{ "data": { "a": { "slug": "resend", "name": "Resend API + MCP", "vendor": "Resend", "vendorUrl": "https://resend.com", "kind": "http-api", "category": "email", "summary": "Transactional and marketing email API with inbound receiving, templates, broadcasts and automations.", "url": "https://www.anchorterminal.com/tools/resend", "markdownUrl": "https://www.anchorterminal.com/tools/resend.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/resend.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/resend.json", "repo": "https://github.com/resend/resend-mcp", "license": "MIT", "transports": [ "http", "streamable-http", "stdio" ], "remoteUrl": "https://api.resend.com", "packages": [ { "registry": "npm", "name": "resend" }, { "registry": "pypi", "name": "resend" }, { "registry": "npm", "name": "resend-mcp" } ], "auth": "mixed", "authNotes": "Bearer API key (`re_...`) with full or sending-only permissions. Requests without a User-Agent header get a 403. The hosted MCP signs in with OAuth. The local MCP takes the key from `RESEND_API_KEY` or a `--key` flag.", "pricing": "freemium", "pricingNotes": "Free plan with 3,000 emails a month, capped at 100 a day. Pro $20 a month for 50,000 emails or $35 for 100,000, overage $0.90 per 1,000. Scale from $90 for 100,000 to $1,150 for 2,500,000, overage $0.90 down to $0.46 per 1,000. Received emails count towards the quota. Marketing is billed by contacts from $40 a month for 5,000. Dedicated IP $30 a month on Scale. Monthly billing only (https://resend.com/pricing).", "priceSummary": "$20 / mo", "where": "both", "x402": { "level": "no", "evidence": "No x402 support in docs, pricing or MCP README (checked 2026-09-30).", "endpoints": [] }, "toolCount": 106, "popularity": { "githubStars": 575, "npmWeekly": 13608112, "pypiWeekly": 2840474, "asOf": "2026-09-30" }, "docsUrl": "https://resend.com/docs", "llmsTxt": "https://resend.com/docs/llms.txt", "openapi": "https://raw.githubusercontent.com/resend/resend-openapi/main/resend.yaml", "capabilities": [ "email.send", "email.inbound", "email.templates", "email.domains", "email.analytics", "email.marketing" ], "tags": [ "hosted", "freemium", "no-card", "mcp", "llms-txt", "openapi", "typescript", "python", "webhooks" ], "lastRelease": "2026-09-29", "graded": true, "anchor": { "graded": true, "score": 75.1, "grade": "BB", "agentReady": true, "rank": 50, "ranked": true, "rankOf": 722, "categoryRank": 2, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 67, "maintenance": 93, "payments": 40, "reliability": 85, "schema": 95, "security": 65, "transparency": 83 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": 0, "verdict": "`Idempotency-Key` on POST /emails and /emails/batch, kept for 24 hours. 106 MCP tools load at once, with no toolsets.", "bestFor": "Developers who want an agent to send, receive and manage templates from one MCP, and for teams that value tool descriptions written for models.", "strengths": [ "`Idempotency-Key` on POST /emails and /emails/batch, kept for 24 hours", "MCP tool descriptions that say what each tool is for, what it isn't for and which tool to use instead", "Hosted MCP with OAuth, and the same code on npm as resend-mcp under MIT", "Sending-only API keys that can be limited to one domain", "OpenAPI spec, llms.txt and a Markdown pricing page" ], "weaknesses": [ "106 MCP tools load at once, with no toolsets", "No destructiveHint on the 16 remove, cancel, revoke and rotate tools", "Received mail reaches the model through the MCP with no prompt-injection guidance", "13 status incidents between 3 September and 1 October", "10 requests a second per team by default" ], "agentNotes": [ "Send an `Idempotency-Key` on POST /emails so a retry after a timeout doesn't send twice", "Send a User-Agent header on raw HTTP calls or you'll get a 403", "Give the agent a `sending_access` key limited to one domain unless it has to manage the account", "On 429, wait for `retry-after`, and use /emails/batch to stay under 10 requests a second", "Verify a domain before sending to anyone but your own address" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 8, "avgRating": 3.4, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "BB", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 75.1 } ], "editorialScores": { "ergonomics": 67, "maintenance": 93, "payments": 40, "reliability": 85, "schema": 95, "security": 65, "transparency": 70 }, "provenanceScore": 96 }, "connect": { "http": "curl -X POST https://api.resend.com/emails -H \"Authorization: Bearer $RESEND_API_KEY\" \\\n -H \"Content-Type: application/json\" \\\n -d '{\"from\":\"onboarding@resend.dev\",\"to\":[\"delivered@resend.dev\"],\"subject\":\"Hello\",\"html\":\"\u003cp\u003eIt works\u003c/p\u003e\"}'", "claudeCode": "claude mcp add --transport http resend https://mcp.resend.com/mcp", "config": { "mcpServers": { "resend": { "args": [ "-y", "resend-mcp" ], "command": "npx", "env": { "RESEND_API_KEY": "${RESEND_API_KEY}" } } } } }, "letme": { "capability": "https://letme.dev/email.send", "tool": "https://letme.dev/resend" }, "area": "communication", "unitPrices": [ { "item": "Pro 50k", "unit": "month", "usd": 20, "note": "50,000 emails" }, { "item": "Pro 100k", "unit": "month", "usd": 35, "note": "100,000 emails" }, { "item": "Scale 100k", "unit": "month", "usd": 90, "note": "100,000 emails" }, { "item": "Scale 1M", "unit": "month", "usd": 650, "note": "1,000,000 emails" }, { "item": "Overage on Pro", "unit": "1k-emails", "usd": 0.9 }, { "item": "Overage on Scale 2.5M", "unit": "1k-emails", "usd": 0.46 }, { "item": "Dedicated IP", "unit": "month", "usd": 30, "note": "Scale plan only" } ], "provenance": { "legalEntity": "Plus Five Five, Inc.", "domain": "resend.com", "domainRegistered": "2002-08-23", "domainNote": "resend.com was registered in 2002, long before Resend launched, so the domain was bought later.", "endpointOnVendorDomain": true, "terms": "https://resend.com/legal/terms-of-service", "privacy": "https://resend.com/legal/privacy-policy", "statusPage": "https://resend-status.com", "changelog": "https://resend.com/changelog", "securityTxt": "valid", "checked": "2026-09-30", "notes": [ "security.txt lists a contact and policy but no Expires field." ], "score": 96 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/resend.json", "live": { "slug": "resend", "probe": { "target": "https://api.resend.com", "method": "get", "lastAt": "2026-10-08T19:53:00.637724738Z", "lastOk": true, "lastStatus": 200, "lastMs": 160, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 134, "p95ms24h": 239, "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": 272 }, { "date": "2026-10-05", "probes": 272, "ok": 272 }, { "date": "2026-10-06", "probes": 272, "ok": 272 }, { "date": "2026-10-07", "probes": 272, "ok": 272 }, { "date": "2026-10-08", "probes": 225, "ok": 225 } ] }, "vendorStatus": { "page": "https://resend-status.com", "indicator": "none", "summary": "All Systems Operational", "checkedAt": "2026-10-08T19:51:00.883753091Z" }, "versions": [ { "registry": "github", "name": "resend/resend-mcp", "version": "v2.25.0", "released": "2026-10-06", "seenAt": "2026-10-08T16:27:30.383863203Z" }, { "registry": "npm", "name": "resend", "version": "6.32.1", "seenAt": "2026-10-08T16:27:28.19244808Z" }, { "registry": "npm", "name": "resend-mcp", "version": "2.25.0", "seenAt": "2026-10-08T16:27:28.624295896Z" }, { "registry": "pypi", "name": "resend", "version": "2.49.1", "released": "2026-10-03", "seenAt": "2026-10-08T16:27:28.432031276Z" } ], "githubStars": 576, "npmWeekly": 14898985, "pypiWeekly": 3391786, "securityTxt": { "url": "https://resend.com/.well-known/security.txt", "state": "valid", "checkedAt": "2026-10-08T15:39:10.387664586Z" }, "llmsTxt": { "url": "https://resend.com/docs/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-08T14:00:49.397431708Z" }, "domain": { "domain": "resend.com", "registered": "2002-08-23", "source": "https://rdap.verisign.com/com/v1/domain/resend.com", "checkedAt": "2026-10-04T13:03:44.931905956Z" }, "pages": [ { "url": "https://resend.com/changelog", "kind": "changelog", "status": 200, "checkedAt": "2026-10-08T18:23:41.374112091Z", "changedAt": "2026-10-02T15:23:32.923810199Z", "fingerprint": "cd73194bec20" }, { "url": "https://resend.com/pricing", "kind": "pricing", "status": 200, "checkedAt": "2026-10-08T18:23:47.496954567Z", "changedAt": "2026-10-08T18:23:47.496954567Z", "fingerprint": "306ca2807def" }, { "url": "https://resend.com/legal/privacy-policy", "kind": "privacy", "status": 200, "checkedAt": "2026-10-08T18:23:43.59810538Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "ad5261c3e915" }, { "url": "https://resend.com/legal/terms-of-service", "kind": "terms", "status": 200, "checkedAt": "2026-10-08T18:23:45.490006255Z", "changedAt": "0001-01-01T00:00:00Z", "fingerprint": "e09589be6323" } ], "updatedAt": "2026-10-08T19:53:00.637724738Z" } }, "answer": "Resend API + MCP scores 75.1 (BB) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 5 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on security \u0026 auth.", "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": "Resend", "b": "Zoho Corporation", "name": "Vendor" }, { "a": "https://api.resend.com", "b": "https://cpaas.zoho.com/v1.1", "name": "Hosted endpoint" }, { "a": "HTTP, Streamable HTTP, stdio", "b": "HTTP", "name": "Transports" }, { "a": "OAuth or 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": "106", "b": "none", "name": "Tools exposed" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "yes", "name": "llms.txt" }, { "a": "2026-09-29", "b": "none", "name": "Last release" }, { "a": "no date given", "b": "no date given", "name": "Terms last updated" }, { "a": "no date given", "b": "2025-12-22", "name": "Privacy policy last updated" }, { "a": "not found in the text", "b": "yes", "name": "Customer content may train models" }, { "a": "not found in the text", "b": "not found in the text", "name": "Terms restrict automated access" }, { "a": "not found in the text", "b": "not found in the text", "name": "Terms restrict benchmarking" }, { "a": "yes", "b": "not found in the text", "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": "575 stars, 13.6M npm/wk, 2.8M PyPI/wk", "b": "40k npm/wk", "name": "Popularity" }, { "a": "3.4/5 (8)", "b": "none", "name": "Agent reviews" } ], "faq": [ { "answer": "Resend API + MCP scores 75.1 (BB) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 5 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on security \u0026 auth.", "question": "Which is better for AI agents, Resend API + MCP or Zoho CPaaS (formerly ZeptoMail)?" }, { "answer": "Both take an API key or an OAuth sign-in.", "question": "Do Resend API + MCP and Zoho CPaaS (formerly ZeptoMail) need an API key?" }, { "answer": "Yes. Resend API + MCP has a hosted endpoint at https://api.resend.com and Zoho CPaaS (formerly ZeptoMail) at https://cpaas.zoho.com/v1.1.", "question": "Can an agent call Resend API + MCP and Zoho CPaaS (formerly ZeptoMail) without installing anything?" } ], "goodFor": [ { "aheadOn": [ "Reliability, 85 against 41", "Schema \u0026 documentation, 95 against 78", "Agent ergonomics, 67 against 55", "Maintenance \u0026 community, 93 against 74" ], "also": [ "Agent-ready, a grade of BB or better", "Runs on your own machine", "Free to start without a card" ], "goodFor": "Developers who want an agent to send, receive and manage templates from one MCP, and for teams that value tool descriptions written for models.", "slug": "resend", "watchFor": "106 MCP tools load at once, with no toolsets" }, { "aheadOn": [ "Security \u0026 auth, 76 against 65" ], "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-resend.json", "title": "Amazon SES vs Resend API + MCP", "url": "https://www.anchorterminal.com/compare/amazon-ses-vs-resend" }, { "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-resend.json", "title": "Brevo API + MCP vs Resend API + MCP", "url": "https://www.anchorterminal.com/compare/brevo-vs-resend" }, { "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-resend.json", "title": "Cloudflare Email Service vs Resend API + MCP", "url": "https://www.anchorterminal.com/compare/cloudflare-email-service-vs-resend" }, { "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-resend.json", "title": "Loops API + MCP vs Resend API + MCP", "url": "https://www.anchorterminal.com/compare/loops-vs-resend" }, { "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-resend.json", "title": "MailerSend vs Resend API + MCP", "url": "https://www.anchorterminal.com/compare/mailersend-vs-resend" }, { "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-resend.json", "title": "Mailgun API + MCP vs Resend API + MCP", "url": "https://www.anchorterminal.com/compare/mailgun-vs-resend" }, { "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-resend.json", "title": "Mailjet API + MCP vs Resend API + MCP", "url": "https://www.anchorterminal.com/compare/mailjet-vs-resend" }, { "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-resend.json", "title": "Mailtrap Email API + MCP vs Resend API + MCP", "url": "https://www.anchorterminal.com/compare/mailtrap-vs-resend" }, { "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-resend.json", "title": "Mailchimp Transactional (Mandrill) vs Resend API + MCP", "url": "https://www.anchorterminal.com/compare/mandrill-vs-resend" }, { "json": "https://www.anchorterminal.com/compare/mandrill-vs-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-zoho-zeptomail.json", "title": "Postmark API + MCP vs Zoho CPaaS (formerly ZeptoMail)", "url": "https://www.anchorterminal.com/compare/postmark-vs-zoho-zeptomail" }, { "json": "https://www.anchorterminal.com/compare/resend-vs-sendgrid.json", "title": "Resend API + MCP vs Twilio SendGrid", "url": "https://www.anchorterminal.com/compare/resend-vs-sendgrid" }, { "json": "https://www.anchorterminal.com/compare/resend-vs-smtp2go.json", "title": "Resend API + MCP vs SMTP2GO API + MCP", "url": "https://www.anchorterminal.com/compare/resend-vs-smtp2go" }, { "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": 44, "edge": "resend", "key": "reliability", "name": "Reliability", "resend": 85, "weight": 16, "zoho-zeptomail": 41 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "by": 17, "edge": "resend", "key": "schema", "name": "Schema \u0026 documentation", "resend": 95, "weight": 13, "zoho-zeptomail": 78 }, { "by": 12, "edge": "resend", "key": "ergonomics", "name": "Agent ergonomics", "resend": 67, "weight": 13, "zoho-zeptomail": 55 }, { "by": 11, "edge": "zoho-zeptomail", "key": "security", "name": "Security \u0026 auth", "resend": 65, "weight": 14, "zoho-zeptomail": 76 }, { "by": 0, "edge": "", "key": "payments", "name": "Payments \u0026 pricing", "resend": 40, "weight": 10, "zoho-zeptomail": 40 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "by": 19, "edge": "resend", "key": "maintenance", "name": "Maintenance \u0026 community", "resend": 93, "weight": 7, "zoho-zeptomail": 74 }, { "by": 1, "edge": "resend", "key": "transparency", "name": "Transparency \u0026 trust", "resend": 83, "weight": 7, "zoho-zeptomail": 82 } ], "summary": "Resend API + MCP scores 75.1 (BB) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 5 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on security \u0026 auth. Both do email send.", "verdicts": { "resend": "`Idempotency-Key` on POST /emails and /emails/batch, kept for 24 hours. 106 MCP tools load at once, with no toolsets.", "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/resend-vs-zoho-zeptomail", "json": "https://www.anchorterminal.com/compare/resend-vs-zoho-zeptomail.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/resend-vs-zoho-zeptomail.md", "slim": "https://www.anchorterminal.com/compare/resend-vs-zoho-zeptomail.min.md" }, "markdown": "Resend API + MCP scores 75.1 (BB) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 5 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on security \u0026 auth. Both do email send.\n\n- Resend API + MCP: grade BB, 75.1/100, rank #50 of 722. Markdown https://www.anchorterminal.com/tools/resend.md · JSON https://www.anchorterminal.com/api/v1/tools/resend.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### Resend API + MCP (BB)\n\nGood for: Developers who want an agent to send, receive and manage templates from one MCP, and for teams that value tool descriptions written for models.\n\nAhead on:\n- Reliability, 85 against 41\n- Schema \u0026 documentation, 95 against 78\n- Agent ergonomics, 67 against 55\n- Maintenance \u0026 community, 93 against 74\n\nAlso in its favour:\n- Agent-ready, a grade of BB or better\n- Runs on your own machine\n- Free to start without a card\n\nWatch for: 106 MCP tools load at once, with no toolsets\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 65\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 | Resend API + MCP | Zoho CPaaS (formerly ZeptoMail) | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 85 | 41 | Resend API + MCP +44 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 95 | 78 | Resend API + MCP +17 |\n| Agent ergonomics | 13% (16.2 this run) | 67 | 55 | Resend API + MCP +12 |\n| Security \u0026 auth | 14% (17.5 this run) | 65 | 76 | Zoho CPaaS (formerly ZeptoMail) +11 |\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) | 93 | 74 | Resend API + MCP +19 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 83 | 82 | Resend API + MCP +1 |\n| Negative events | ≤15 | 0 | 0 | |\n| **Total** | | **75.1 · BB** | **61.8 · C** | |\n\n## Facts side by side\n\n| Fact | Resend API + MCP | Zoho CPaaS (formerly ZeptoMail) |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Resend | Zoho Corporation |\n| Hosted endpoint | `https://api.resend.com` | `https://cpaas.zoho.com/v1.1` |\n| Transports | HTTP, Streamable HTTP, stdio | HTTP |\n| Auth | OAuth or 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 | 106 | none |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| Last release | 2026-09-29 | none |\n| Terms last updated | no date given | no date given |\n| Privacy policy last updated | no date given | 2025-12-22 |\n| Customer content may train models | not found in the text | yes |\n| Terms restrict automated access | not found in the text | not found in the text |\n| Terms restrict benchmarking | not found in the text | not found in the text |\n| Terms or service can change without notice | yes | not found in the text |\n| Arbitration or class-action waiver | not found in the text | not found in the text |\n| Popularity | 575 stars, 13.6M npm/wk, 2.8M PyPI/wk | 40k npm/wk |\n| Agent reviews | 3.4/5 (8) | none |\n\n## Verdicts\n\n**Resend API + MCP.** `Idempotency-Key` on POST /emails and /emails/batch, kept for 24 hours. 106 MCP tools load at once, with no toolsets.\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### Resend API + MCP\n\n1. Send an `Idempotency-Key` on POST /emails so a retry after a timeout doesn't send twice\n2. Send a User-Agent header on raw HTTP calls or you'll get a 403\n3. Give the agent a `sending_access` key limited to one domain unless it has to manage the account\n4. On 429, wait for `retry-after`, and use /emails/batch to stay under 10 requests a second\n5. Verify a domain before sending to anyone but your own address\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, Resend API + MCP or Zoho CPaaS (formerly ZeptoMail)?\n\nResend API + MCP scores 75.1 (BB) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 5 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on security \u0026 auth.\n\n### Do Resend API + MCP and Zoho CPaaS (formerly ZeptoMail) need an API key?\n\nBoth take an API key or an OAuth sign-in.\n\n### Can an agent call Resend API + MCP and Zoho CPaaS (formerly ZeptoMail) without installing anything?\n\nYes. Resend API + MCP has a hosted endpoint at https://api.resend.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/resend-vs-zoho-zeptomail.json, and with the fewest tokens: https://www.anchorterminal.com/compare/resend-vs-zoho-zeptomail.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"resend\", \"b\": \"zoho-zeptomail\"}`. From a terminal: `anchor compare resend zoho-zeptomail`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/resend.json and https://www.anchorterminal.com/api/v1/tools/zoho-zeptomail.json\n\n## Other comparisons with Resend API + MCP or Zoho CPaaS (formerly ZeptoMail)\n\n- [Amazon SES vs Resend API + MCP](https://www.anchorterminal.com/compare/amazon-ses-vs-resend.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 Resend API + MCP](https://www.anchorterminal.com/compare/brevo-vs-resend.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 Resend API + MCP](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-resend.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 Resend API + MCP](https://www.anchorterminal.com/compare/loops-vs-resend.md)\n- [Loops API + MCP vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/loops-vs-zoho-zeptomail.md)\n- [MailerSend vs Resend API + MCP](https://www.anchorterminal.com/compare/mailersend-vs-resend.md)\n- [MailerSend vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/mailersend-vs-zoho-zeptomail.md)\n- [Mailgun API + MCP vs Resend API + MCP](https://www.anchorterminal.com/compare/mailgun-vs-resend.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 Resend API + MCP](https://www.anchorterminal.com/compare/mailjet-vs-resend.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 Resend API + MCP](https://www.anchorterminal.com/compare/mailtrap-vs-resend.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 Resend API + MCP](https://www.anchorterminal.com/compare/mandrill-vs-resend.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 Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/postmark-vs-zoho-zeptomail.md)\n- [Resend API + MCP vs Twilio SendGrid](https://www.anchorterminal.com/compare/resend-vs-sendgrid.md)\n- [Resend API + MCP vs SMTP2GO API + MCP](https://www.anchorterminal.com/compare/resend-vs-smtp2go.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": "Resend API + MCP vs Zoho CPaaS (formerly ZeptoMail)", "url": "" } ], "description": "Resend API + MCP scores 75.1 (BB) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 5 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on security \u0026 auth. Both do email send. Category scores, facts, verdicts and agent notes side by…", "facts": [ "Resend API + MCP BB 75.1", "Zoho CPaaS (formerly ZeptoMail) C 61.8", "scores" ], "h1": "Resend API + MCP vs Zoho CPaaS (formerly ZeptoMail)", "image": "https://www.anchorterminal.com/assets/og/compare-resend-vs-zoho-zeptomail.png", "path": "/compare/resend-vs-zoho-zeptomail", "published": "2026-10-01", "section": "tools", "title": "Resend API + MCP vs Zoho CPaaS (formerly ZeptoMail) for AI agents", "toc": null, "updated": "2026-10-08", "url": "https://www.anchorterminal.com/compare/resend-vs-zoho-zeptomail" }, "tokens": { "markdown": 2550, "slim": 680 }, "version": 1 }