What is the top free pick among email tools?

Plunk leads the Stack Gems list for email tools. Verdict: AGPL email with a real 1k hosted free tier. Branding stays until you pay.

How many email tools does Stack Gems review?

5: 5 free or open source. Each review has a verdict and an honest Catch; no tool pays for its spot.

Which email tools can I self-host for free?

Plunk, Postal, Hyvor Relay, Mailu and Mailpit.

Which email tools have the most GitHub stars?

Postal (16.9k), Mailpit (10.7k), Mailu (7.6k), per GitHub on 2026-10-19. Stars measure attention, not fit; read the Catch.

Best of · Comms

Best email tools (2026)

Stack Gems reviews 5 email tools: 5 free or open source. These are the top 5, each with its verdict and the Catch we would want to know before installing it.

Order: free and open source first, then hosted products with a real free tier, then paid-led; catalog order inside each group, with quiet or archived repos last. Not a score, and no tool pays for its place.

5 reviewed · 5 shown in full

1.PlunkAGPL-3.0 transactional email, workflows, and broadcasts
Free / OSS · Freemium · 5.5k GitHub stars
VerdictAGPL email with a real 1k hosted free tier. Branding stays until you pay.
CatchAGPL-3.0 is copyleft. Hosted Free keeps Plunk branding. This is not Resend at volume — 1k/mo is the free wall, then $0.001/email. Self-host means you bring SES or equivalent.
2.PostalMIT self-hosted mail delivery: SMTP + HTTP API
Free / OSS · OSS/MIT · 16.9k GitHub stars
VerdictMIT self-host mail. Free to run; deliverability is your ops.
CatchSelf-hosted mail delivery SMTP+HTTP API — not Resend hosted tx email, not Plunk Node email, not Listmonk newsletter app. You own deliverability and IP reputation. Distinct from Resend, Plunk, and Listmonk.
3.Hyvor RelayAGPL-3.0 email relay; Self-Hosted Free Forever unlimited
Free / OSS · AGPL-3.0 · 918 GitHub stars
VerdictAGPL email relay. Self-host free forever; no Cloud free claim.
CatchCloud is not free. Self-host unlimited is the pitch. Vs Postal full mail server and Plunk Node email. Distinct from Postal and Plunk.
4.MailuMIT full mailbox stack: SMTP/IMAP/webmail — not tx API
Free / OSS · OSS/MIT · 7.6k GitHub stars
VerdictMIT mailbox suite. Free to run; ops-heavy vs a tx email API.
CatchFull mailbox SMTP/IMAP/webmail — not Resend/Plunk/Postal transactional-or-relay API. Ops-heavy: DNS, TLS, spam, storage. Distinct from Postal, Plunk, and Resend.
5.MailpitMIT local/CI SMTP sink — MailHog successor, not delivery
Free / OSS · OSS/MIT · 10.7k GitHub stars
VerdictMIT MailHog successor for local/CI. Free forever; not a mailer.
CatchSink only — not delivery. Not Resend SaaS, not Postal/Listmonk outbound. Do not point production MX here. Distinct from Resend/Postal/Listmonk.

FAQ

What is the top free pick among email tools?: Plunk leads the Stack Gems list for email tools. Verdict: AGPL email with a real 1k hosted free tier. Branding stays until you pay.
How many email tools does Stack Gems review?: 5: 5 free or open source. Each review has a verdict and an honest Catch; no tool pays for its spot.
Which email tools can I self-host for free?: Plunk, Postal, Hyvor Relay, Mailu and Mailpit.
Which email tools have the most GitHub stars?: Postal (16.9k), Mailpit (10.7k), Mailu (7.6k), per GitHub on 2026-10-19. Stars measure attention, not fit; read the Catch.
What is the catch with Plunk?: AGPL-3.0 is copyleft.

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