Mailgun

Judgement

What it is

Building block

What it does

Email API for sending, receiving and tracking email, including inbound routing and email validation.

Adopt it when

Developers need to send transactional email and also parse inbound email into their application.

Watch out

Pricing has risen and the free tier is small.

Ready for

Production-ready

Runs as

Cloud service

What the license allows

Closed source: you use it under the maker's terms and cannot change or resell the code.

Judged on 2026-11-03 from the maker's description and Wikipedia. The license and age lines are worked out directly.

Open-source alternatives to Mailgun

1. 1
   React Email resend

   💌 Build and send emails using React

   Developer tool Production-ready Your team writes React and wants maintainable, previewable email templates for any sending provider.

   ★ 20k MIT TypeScript Active, pushed 3 days ago
2. 2
   MJML mjmlio

   MJML: the only framework that makes responsive email easy

   Framework or platform Production-ready Anyone who hand-codes HTML emails and wants them to render in Outlook and Gmail without table hacks.

   ★ 18k MIT JavaScript Active, pushed 10 days ago
3. 3
   Postal postalserver

   📮 A fully featured open source mail delivery platform for incoming & outgoing e-mail

   Complete system Production-ready You send large volumes of transactional email and want your own Sendgrid-style platform on your own IPs.

   ★ 17k MIT Ruby Active, pushed 4 days ago
4. 4
   Plunk useplunk

   The Open-Source Email Platform

   Complete system Usable You want one open-source tool for both product emails and newsletters on AWS SES.

   ★ 5.6k AGPL-3.0 TypeScript Active, pushed yesterday
5. 5
   React Email Editor unlayer

   Drag-n-Drop Email Editor Component for React.js

   Integration Production-ready Your product needs users to design emails or newsletters inside it.

   ★ 5.3k MIT TypeScript Active, pushed 2 days ago
6. 6
   useSend usesend

   Open source alternative to Resend, Sendgrid, Postmark etc.

   Complete system Usable You want Resend or Postmark convenience at SES prices, hosted or self-hosted.

   ★ 4.8k AGPL-3.0 TypeScript Active, pushed 3 days ago
7. 7
   Posta goposta

   Self-hosted email delivery platform that enables applications to send emails via HTTP APIs while handling SMTP delivery, templates, storage, security, and analytics. Fully self-hostable alternative to services like SendGrid or Mailgun.

   Complete system Experimental You want your apps' transactional email behind one self-hosted API with logs and templates.

   ★ 633 AGPL-3.0 Go Active, pushed yesterday
8. 8
   Mrml jdrouet

   Implementation of mjml in rust

   Building block Usable You render MJML at high volume or outside Node.js and want speed.

   ★ 510 MIT HTML Active, pushed 17 days ago
9. 9
   Larasend savvyagents

   Self-hosted transactional email platform — send through your own AWS SES account, keep the dashboard, API keys, delivery logs, and webhooks on your own infrastructure.

   Complete system Experimental A Laravel team wants Resend-style tooling while keeping data and costs on its own SES account.

   ★ 440 MIT PHP Active, pushed 3 months ago
10. 10
    Elements unlayer

    React components for transactional emails, landing pages, invoices and PDFs: email-safe HTML, responsive web HTML, and print-ready PDF HTML from one component tree.

    Building block Experimental You produce emails, invoices and documents from React and want one set of components for all of them.

    ★ 423 MIT TypeScript Active, pushed 13 days ago

Every alternative to Mailgun

Other commercial email sending platforms and email templating tools

1. 1
   SendGrid Twilio

   SendGrid's trusted email API and marketing campaigns platform is now available through Twilio.com.

   Building block Production-ready An application needs to send high volumes of email through a well-known API.

   283 readers a month Since 2009 Commercial
2. 2
   Amazon SES Amazon Web Services

   Amazon Simple Email Service (SES) is a cost-effective, flexible, and scalable email service provider that allows developers to send email from within any application.

   Building block Production-ready You send large volumes of email, run on AWS and can manage deliverability yourself.

   Commercial
3. 3
   Postmark ActiveCampaign

   Send transactional and marketing emails and get them to the inbox on time, every time. Postmark is a fast and reliable email delivery service for developers.

   Building block Production-ready Password resets, receipts and other critical app email must arrive quickly and reliably.

   Commercial
4. 4
   Resend Resend

   The best way to reach humans instead of spam folders. Deliver transactional and marketing emails at scale.

   Building block Usable A modern web app team, especially using React and Next.js, wants a clean email API that is quick to integrate.

   Commercial

Under it

Every program, Mailgun included, runs on a microchip.

How compilers were built, back to punched paper tape