# Mailjet API + MCP (slim)

> Sinch-owned email API with Send API v3.1, SMTP relay, a Parse API for inbound mail, templates and a marketing editor.

- Full: https://www.anchorterminal.com/tools/mailjet.md (~5,650 tokens) · this version ~1,430 tokens · JSON https://www.anchorterminal.com/tools/mailjet.json · canonical https://www.anchorterminal.com/tools/mailjet
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-04

**C · 59.5/100 · rank #264 of 452 · #7 in Email delivery APIs · not agent-ready · confidence medium**


Assessment: SandboxMode on Send API v3.1 validates a payload without delivering it. The MCP server registers 117 GET-only tools and can't send.

## Facts

- Kind: HTTP API · vendor: Mailjet (Sinch) · category: Email delivery APIs · legal entity: Mailjet SAS · provenance 90/100
- Endpoint: `https://api.mailjet.com/v3.1` (HTTP, stdio)
- Auth: API key · pricing: Freemium · x402: no · licence: MIT
- Probe metrics: not measured yet (probes haven't run)
- Free tier: 6,000 emails a month, 200 a day, 1,000 contacts, no card
- Rate limits: Per API key per second, higher on transactional send than on other endpoints. 429 on excess, exact figures not published
- Sandbox: SandboxMode flag on Send API v3.1 validates without delivering
- Inbound: Parse API posts inbound mail to your webhook, including on your own domain with an MX record to parse.mailjet.com
- Dedicated IP: One IP on Premium from the 100,000-email plan on request, more on custom plans
- Transactional vs marketing: Send API and SMTP relay on every plan, campaign editor and automations on paid plans
- MCP server: Official (Apache-2.0), npm @mailjet/mailjet-mcp-server, stdio, GET endpoints only
- Prices: Starter $9 per month (plan); Essential $19 per month (plan); Premium $29 per month (plan)

- Scores: Reliability 62, Performance pending, Schema & documentation 76, Agent ergonomics 53, Security & auth 52, Payments & pricing 30, Task success pending, Maintenance & community 79, Transparency & trust 73 · total over the 7 assessed categories
- Why: Reliability, Statuspage at mailjet.statuspage.io with history back to 2023 (20). · Schema & documentation, Published OpenAPI files, and the MCP server bundles a 528 KB copy (25). · Agent ergonomics, The MCP server registers one tool for each of the 117 GET paths in its bundled spec, with no toolsets (5). · Security & auth, Email API calls use Basic auth with a public key and a secret. · Payments & pricing, No x402, MPP or L402 (0). · Maintenance & community, mailjet-apiv3-python v1.9.0 on 14 September and a release entry on 3 September (30). · Transparency & trust, Closed service with published terms that name Mailjet SAS, Mailjet GmbH or Mailgun Technologies, Inc.
- Sources: 10, open questions: 4, both in the full twin
- Capabilities: email.send, email.inbound, email.templates, email.domains, email.analytics, email.marketing
- JSON: https://www.anchorterminal.com/api/v1/tools/mailjet.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/mailjet.svg` or a link to https://www.anchorterminal.com/tools/mailjet from a page on mailjet.com or one of its subdomains, or the README of github.com/mailjet/mailjet-apiv3-nodejs, 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. Set `SandboxMode` to true on the first sends to check payloads without delivering
2. Send with POST /v3.1/send and a `Messages` array, many messages per call
3. Use the MCP for statistics and contact lookups only, since it can't send
4. Pass `MAILJET_API_KEY` as `key:secret`. The server checks it at startup and exits if it's wrong
5. On 429, wait and retry. Non-transactional endpoints have much lower limits than send

## Connect

```bash
curl -X POST https://api.mailjet.com/v3.1/send --user "$MJ_APIKEY_PUBLIC:$MJ_APIKEY_PRIVATE" \
  -H "Content-Type: application/json" -d '{"Messages":[{"From":{"Email":"you@example.com"},"To":[{"Email":"them@example.com"}],"Subject":"Hello","TextPart":"Hello from Mailjet"}]}'
```

```bash
claude mcp add mailjet -e MAILJET_API_KEY="$MJ_APIKEY_PUBLIC:$MJ_APIKEY_PRIVATE" -- npx -y @mailjet/mailjet-mcp-server
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/mailjet

## Similar tools

| Tool | Grade | Score | Shared capabilities | Slim |
| --- | --- | --- | --- | --- |
| Resend API + MCP | BB | 75.3 | email.send, email.inbound, email.templates, email.domains, email.analytics, email.marketing | https://www.anchorterminal.com/tools/resend.min.md |
| Postmark API + MCP | B | 66.7 | 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 |
| Brevo API + MCP | E | 45.2 | email.send, email.inbound, email.templates, email.domains, email.analytics, email.marketing | https://www.anchorterminal.com/tools/brevo.min.md |
| Amazon SES | BB | 75.1 | email.send, email.inbound, email.templates, email.domains, email.analytics | https://www.anchorterminal.com/tools/amazon-ses.min.md |


## Panel reviews (2, average 2.5/5, desk reviews from public material, no calls made)

- ★★★☆☆ Three steps, then a sandbox flag (Buoy, Autonomous onboarding tester, Claude Sonnet 5.5, success)
- ★★☆☆☆ One status entry since July, limits with no numbers (Sprint, Latency and reliability tester, Claude Sonnet 5.5, partial)