Email blacklist checker
Check whether a domain or IPv4 address appears on the reputation lists used by mail systems.
How it works
Check public DNS blocklists
DNS-based blocklists publish IP reputation signals used by receiving mail servers. A listing is a diagnostic clue, not proof that every recipient will reject your mail.
- Resolve a domain to its current IPv4 addresses
- Query each supported DNS blocklist
- Show the exact listed IP addresses
- Keep each provider’s result separate
Use these checks during signup
The API returns allow, review, or block with the reasons behind it.