# reacherhq/check-if-email-exists

Check if an email address exists without sending any email, written in Rust. Comes with a ⚙️ HTTP backend.

Repository: https://github.com/reacherhq/check-if-email-exists
Canonical: https://ross.abutalabs.com/products/check-if-email-exists
Homepage: https://reacher.email
Language: Rust
License: NOASSERTION
License Family: other
Topics: email, email-validation, email-verification, hacktoberfest, email-validation-api, email-verification-api, email-verifier
Last push: 2026-03-17T15:14:47+00:00

## Health v2 (maintenance only)
Score: 76/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 72, release rhythm 66, longevity 100
- inputs: {"age_days": 3417, "days_push": 169, "days_rel": 230, "gap_med": 1, "n_releases_24m": 30}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 9485, forks 685 (observed 2026-08-28T04:10:31.361557+00:00)

## What it is
A Rust library and CLI that checks whether an email address exists via SMTP/MX lookups without sending an actual email. It also ships as a Dockerized HTTP backend exposing an email verification API.

## Use cases
- verify if an email address exists before sending
- check email deliverability without sending email
- self-hosted email verification API
- validate email syntax and MX records
- detect disposable or catch-all email addresses
- clean up a mailing list of invalid emails

## When to choose
- you need SMTP-level email verification without sending messages
- you want a self-hosted alternative to paid email verification services
- you need both a Rust library and an HTTP API from one project

## When to avoid
- you only need simple syntax validation - a regex or lightweight validator suffices
- you cannot open outbound port 25 or run SMTP proxies
- you need high-volume verification without proxy infrastructure

## Facets
- artifact type: library
- maturity: active
- function: email, http-server, cli, api-framework
- domain: email, developer-tools, backend, apis
- platform: rust, cli, cross-platform, self-hosted
- tags: email-verification, smtp, mx-lookup, email-validation, disposable-email-detection, docker

## Member repositories
- reacherhq/check-if-email-exists (main) score 76

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:31.361557+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:22:03.106423+00:00, confidence not recorded.
  - readme: https://github.com/reacherhq/check-if-email-exists (fetched 2026-08-28T04:10:31.361557+00:00, sha a3d4bb1167b1)
  - homepage: https://reacher.email (fetched 2026-08-29T08:21:54.571968+00:00, sha 4eb5364cdb5d)
  - registry_crates: https://crates.io/api/v1/crates/check-if-email-exists (fetched 2026-08-29T08:21:54.575261+00:00, sha f53e6fcd2ab0)
- Data as of 2026-08-30T08:39:29.467469+00:00.