DNS & email security checker · free
A/MX/NS plus SPF, DKIM and DMARC with a grade and fixes.
Use it from code or an AI agent
Free JSON API: GET /api/v1/tools/dns?domain= · MCP server https://stabledomains.net/api/mcp · llms.txt · OpenAPI
FAQ
What do SPF, DKIM and DMARC do?
SPF lists servers allowed to send your mail, DKIM signs messages, and DMARC tells receivers what to do when checks fail. Together they stop spoofing and improve deliverability.
Why is no DKIM key found?
DKIM lives under a provider-specific selector. We test common ones (google, selector1/2, k1, s1…); pass ?dkim_selectors= to the API to test yours.
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