The archive · Developer & Business Tools · Product decision · 2021–2026
Reacher's open-source email check bet draws HN in 2021; repo reaches 9.6k stars by 2026
Reacher's Rust checker verifies an email exists without sending one; the open-source bet drew 479 HN points in 2021 and 9.6k stars by 2026
Reacher
What the business is
Reacher (reacherhq) is the company behind check-if-email-exists, an open-source Rust library, CLI and Docker HTTP backend that tells whether an email address can receive mail — syntax, MX, SMTP, catch-all, disposable-address and breach checks — without sending any email; it monetizes with a hosted SaaS and commercial licenses.
How it started
check-if-email-exists was built and published as an open-source Rust project by Reacher (reacherhq), positioned in its README as the open-source alternative to paid services such as Hunter, verify-email.org and email-checker.net — offering a CLI, a Docker-run HTTP backend and a library that check deliverability without sending email, alongside a live demo at reacher.email.
What happened
The project hit Hacker News on 2021-07-01 with 479 points and 250 comments; the thread debated the SMTP technique, CAN-SPAM and the Have I Been Pwned signal, while the README kept offering three non-SaaS ways to run it and pointed paying users to a commercial license and the hosted SaaS No2Bounce.
How it ended up
As of the 2026-09-05 snapshot the project and company are still live: the repository shows 9.6k stars, 695 forks and 1,410 commits, and the README still directs self-hosters to a commercial license at reacher.email/pricing and teams to the hosted SaaS No2Bounce.
Background
check-if-email-exists is Reacher's open-source Rust tool for a single question teams ask constantly: will an email I send actually arrive? It combines syntax checks, MX records, SMTP server checks, catch-all detection, disposable-address and breach lookups to return a reachability verdict — without sending any email.
Reacher published the engine as a library, CLI and Docker HTTP backend so any developer could run verification on their own infrastructure, and positioned it in the README as the open-source alternative to paid services such as Hunter, verify-email.org and email-checker.net, with a live demo at reacher.email.
On 2021-07-01 the repository drew 479 points and 250 comments on Hacker News. By the 2026-09-05 snapshot it showed 9.6k stars, 695 forks and 1,410 commits; the README still directed self-hosters to a commercial license at reacher.email/pricing and paying users to the hosted SaaS No2Bounce.
What has to be true
- Reacher picked a question every team with a signup form or a mailing list asks, so the open-source repo had built-in demand before any marketing.
- By open-sourcing the engine it made run-it-yourself the default, leaving the paid convenience layer — hosted API and licenses — as the only reason to buy.
- The HN thread stress-tested the SMTP technique and its legal edge cases in public, the kind of scrutiny that builds trust in a verification tool.
- The no-email-sent constraint protected deliverability reputation, the very metric the tool's customers were trying to protect.
What can be applied
Give the hard technical work away open-source and sell the convenience layer — hosted API, commercial license — because developer trust, not code secrecy, is the moat in dev tools
Aftermath
As of the 2026-09-05 snapshot, check-if-email-exists is still live and maintained: the repository shows 9.6k stars, 695 forks and 1,410 commits, and the README still presents the dual-license model — AGPL-3.0 for open-source projects, a commercial license at reacher.email/pricing for proprietary use — plus the Docker backend, CLI and library, and the hosted SaaS No2Bounce for teams that want a friendly web interface.
Sources
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Your turn
You just read one. Describe what you are building, and see who is betting on the same thing.
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