OneTimeSuite Blog · 2026

5 Free & Open-Source Alternatives to Mailchimp

Looking for a free or open-source alternative to Mailchimp? Postbird is the closest direct swap — MIT-licensed source on GitHub, or a $59 one-time packaged install. Since you're already auditing what you pay Mailchimp every month, here are four more pay-once tools from the same catalog worth a look while you're at it — different jobs, same idea: buy the software once instead of renting it forever.

1. Postbird — replaces Mailchimp

Lists, segments, a drag-block builder, throttled sending & open/click tracking — no per-contact pricing. $59 once vs Mailchimp's $20+/mo (grows with your list). Free on GitHub, or the packaged installer on Whop.

See Postbird → · Source on GitHub

2. Castport — Upload episodes, get a valid RSS feed, public pages, embeddable player & download stats. Pay once.

Replaces Transistor ($19/mo). $39 once. See Castport →

3. Inkpress — Split-pane markdown editor, 3 themes, server-side highlighting, RSS & SEO — one SQLite file.

Replaces Ghost ($9/mo). $29 once. See Inkpress →

4. Feedloft — Self-hosted Feedly alternative — folders, OPML, full-text search, one SQLite file.

Replaces Feedly ($8/mo). $24 once. See Feedloft →

5. Reelsnag — Paste a URL, pick a quality, queue it. Trim, MP3, subtitles, batch — all local.

Replaces Downloader subscription sites ($10–15/mo). $24 once. See Reelsnag →

Why this list is worth bookmarking

Every app above is a one-time purchase with MIT-licensed source, no accounts with us and no telemetry. None of them are trying to be the next Mailchimp — they're trying to be the last subscription you pay for that specific job.

Try Postbird — $59, once

Lists, segments, a drag-block builder, throttled sending & open/click tracking — no per-contact pricing.