---
title: "SPF / DKIM / DMARC check"
full: true
_openapi:
  method: POST
  toc: []
  structuredData:
    headings: []
    contents:
      - content: "Audit sending domain authentication records against RFC standards. Evaluates SPF mechanism limits, DKIM cryptographic public keys, DMARC alignment policies, and MX server reachability."
_apiData:
  document: "https://reloop.sh/api/tools/openapi/json"
  operationData: [{"path":"/api/tools/v1/auth-checker","method":"post"}]
  parameterList: [{"name":"domain","type":"string","required":true,"description":"The sending domain name to check email authentication for.","location":"body","minLength":1,"maxLength":255,"example":"stripe.com"},{"name":"selector","type":"string","required":false,"description":"Optional DKIM selector (e.g. s1, google, default, k1).","location":"body","maxLength":100,"example":"s1"}]
  responseMap: {"200":{"description":"Response for status 200","schema":{"domain":"send.example.com","resolvedAt":"2026-03-23T10:00:00.000Z","responseTimeMs":0,"score":0,"grade":"example_grade","verdict":"fully_aligned","verdictLabel":"example_verdictLabel","spf":{"status":"pass","published":true,"rawRecord":"example_rawRecord","qualifier":"example_qualifier","lookupCount":0,"mechanisms":["example_mechanisms"],"includes":["example_includes"],"ip4":["example_ip4"],"ip6":["example_ip6"],"warnings":["example_warnings"]},"dkim":{"status":"pass","published":true,"selector":"example_selector","rawRecord":"example_rawRecord","publicKey":"example_publicKey","keyLength":0,"algorithm":"example_algorithm","testedSelectors":["example_testedSelectors"],"warnings":["example_warnings"]},"dmarc":{"status":"pass","published":true,"rawRecord":"example_rawRecord","policy":"example_policy","subdomainPolicy":"example_subdomainPolicy","percentage":0,"rua":["example_rua"],"ruf":["example_ruf"],"dkimAlignment":"example_dkimAlignment","spfAlignment":"example_spfAlignment","warnings":["example_warnings"]},"mx":{"status":"pass","published":true,"provider":"example_provider","records":[{"exchange":"example_exchange","priority":0}],"warnings":["example_warnings"]},"bimi":{"status":"pass","published":true,"rawRecord":"example_rawRecord","svgUrl":"example_svgUrl","vmcUrl":"example_vmcUrl"},"mtaSts":{"status":"pass","published":true,"rawRecord":"example_rawRecord","mode":"example_mode"},"diagnostics":[{"id":"con_123456789","name":"Newsletter","category":"spf","status":"pass","message":"Contact already exists","details":"example_details"}]}},"400":{"description":"Response for status 400","schema":{"message":"Contact already exists","why":"A contact with this email already exists in your organization.","fix":"Use a different email address or update the existing contact instead.","link":"https://reloop.sh/docs/api/contacts"}},"429":{"description":"Response for status 429","schema":{"message":"Contact already exists","why":"A contact with this email already exists in your organization.","fix":"Use a different email address or update the existing contact instead.","link":"https://reloop.sh/docs/api/contacts"}},"500":{"description":"Response for status 500","schema":{"message":"Contact already exists","why":"A contact with this email already exists in your organization.","fix":"Use a different email address or update the existing contact instead.","link":"https://reloop.sh/docs/api/contacts"}}}
  codeSamples: []
---
> For the complete documentation index, see [llms-docs.txt](/llms-docs.txt) or the site index [llms.txt](/llms.txt). Full docs corpus: [llms-full-docs.txt](/llms-full-docs.txt). Prefer markdown URLs (append `.md`) for agent consumption. Product skill: [skill.md](/skill.md).


{/* This file was generated by the OpenAPI doc generator. Do not edit this file directly. Run `bun run generate:api-docs` to regenerate. */}

<APIPage />