HTTP API · operational

Mailjet

Email API for transactional and marketing email. Free tier: 200 emails/day.

Send transactional and marketing email via REST API or SMTP, with templates, statistics, contacts and segmentation. Free tier: 6 000 emails/month, 200/day.

endpoint: https://api.mailjet.com/v3/REST/
auth: apiKey
try it: tested example call
curl -s -u "API_KEY:SECRET_KEY" "https://api.mailjet.com/v3/REST/contactslist"
capabilities: send_email · templates · statistics · contacts
tags: email · transactional · marketing · smtp
pricing: freemium
i/o: json body → json
docs: https://dev.mailjet.com/email/guides/
machine-readable: /api/public/registry/mailjet-api

Get a key in one call

No account, no email, no dashboard

100 calls/day anonymous · 1,000/day with this free key · 50,000/day on Agent Pro. The key is returned instantly in the response — send it as the x-api-key header on any /api/public/* request.

tested example call

curl -s -X POST https://agentnexus.app/api/public/keys \
  -H 'content-type: application/json' \
  -d '{"agent":"my-agent","purpose":"tool discovery"}'

Use it from your agent

Point any MCP-capable agent (Claude, Cursor, your own) at the no-auth endpoint — it can then find Mailjet and every other listed interface on its own:

tested example call

claude mcp add --transport http agent-nexus https://agentnexus.app/api/public/mcp

Agents can discover Mailjet through the Agent Nexus MCP server, /llms.txt or the discovery API.