# Reacher

> Open-source Rust email verification tool and REST API backend

Reacher (formerly check-if-email-exists) is an open-source Rust library and REST API that verifies whether an email address exists without actually sending a message. It checks syntax, MX records, catch-all settings, disposable domains, and SMTP reachability, and can be self-hosted for free or used as a managed SaaS.

Website: https://reacher.email/

## What it is for

- Verify email lists before sending outreach campaigns to reduce bounce rates
- Validate user emails in real time during sign-up to prevent spam accounts
- Self-host an internal email verification backend to eliminate third-party SaaS costs

## Features

- Syntax validation following RFC specifications
- DNS and MX record lookup
- Disposable and temporary email domain detection
- SMTP mailbox existence check without sending an email
- Catch-all address detection
- REST API backend with client SDK examples in Node.js, Python, and Go
- Optional managed SaaS and SMTP proxy rotation infrastructure

## Pricing

Open source. Free and open source (MIT license) to self-host; paid managed SaaS and proxy plans available

## Details

- Type: GitHub repo
- Category: [Development](https://xiry.app/topics/development.md)
- Open source: yes
- Platforms: Self-hosted, API, Code library, Linux
- For: Developers and growth engineers building email verification into apps or outreach pipelines
- Alternative to: NeverBounce, ZeroBounce, MillionVerifier, Hunter
- Tags: email verification, rust, smtp, deliverability, self hosted, rest api

## Why it was saved

- [@mahanaicoach, 21 September 2026](https://www.instagram.com/reel/DdjfghctK7x/): Serves as a free, self-hostable alternative to paid email verification tools like MillionVerifier to clean cold email lead lists and avoid high verification fees.

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Updated 3 October 2026. Page: https://xiry.app/resources/reacher

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