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Mailgun Flex (Free)

100 emails a day with a real REST API, no credit card, from a battle-tested provider

Mailgun is a long-standing transactional email service with a powerful REST API for sending, routing, and validating mail. Its Flex free plan gives 100 emails per day with one custom sending domain, tracking, analytics, and webhooks, and does not require a credit card.

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Free tier

Flex free plan: 100 emails/day, 1 sending domain, 1-day log retention, no credit card

Rate limits

No fixed RPS published; free plan is gated by the 100 emails/day cap and unverified-account sending restrictions

Auth

API key

Base URL

https://api.mailgun.net/v3

What you'd build with it

Send transactional email from a backend or automation using basic-auth REST
Route and parse inbound email into a workflow
Track opens, clicks, and bounces via the events API
Use the EU region endpoint (api.eu.mailgun.net) for data-residency needs

Key endpoints

POST/{domain}/messagesSend an email via the sending domain (multipart form)
GET/{domain}/eventsQuery delivery, open, click, and failure events
GET/address/validateValidate a single email address (separate quota)
POST/routesCreate an inbound routing rule for received mail

Members

Members get the runnable recipe

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