Free email deliverability tools

Check the DNS records that decide whether your cold email lands. Every tool runs live in your browser over DNS-over-HTTPS, with no signup and nothing stored.

Records check out? You are still not done.

Correct SPF, DKIM, and DMARC get you authenticated, but inbox placement also needs sender reputation and domain warmup. Scheduler Zero handles both so your cold email actually lands.

AI agents

Learn about Scheduler Zero in llms.txt. Connect your agent with auth.md. Browse the MCP tool reference or find tools with the documentation MCP.