# Mailtrap Email API + MCP (slim)

> Email platform from Railsware Products Studio LLC for transactional and bulk sending, inbound mail, templates, contacts and sandbox testing. Agents reach it through a REST API, SMTP, SDKs, a CLI and a local MCP server.

- Full: https://www.anchorterminal.com/tools/mailtrap.md (~7,850 tokens) · this version ~1,880 tokens · JSON https://www.anchorterminal.com/tools/mailtrap.json · canonical https://www.anchorterminal.com/tools/mailtrap
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-08

**B · 66.8/100 · rank #228 of 722 · #5 in Email delivery APIs · not agent-ready · confidence medium**


Assessment: Public OpenAPI 3.1 specs, API tokens with per-resource permissions and expiry dates, and a free plan of 4,000 emails a month without a card support agent use. The MCP server loads 125 tools with no toolsets, no idempotency key was found for sends, and the status page records a sending outage of 1 hour 32 minutes on 1 August 2026.

## Facts

- Kind: HTTP API · vendor: Mailtrap (Railsware) · category: Email delivery APIs · legal entity: Railsware Products Studio LLC · provenance 87/100
- Endpoint: `https://send.api.mailtrap.io` (HTTP, stdio)
- Auth: API key · pricing: Freemium · x402: no · licence: Proprietary service under Mailtrap's terms of service. The MCP server, the Node.js SDK and the CLI are MIT
- Probe metrics: not measured yet (probes haven't run)
- Free tier: 4,000 emails a month, 150 a day, 1 user, 1 domain, 3-day email logs. No overage on the free plan
- Rate limits: 150 requests per 10 seconds per API token. Contacts API 200 per 60 seconds per account, Stats and Suppressions 10 per 60 seconds per account. 429 with `x-ratelimit-limit`, `x-ratelimit-remaining` and `x-ratelimit-reset` per the OpenAPI specs
- Sending limits: 150 emails an hour for new accounts, raised on paid plans. Batch calls take up to 500 emails. Messages up to 10 MB, or 30 MB on Business and above by request. 10 concurrent SMTP connections per account
- Before first send: Create an account, verify a sending domain (SPF, DKIM, DMARC) and create an API token in the UI
- Endpoints: Transactional at https://send.api.mailtrap.io/api/send, bulk at https://bulk.api.mailtrap.io/api/send, batch at /api/batch on each host. Sandbox sending uses a different base URL
- Inbound: Inbound Email inboxes created through the API, on a Mailtrap address or a custom domain, read by polling or by webhook signed with HMAC-SHA256. The docs say the UI is coming soon
- Transactional vs marketing: Separate transactional and bulk streams on separate hosts, plus an Email Marketing product billed by contacts
- Sandbox: Email Sandbox captures test mail without delivery. Free plan 50 test emails a month, paid plans from $17 a month
- Data retention: Email logs kept 3 days on Free, 5 on Basic, 15 on Business and 30 on Enterprise. Data hosted in the US on AWS us-east-1 and Google
- MCP server: Official, local stdio via npx mcp-mailtrap (0.9.0, MIT), 125 tools, 53 marked read-only, no hosted version found
- SDKs and CLI: Node.js, Python, PHP, Ruby, Java, .NET, Go and Elixir. Mailtrap CLI v0.8.0 through Homebrew or go install
- OpenAPI: Ten OpenAPI 3.1 specs at version 2.0.0 in mailtrap/mailtrap-openapi, covering sending, sandbox, inbound, templates, contacts, campaigns and account management
- Certifications: ISO/IEC 27001:2022 and a SOC 2 Type II report for 1 September to 30 November 2025, released under NDA through the trust centre
- Prices: Basic 10k $15 per month (plan); Basic 100k $30 per month (plan); Business 100k $85 per month (plan); Enterprise 1.5M $750 per month (plan); Overage on Basic $1 per 1,000 emails; Overage on Business $0.88 per 1,000 emails; Overage on Enterprise $0.55 per 1,000 emails

- Scores: Reliability 65, Performance pending, Schema & documentation 82, Agent ergonomics 62, Security & auth 60, Payments & pricing 40, Task success pending, Maintenance & community 93, Transparency & trust 77 · total over the 7 assessed categories
- Why: Reliability, Graded as a hosted service. · Schema & documentation, Graded on the REST API and the MCP server. · Agent ergonomics, 125 MCP tools registered at once, with no toolsets, filtering or dynamic loading (5). · Security & auth, API tokens with permissions per resource, an expiry date (365 days by default), a reset with a 12-hour overlap and management through the AP… · Payments & pricing, No x402, MPP or L402 (0). · Maintenance & community, mailtrap-nodejs v5.0.0, the Python SDK 2.11.0 and CLI v0.8.0 were all released on 8 October 2026 (30). · Transparency & trust, Closed service with published terms, and MIT licences on the MCP server, Node SDK and CLI (20).
- Sources: 26, open questions: 7, both in the full twin
- Capabilities: email.send, email.inbound, email.templates, email.domains, email.analytics, email.marketing, email.inbox, email.threads
- JSON: https://www.anchorterminal.com/api/v1/tools/mailtrap.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/mailtrap.svg` or a link to https://www.anchorterminal.com/tools/mailtrap from a page on mailtrap.io or one of its subdomains, or the README of github.com/mailtrap/mailtrap-mcp, then `POST https://www.anchorterminal.com/api/v1/verify` `{"slug", "url"}` or `verify_listing` at /mcp; re-checked weekly, no effect on the grade. Snippets in the full twin.

## Before you call it

1. Ask the operator to create the first API token at mailtrap.io/settings/api-tokens. The first token can't be created through the API.
2. Send transactional mail to send.api.mailtrap.io and bulk mail to bulk.api.mailtrap.io. Sandbox sending uses a different base URL and an inbox ID.
3. Verify a sending domain before the first production send, and use Email Sandbox to test payloads without delivery.
4. Stay under 150 requests per 10 seconds per token, and 10 per 60 seconds per account on the Stats and Suppressions APIs. On 429, back off until `x-ratelimit-reset`.
5. Don't retry a timed-out send blindly, because no idempotency key was found. Check the email logs first.

## Connect

```bash
npm install mailtrap
```

```bash
curl -X POST https://send.api.mailtrap.io/api/send \
  -H 'Authorization: Bearer YOUR_API_KEY' \
  -H 'Content-Type: application/json' \
  -d '{
    "from": {"email": "sender@example.com"},
    "to": [{"email": "recipient@example.com"}],
    "subject": "Hello from Mailtrap",
    "text": "Welcome to Mailtrap!"
  }'
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/mailtrap

## Similar tools

| Tool | Grade | Score | Shared capabilities | Slim |
| --- | --- | --- | --- | --- |
| Resend API + MCP | BB | 75.1 | email.send, email.inbound, email.templates, email.domains, email.analytics, email.marketing | https://www.anchorterminal.com/tools/resend.min.md |
| AgentMail API + MCP | BB | 74.9 | email.inbox, email.send, email.inbound, email.threads, email.domains, email.analytics | https://www.anchorterminal.com/tools/agentmail.min.md |
| MailerSend | B | 69.5 | email.send, email.inbound, email.templates, email.domains, email.analytics, email.threads | https://www.anchorterminal.com/tools/mailersend.min.md |
| Postmark API + MCP | B | 66.5 | email.send, email.inbound, email.templates, email.domains, email.analytics, email.marketing | https://www.anchorterminal.com/tools/postmark.min.md |
| Twilio SendGrid | B | 63.6 | email.send, email.inbound, email.templates, email.domains, email.analytics, email.marketing | https://www.anchorterminal.com/tools/sendgrid.min.md |


## Panel reviews (0, desk reviews from public material, no calls made)