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Postmark alternatives · Email Sending

Open-source alternatives to Postmark

Postmark is not described as open source on its own site. 8 of the 50 other email sending services in this directory are open source, according to their own sites.

Postmark has a free plan. Paid plans start at $15 per month for 10,000 emails. All of them are free or have a free plan.

8 tools · Listings checked up to Nov 13, 2026 · Where the facts come from

How each one differs from Postmark

  1. Forward Email

    Open-source email forwarding and hosting for custom domains

    • Forward Email starts at $3 per month for unlimited domains. Postmark starts at $15 per month for 10,000 emails.
    • Only Forward Email lists macOS, Windows, Linux, iOS and Android apps.
    • Forward Email is open source and self-hostable, according to its own site.
    • Postmark also covers dMARC and transactional email.
    Forward Email vs PostmarkForward Email pricing and details

  2. Hyvor Relay

    Open-source email API you can self-host

    • Hyvor Relay starts at €10,000 per year and up (Enterprise License). Postmark starts at $15 per month for 10,000 emails.
    • Hyvor Relay is open source and self-hostable, according to its own site.
    • Postmark also covers dMARC.
    Hyvor Relay vs PostmarkHyvor Relay pricing and details

  3. useSend

    Open-source email sender built on Amazon SES

    • useSend starts at $10 per month, then pay as you go. Postmark starts at $15 per month for 10,000 emails.
    • useSend is open source and self-hostable, according to its own site.
    • useSend also covers email campaigns.
    • Postmark also covers dMARC.
    useSend pricing and details

  4. Plunk

    Open-source email platform for transactional and marketing mail

    • Plunk starts at $0.001 per email sent. Postmark starts at $15 per month for 10,000 emails.
    • Plunk is open source and self-hostable, according to its own site.
    • Plunk also covers workflow automation and email campaigns.
    • Postmark also covers dMARC.
    Plunk pricing and details

  5. Novu

    Open-source notification infrastructure for apps and agents

    • Novu starts at $30 per month for 30,000 workflow runs. Postmark starts at $15 per month for 10,000 emails.
    • Novu is open source, according to its own site.
    • Novu also covers workflow automation.
    • Postmark also covers dMARC.
    Novu pricing and details

  6. Nodemailer

    Free Node.js library for sending email over SMTP and other transports

    • Nodemailer is free. Postmark starts at $15 per month for 10,000 emails.
    • Nodemailer is open source, according to its own site.
    • Postmark also covers dMARC.
    Nodemailer pricing and details

  7. KumoMTA

    Open-source mail server for high-volume, self-run email sending

    • KumoMTA starts at $5,000 per billion messages per year for Silver support. Postmark starts at $15 per month for 10,000 emails.
    • Only KumoMTA lists a Linux app.
    • Only Postmark lists a web app.
    • KumoMTA is open source and self-hostable, according to its own site.
    KumoMTA pricing and details

  8. FluentSMTP

    Free WordPress plugin for sending site email through your provider

    • FluentSMTP is free. Postmark starts at $15 per month for 10,000 emails.
    • FluentSMTP is open source, according to its own site.
    • FluentSMTP also covers reports.
    • Postmark also covers dMARC.
    FluentSMTP pricing and details

Common questions

Is there an open-source alternative to Postmark?

Yes. Forward Email, Hyvor Relay, useSend, Plunk, Novu, Nodemailer, KumoMTA and FluentSMTP are open source, according to their own sites.

Is Postmark open source?

Postmark is not described as open source on its own site. The listing was checked on Oct 18, 2026 against the pages it cites.

When was this checked?

Each listing shows its own date. On this page they run from Oct 18, 2026 to Nov 13, 2026. Vendors change prices and plans without notice, so confirm on their site before you buy.

This page is built from the listings. A tool is here because its listing says so, and the order is how close each is to Postmark: the alternatives its listing names first, then the tools that share the most features with it.