Open-source alternatives guide · Updated 2026

Best open-source alternatives to Mailgun

Compare the best free and open-source alternatives to Mailgun — 6 verified projects with explicit catalog relationships. Inspect licenses, GitHub activity, self-hosting signals, and migration fit before you switch.

6verified alternatives
3self-hosted signals
3categories

Only explicit alternative relationships are shown—never inferred competitor claims.

Overview

This guide compares 6 verified open-source alternatives to Mailgun, including Listmonk, DoubleZero, Sessy, and Hyvor Relay.

Projects appear across Infrastructure, Data & Analytics, and Content & Collaboration. 3 options include a self-hosting signal — see the self-hosted catalog. Ranking follows public GitHub stars and recorded momentum—not vendor marketing. Compare projects side by side, then confirm license fit, migration effort, and operational ownership before adopting any option.

Strongest repository-activity signal: Listmonk · Jump to ranking · 22.1K stars · self-hostable

About Mailgun

Proprietary product with documented open-source alternatives cataloged on OpenSourceChoice. Compare licenses, repository activity, and self-hosting options befo

Ranked open-source alternatives to Mailgun

Compare capabilities, licensing, and ownership model. Stars help with discovery; they are not a security or product-fit guarantee.

Listmonk

Open-source alternative to Mailgun

InfrastructureAGPL-3.0Self-hosted

High performance, self-hosted, newsletter and mailing list manager with a modern dashboard. Single binary app.

High performance, self-hosted, newsletter and mailing list manager with a modern dashboard. Single binary app. Review the official repository, license, release activity, and deploy

Best for: Infrastructure teams
Deployment: Self-hostable
License: AGPL-3.0
Activity: Updated 4 days ago

Key capabilities

self-hosted

smtp email-marketing newsletter

DoubleZero

Open-source alternative to Mailgun

InfrastructureAGPL-3.0

A markdown email micro service for the people!

A markdown email micro service for the people! Review the official repository, license, release activity, and deployment documentation before production adoption.

Best for: Infrastructure teams
Deployment: Inspectable source
License: AGPL-3.0
Activity: Updated 2 years ago

Key capabilities

Elixir

JavaScript

NodeJS

Sessy

Open-source alternative to Mailgun

Data & AnalyticsLicense not declaredSelf-hosted

Open-source email observability for AWS SES

Open-source email observability for AWS SES Review the official repository, license, release activity, and deployment documentation before production adoption.

Best for: Data teams
Deployment: Self-hostable
License: License not declared
Activity: Updated 45 hours ago

Key capabilities

ruby

rails amazon-ses

Hyvor Relay

Open-source alternative to Mailgun

InfrastructureAGPL-3.0Self-hosted

✉️ Open-Source Email API for Developers. Cloud & Self-hosted Alternative to SES, Mailgun, SendGrid.

✉️ Open-Source Email API for Developers. Cloud & Self-hosted Alternative to SES, Mailgun, SendGrid. Review the official repository, license, release activity, and deployment docume

Best for: Infrastructure teams
Deployment: Self-hostable
License: AGPL-3.0
Activity: Updated 2 days ago

Key capabilities

smtp

PHP

Github Actions

Wraps

Open-source alternative to Mailgun

Content & CollaborationLicense not declared

AWS Email, SMS, & CDN, simple.

AWS Email, SMS, & CDN, simple. Review the official repository, license, release activity, and deployment documentation before production adoption.

Best for: Knowledge teams
Deployment: Inspectable source
License: License not declared
Activity: Updated Jul 14, 2026

Key capabilities

typescript

cli

aws

AgentMail

Open-source alternative to Mailgun

Content & CollaborationLicense not declared

Open-source TypeScript project maintained on GitHub.

Open-source TypeScript project maintained on GitHub. Review the official repository, license, release activity, and deployment documentation before production adoption.

Best for: Knowledge teams
Deployment: Inspectable source
License: License not declared
Activity: Updated Jul 15, 2026

Key capabilities

TypeScript

Github Actions

JavaScript

How to choose a Mailgun alternative

Map must-have capabilitiesList the workflows in Mailgun you cannot drop during migration.

Verify the licenseConfirm it fits your use, distribution, and compliance model. Browse license briefs.

Run a proof of conceptTest real data, integrations, clients, and failure modes. Use Compare for side-by-side checks.

Plan ownershipAssess upgrades, backups, support, and an exit path. Read when self-hosting is worth it.

Frequently asked questions about Mailgun alternatives

What are the best open-source alternatives to Mailgun?

OpenSourceChoice currently lists 6 projects with an explicit alternative relationship to Mailgun. Catalog highlights include Listmonk, DoubleZero, and Sessy. Rankings follow public GitHub stars and recorded momentum—not paid placement. Match capabilities and license fit to your workflow before adopting any option.

Are open-source alternatives to Mailgun free?

Most catalogued alternatives publish source under OSI or source-available licenses and are free to inspect. Hosting, commercial support, or cloud model APIs may still cost money. Always read the project license for your use case.

Can I self-host an alternative to Mailgun?

3 options in this list carry a self-hosting signal. Confirm the official install guide, backups, upgrades, and hardening steps before production.

How should I evaluate Mailgun alternatives?

Map must-have Mailgun workflows, verify license and compliance fit, run a proof of concept with real data and integrations, then plan ownership for upgrades, backups, support, and an exit path.