Alternatives to Postal
Open-source, self-hosted mail delivery platform with a REST API, comparable to Mailgun or
Postal ranks #12 of 12 in Transactional email APIs, with an Alt Score of 78. It is licensed under MIT, free from Free and available on Linux. 10 of 12 checklist rows are verified against a public source.
Postal is a fully-featured open-source mail delivery platform you run on your own servers, providing a REST API, SMTP, web UI for mail logs, webhooks for delivery/bounce events, and spam/virus scanning integrations (SpamAssassin, rspamd, ClamAV). It is explicitly pitched as a self-hosted alternative to SendGrid, Mailgun, and Postmark for teams that want to own their sending infrastructure and IP reputation.
Developers and organizations who want to run their own outbound and inbound mail infrastructure for their websites or applications instead of relying on a third-party SaaS email API provider, and who are able to operate a dedicated Linux server.
A self-hosted, MIT-licensed mail server distributed as Docker containers, providing an SMTP relay and a JSON HTTP API for sending mail, DKIM signing, a built-in suppression list, bounce and return-path handling, click/open tracking, IP pool management, DNS health monitoring, and webhooks for message lifecycle events (sent, delayed, failed, held, bounced, clicked, opened).
You install Postal via Docker Compose on your own server (minimum 4GB RAM, 2 CPU cores, outbound port 25 open) and configure DNS records (SPF, DKIM, MX, return-path) for the sending domains. Outgoing mail is submitted either through SMTP credentials or the HTTP API; incoming mail can be forwarded to HTTP endpoints, other SMTP servers, or other e-mail addresses, and delivery/engagement events are pushed out to your application via configurable webhooks. Administration (servers, credentials, IP pools, tracking domains, logs) is done through Postal's own web interface.
Why people leave Postal
Dashed reasons are sourced facts; the rest are opinions. Vendors can dispute.
Sign in to add a reason — new reasons go through moderation before appearing.
Ranked alternatives
Ordered by Alt Score. Click any score to see the breakdown.
Elastic Email is a long-running email delivery service offering a REST API and SMTP relay for transactional sending, along with drag-and-drop templates, suppression list management, and delivery/engag.
MailerSend is a developer-focused transactional email service offering REST API and SMTP relay, dynamic templates, inbound email routing, domain management, and built-in analytics.
Mailgun (by Sinch) is a developer-focused email sending platform with a REST API and SMTP, inbound routing and parsing, templates, deliverability tooling, dedicated IPs, webhooks, and detailed logs an.
Amazon SES (Simple Email Service) is a scalable, pay-as-you-go email sending service from AWS, offering an API and SMTP interface, deliverability and reputation tooling, suppression handling, dedicate.
Mailtrap is a transactional email sending and testing platform used by product and dev teams to send app-triggered emails via REST API or SMTP, plus a sandbox for previewing emails before they hit pro.
Resend is a developer-first transactional email platform offering a clean REST API and SMTP, React-based email templates, webhooks, deliverability tooling, and analytics for sending product and notifi.
SMTP2GO provides SMTP relay and a REST API for sending transactional and bulk email, routed through multiple global data centers for redundancy.
SendGrid (a Twilio company) is an email delivery platform for both transactional and marketing email, offering a REST API and SMTP relay, templates, deliverability and validation tooling, dedicated IP.
ZeptoMail is Zoho's purpose-built transactional email service, separate from its marketing tools, offering a REST API and SMTP relay for app-triggered emails such as receipts and password resets.
Postmark is a transactional email service focused on speed and deliverability, providing a REST API and SMTP relay, templates, inbound parsing, webhooks, detailed message logs, and separate transactio.
Feature comparison
Rows come from the Transactional email APIs checklist (16 rows). Human-verified cells only. ? means the value has not been verified.
| Transactional email APIs checklist | Postal | Elastic Email | MailerSend | Mailgun | Amazon SES | Mailtrap |
|---|---|---|---|---|---|---|
| Pricing model | ||||||
| Starts at | ||||||
| License | ||||||
| Platforms | ||||||
| REST API | ||||||
| SMTP relay | ||||||
| Deliverability tooling | ||||||
| Templates | ||||||
| Inbound email parsing | ||||||
| Webhooks / events | ||||||
| Suppression & bounce handling | ||||||
| Dedicated IPs | ||||||
| Analytics / logs | ||||||
| SDKs | ||||||
| EU data residency | ||||||
| Free tier volume |
Every fact and feature listed for Postal is verified against its own pages. Each alternative is sourced on its own page.
-
Starts at Free verified 2026-07-30
No paid tier exists; same reasoning as pricing_model.
open source and ready for you to run on your own servers
https://raw.githubusercontent.com/postalserver/postal/main/README.md -
Status active verified 2026-07-30
CHANGELOG shows regular tagged releases (3.3.5 on 2026-02-01, 3.3.6 on 2026-04-28, 3.3.7 on 2026-06-03) including security fixes; GitHub repository metadata (api.github.com/repos/postalserver/postal)
## [3.3.7](https://github.com/postalserver/postal/compare/3.3.6...3.3.7) (2026-06-03)
https://raw.githubusercontent.com/postalserver/postal/main/CHANGELOG.md -
License MIT verified 2026-07-30
Software"), to deal in the Software without restriction" — File is named MIT-LICENCE in the repo root; text is the standard MIT License wording. Copyright lines: Krystal Hosting Ltd (2017-2024), Adam Cooke (2024), Charlie Smurthwaite (2024).
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the
https://raw.githubusercontent.com/postalserver/postal/main/MIT-LICENCE -
Pricing model Free verified 2026-07-30
postalserver.io (the official site) permanently redirects to github.com/postalserver/install and there is no pricing page anywhere on the vendor's domains; Postal is MIT-licensed self-hosted software
Postal is a complete and fully featured mail server for use by websites & web servers. Think Sendgrid, Mailgun or Postmark but open source and ready for you to run on your own servers.
https://raw.githubusercontent.com/postalserver/postal/main/README.md -
Platforms Linux verified 2026-07-30
Docs are technically OS-agnostic (Docker is the only host requirement), but the same page recommends a dedicated server with 4GB RAM/2 CPU cores and open outbound port 25, which in practice means a Li
It doesn't matter what operating system you choose as long as you are able to install Docker on it (see next section).
https://docs.postalserver.io/getting-started/prerequisites -
REST API Yes verified 2026-07-30
The HTTP API allows you to send messages to us using JSON over HTTP. You can either talk to the API using your current HTTP library or you can use one of the pre-built libraries.
https://docs.postalserver.io/developer/api -
SMTP relay Yes verified 2026-07-30
For sending outgoing emails through the Postal SMTP server you will need to generate a credential through the Postal web interface.
https://docs.postalserver.io/features/smtp-authentication -
Deliverability tooling Yes verified 2026-07-30
Feature list also lists DKIM signing of outbound messages and per-server send-limit configuration as related deliverability controls.
Built-in DNS checking and monitoring to ensure domains you send mail from are configured correctly for maximum deliverability.
https://docs.postalserver.io/welcome/feature-list -
Templates No verified 2026-07-30
No template engine, stored template, or merge-tag/personalization feature is documented anywhere in the docs or the feature list (docs.postalserver.io/welcome/feature-list); the API only accepts indiv
There are two ways to send a message - you can either provide each attribute needed for the e-mail individually or you can craft your own RFC 2822 message and send this instead.
https://docs.postalserver.io/developer/api -
Inbound email parsing Yes verified 2026-07-30
The 'processed' JSON payload documented on this page includes parsed subject, from, to, plain_body, html_body, message_id, spam_status and decoded attachments.
You can choose whether to receive the raw message (raw) or have it as a JSON dictionary (processed).
https://docs.postalserver.io/developer/http-payloads -
Webhooks / events Yes verified 2026-07-30
Documented events: MessageSent, MessageDelayed, MessageDeliveryFailed, MessageHeld, MessageBounced, MessageLinkClicked, MessageLoaded, DomainDNSError.
Postal supports sending webhooks over HTTP when various events occur during the lifecycle of a message.
https://docs.postalserver.io/developer/webhooks -
Suppression & bounce handling Yes verified 2026-07-30
Bounce handling detailed separately at docs.postalserver.io/other/auto-responders-and-bounces: bounces route to a dedicated return-path address and trigger a MessageBounced webhook.
Built-in suppression list to avoid sending mail to recipients that don't exist or can't accept e-mail.
https://docs.postalserver.io/welcome/feature-list -
Dedicated IPs Yes verified 2026-07-30
Self-hosted context: since you run Postal on your own server(s), all sending IPs already belong to you (never shared with other Postal users). On top of that, Postal lets you group your own IPs into n
Postal supports sending messages from different IP addresses. This allows you to configure certain sets of IPs for different mail servers or send from different IPs based on the sender or recipient ad
https://docs.postalserver.io/features/ip-pools -
Analytics / logs Yes verified 2026-07-30
Same page also states: "Complete logging so delivery issues can easily be identified" and "Mail server wide search tools to find messages that need investigation."
Graphs and stats showing volume of incoming and outgoing mail.
https://docs.postalserver.io/welcome/feature-list -
SDKs Yes verified 2026-07-30
Listed languages/frameworks: Ruby, Rails, Ruby (mail gem), PHP, Node, Java, .Net, .NET Core, Go, Elixir (via Swoosh), Drupal, Python. Page notes these aren't all developed by the Postal team.
There are a number of client libraries available to help send e-mail using the Postal platform.
https://docs.postalserver.io/developer/client-libraries
FAQ
Yes. Elastic Email, MailerSend and Mailgun have a free tier or are fully free. Free-tier limits in the comparison table are verified and dated.
useSend — every license claim links its source.