bouncelens/email-check-api repository overview

⁠BounceLens email check API (self-hosted)

Check email addresses before you send to them or save them. Runs on your own server: no API key, no account, no per-check fees. Same checks and response format as the free checker at bouncelens.com⁠.

• Typos in the domain: [email protected] → did you mean [email protected]?
• Disposable / throwaway domains (~9,000 built in)
• Dead domains: domain doesn't exist, no mail server, or null MX
• Bad syntax, role addresses (info@, sales@), free providers, duplicates (Gmail dot/+tag variants)
• The mail provider behind the domain (Google, Microsoft, Proofpoint, …)

Tiny image (~3 MB compressed, built FROM scratch), runs as non-root.

⁠Run

docker run -d -p 8080:8080 bouncelens/email-check-api

⁠Use

curl 'localhost:8080/api/[email protected]'
curl -X POST localhost:8080/api/check -d '{"emails":["[email protected]","[email protected]"]}'

Each result has status: invalid (will bounce), risky (disposable, typo, no MX, DNS failed) or unconfirmed (format and domain OK; the mailbox itself is not checked), plus reasons, flags, did_you_mean, provider and mx.

Environment: PORT (default 8080), MAX_EMAILS (default 500).

Privacy: addresses never leave your server. Only the domain is looked up over DNS-over-HTTPS (Cloudflare 1.1.1.1). It never connects to the recipient's mail server.

⁠Links

• Website and free browser checker: bouncelens.com⁠
• Source (Go library + this API, MIT): github.com/bouncelens/go-email-check⁠
• MCP server for AI agents: github.com/bouncelens/mcp-email-check⁠