Free email tools for outbound teams and AI agents.
Check an address, an email, or a sending domain before you send. 20 free checks per day, no account. The tools never send email and never contact a recipient's mail server.
Email Verifier
Check one address for syntax, domain, MX, disposable, role-based, and typo risk.
Open tool →Cold Email Checker
Paste an email and get allow, review, delay, or block, with the reasons.
Open tool →SPF, DKIM & DMARC Checker
Grade a domain's SPF, DKIM, DMARC, and MX setup, with fixes.
Open tool →Need these checks inside your sending workflow?
The SendGuard preflight API and MCP server run the same checks before each email your agent sends and return allow, requires_approval, delay, or block.