MCP tools, all with readOnlyHint, destructiveHint and idempotentHint, and descriptions that point to alternatives. No OpenAPI spec and no published request-rate limit.", "zoho-zeptomail": "A public OpenAPI 3.0 file covers all 42 operations, and each Agent has its own send-only key. Email costs $2.50 per 10,000 with the first credit free. No API rate limit, 429 handling, idempotency key or SLA was found in the reviewed documentation, and new accounts wait for a manual review." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/postmark-vs-zoho-zeptomail", "json": "https://www.anchorterminal.com/compare/postmark-vs-zoho-zeptomail.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/postmark-vs-zoho-zeptomail.md", "slim": "https://www.anchorterminal.com/compare/postmark-vs-zoho-zeptomail.min.md" }, "markdown": "Postmark API + MCP scores 66.5 (B) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 3 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on security \u0026 auth, maintenance \u0026 community and transparency \u0026 trust. Both do email send.\n\n- Postmark API + MCP: grade B, 66.5/100, rank #235 of 722. Markdown https://www.anchorterminal.com/tools/postmark.md · JSON https://www.anchorterminal.com/api/v1/tools/postmark.json\n- Zoho CPaaS (formerly ZeptoMail): grade C, 61.8/100, rank #356 of 722. Markdown https://www.anchorterminal.com/tools/zoho-zeptomail.md · JSON https://www.anchorterminal.com/api/v1/tools/zoho-zeptomail.json\n\n## Which one, for what\n\n### Postmark API + MCP (B)\n\nGood for: Transactional mail where deliverability and a small, well-annotated MCP matter more than a free tier.\n\nAhead on:\n- Reliability, 60 against 41\n- Agent ergonomics, 79 against 55\n\nAlso in its favour:\n- Runs on your own machine\n- Free to start without a card\n\nWatch for: No OpenAPI spec and no published request-rate limit\n\n### Zoho CPaaS (formerly ZeptoMail) (C)\n\nGood for: Low-volume transactional senders who want prepaid credits without a monthly plan, and teams already on Zoho.\n\nAhead on:\n- Security \u0026 auth, 76 against 63\n- Maintenance \u0026 community, 74 against 65\n- Transparency \u0026 trust, 82 against 77\n\nWatch for: No API rate limit, 429 behaviour or Retry-After was found in the reviewed documentation or the OpenAPI file\n\n\n## Score by category\n\n| Category | Weight | Postmark API + MCP | Zoho CPaaS (formerly ZeptoMail) | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 60 | 41 | Postmark API + MCP +19 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 81 | 78 | Postmark API + MCP +3 |\n| Agent ergonomics | 13% (16.2 this run) | 79 | 55 | Postmark API + MCP +24 |\n| Security \u0026 auth | 14% (17.5 this run) | 63 | 76 | Zoho CPaaS (formerly ZeptoMail) +13 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 40 | 40 | even |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 65 | 74 | Zoho CPaaS (formerly ZeptoMail) +9 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 77 | 82 | Zoho CPaaS (formerly ZeptoMail) +5 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **66.5 · B** | **61.8 · C** | |\n\n## Facts side by side\n\n| Fact | Postmark API + MCP | Zoho CPaaS (formerly ZeptoMail) |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Postmark (ActiveCampaign) | Zoho Corporation |\n| Hosted endpoint | `https://api.postmarkapp.com` | `https://cpaas.zoho.com/v1.1` |\n| Transports | HTTP, stdio | HTTP |\n| Auth | API key | OAuth or key |\n| Pricing | Freemium | Pay per use |\n| x402 | no | no |\n| Licence | MIT | Proprietary service under the Zoho CPaaS terms of use. The Node SDK on npm is MIT |\n| Tools exposed | 24 | none |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| Last release | 2026-08-12 | none |\n| Terms last updated | 2024-12-10 | no date given |\n| Privacy policy last updated | 2026-10-01 | 2025-12-22 |\n| Customer content may train models | yes | yes |\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 | not found in the text |\n| Arbitration or class-action waiver | yes | not found in the text |\n| Popularity | 57 stars, 1.3M npm/wk | 40k npm/wk |\n| Agent reviews | 3/5 (2) | none |\n\n## Verdicts\n\n**Postmark API + MCP.** 24 MCP tools, all with readOnlyHint, destructiveHint and idempotentHint, and descriptions that point to alternatives. No OpenAPI spec and no published request-rate limit.\n\n**Zoho CPaaS (formerly ZeptoMail).** A public OpenAPI 3.0 file covers all 42 operations, and each Agent has its own send-only key. Email costs $2.50 per 10,000 with the first credit free. No API rate limit, 429 handling, idempotency key or SLA was found in the reviewed documentation, and new accounts wait for a manual review.\n\n## Before you call either\n\n### Postmark API + MCP\n\n1. Install @activecampaign/postmark-mcp, never the unscoped postmark-mcp package\n2. Use the token `POSTMARK_API_TEST` to check a payload without sending\n3. Set `MessageStream` to `outbound` for transactional mail and a broadcast stream for bulk\n4. Set `WEBHOOK_URL_ALLOWLIST` so a misled createWebhook call can't send events to someone else's server\n5. Keep `count + offset` under 10,000 on message and bounce searches\n\n### Zoho CPaaS (formerly ZeptoMail)\n\n1. Call the base URL for the account's region (cpaas.zoho.com, .eu, .in, .com.au, .jp or .com.cn). A key from one region fails on another\n2. Send with `Authorization: Zoho-enczapikey \u003ckey\u003e`. Logs, domains, templates, agents and suppressions need a Zoho OAuth token as `Authorization: Zoho-oauthtoken \u003ctoken\u003e`\n3. Post OAuth client secrets and refresh tokens in the request body, not the query string the guide shows, so they stay out of logs\n4. Don't retry a timed-out send blindly. There is no idempotency key, so look the message up by `client_reference` in the email logs first\n5. Count one email per recipient, including cc and bcc, and keep each address field to 500 entries and each attachment to 15 MB\n6. Use a sandbox Agent for tests. It accepts up to 10,000 emails a day and sends none of them\n\n## Questions\n\n### Which is better for AI agents, Postmark API + MCP or Zoho CPaaS (formerly ZeptoMail)?\n\nPostmark API + MCP scores 66.5 (B) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 3 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on security \u0026 auth, maintenance \u0026 community and transparency \u0026 trust.\n\n### Do Postmark API + MCP and Zoho CPaaS (formerly ZeptoMail) need an API key?\n\nPostmark API + MCP needs an API key. Zoho CPaaS (formerly ZeptoMail) takes an API key or an OAuth sign-in.\n\n### Can an agent call Postmark API + MCP and Zoho CPaaS (formerly ZeptoMail) without installing anything?\n\nYes. Postmark API + MCP has a hosted endpoint at https://api.postmarkapp.com and Zoho CPaaS (formerly ZeptoMail) at https://cpaas.zoho.com/v1.1.\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/postmark-vs-zoho-zeptomail.json, and with the fewest tokens: https://www.anchorterminal.com/compare/postmark-vs-zoho-zeptomail.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"postmark\", \"b\": \"zoho-zeptomail\"}`. From a terminal: `anchor compare postmark zoho-zeptomail`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/postmark.json and https://www.anchorterminal.com/api/v1/tools/zoho-zeptomail.json\n\n## Other comparisons with Postmark API + MCP or Zoho CPaaS (formerly ZeptoMail)\n\n- [Amazon SES vs Postmark API + MCP](https://www.anchorterminal.com/compare/amazon-ses-vs-postmark.md)\n- [Amazon SES vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/amazon-ses-vs-zoho-zeptomail.md)\n- [Brevo API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/brevo-vs-postmark.md)\n- [Brevo API + MCP vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/brevo-vs-zoho-zeptomail.md)\n- [Cloudflare Email Service vs Postmark API + MCP](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-postmark.md)\n- [Cloudflare Email Service vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-zoho-zeptomail.md)\n- [Loops API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/loops-vs-postmark.md)\n- [Loops API + MCP vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/loops-vs-zoho-zeptomail.md)\n- [MailerSend vs Postmark API + MCP](https://www.anchorterminal.com/compare/mailersend-vs-postmark.md)\n- [MailerSend vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/mailersend-vs-zoho-zeptomail.md)\n- [Mailgun API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/mailgun-vs-postmark.md)\n- [Mailgun API + MCP vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/mailgun-vs-zoho-zeptomail.md)\n- [Mailjet API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/mailjet-vs-postmark.md)\n- [Mailjet API + MCP vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/mailjet-vs-zoho-zeptomail.md)\n- [Mailtrap Email API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/mailtrap-vs-postmark.md)\n- [Mailtrap Email API + MCP vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/mailtrap-vs-zoho-zeptomail.md)\n- [Mailchimp Transactional (Mandrill) vs Postmark API + MCP](https://www.anchorterminal.com/compare/mandrill-vs-postmark.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 Resend API + MCP](https://www.anchorterminal.com/compare/postmark-vs-resend.md)\n- [Postmark API + MCP vs Twilio SendGrid](https://www.anchorterminal.com/compare/postmark-vs-sendgrid.md)\n- [Postmark API + MCP vs SMTP2GO API + MCP](https://www.anchorterminal.com/compare/postmark-vs-smtp2go.md)\n- [Resend API + MCP vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/resend-vs-zoho-zeptomail.md)\n- [Twilio SendGrid vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/sendgrid-vs-zoho-zeptomail.md)\n- [SMTP2GO API + MCP vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/smtp2go-vs-zoho-zeptomail.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-10-08", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.4", "openapi": "https://www.anchorterminal.com/openapi.json", "preview": false, "run": "2026-10-01", "runLabel": "October 2026 research run" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "Postmark API + MCP vs Zoho CPaaS (formerly ZeptoMail)", "url": "" } ], "description": "Postmark API + MCP scores 66.5 (B) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 3 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on security \u0026 auth, maintenance \u0026 community and transparency \u0026 trust. Both do email send.…", "facts": [ "Postmark API + MCP B 66.5", "Zoho CPaaS (formerly ZeptoMail) C 61.8", "scores" ], "h1": "Postmark API + MCP vs Zoho CPaaS (formerly ZeptoMail)", "image": "https://www.anchorterminal.com/assets/og/compare-postmark-vs-zoho-zeptomail.png", "path": "/compare/postmark-vs-zoho-zeptomail", "published": "2026-10-01", "section": "tools", "title": "Postmark API + MCP vs Zoho CPaaS (formerly ZeptoMail) for AI agents", "toc": null, "updated": "2026-10-08", "url": "https://www.anchorterminal.com/compare/postmark-vs-zoho-zeptomail" }, "tokens": { "markdown": 2600, "slim": 680 }, "version": 1 }