email-check

Full email posture for a domain: can it receive mail, and can it be spoofed? Runs MX, SPF and DMARC lookups together and returns a plain-language verdict alongside the raw records: can_receive_mail, spoofable, and a list of specific findings. Use this as the default check before emailing an unfamiliar domain, when judging whether inbound mail claiming to be from a domain could be forged, or when auditing your own domains. Prefer this over the single-record tools unless you already know which record you need.

{
  "type": "object",
  "properties": {
    "domain": {
      "type": "string",
      "x-in": "query",
      "example": "kaiv.ai",
      "description": "Domain to check, e.g. \"example.com\". A full email address is accepted and the domain is taken from it."
    }
  },
  "required": [
    "domain"
  ]
}

{
  "type": "object",
  "properties": {
    "mx": {
      "type": "object",
      "properties": {
        "found": {
          "type": "boolean",
          "description": "Whether any MX record exists."
        },
        "hosts": {
          "type": "array",
          "items": {
            "type": "object",
            "properties": {
              "host": {
                "type": "string",
                "description": "Mail exchanger hostname."
              },
              "priority": {
                "type": "integer",
                "description": "Lower is preferred."
              }
            }
          },
          "description": "MX hosts, lowest priority first."
        }
      }
    },
    "spf": {
      "type": "object",
      "properties": {
        "found": {
          "type": "boolean"
        },
        "record": {
          "type": "string",
          "description": "The raw SPF TXT record, or null when absent."
        },
        "strict": {
          "type": "boolean",
          "description": "True only for `-all`, the one strict answer."
        },
        "meaning": {
          "type": "string",
          "description": "What the qualifier means in practice."
        },
        "qualifier": {
          "enum": [
            "fail",
            "softfail",
            "neutral",
            "pass",
            "unspecified"
          ],
          "type": "string",
          "description": "The qualifier on the `all` mechanism."
        },
        "multiple_records": {
          "type": "boolean",
          "description": "More than one SPF record: receivers treat this as permerror, so SPF effectively fails."
        }
      }
    },
    "dmarc": {
      "type": "object",
      "properties": {
        "found": {
          "type": "boolean"
        },
        "policy": {
          "enum": [
            "none",
            "quarantine",
            "reject",
            "ignored",
            "unspecified"
          ],
          "type": "string",
          "description": "\"ignored\" means duplicate records cancelled the policy out."
        },
        "record": {
          "type": "string"
        },
        "meaning": {
          "type": "string"
        },
        "percent": {
          "type": "integer",
          "description": "The pct= tag; defaults to 100."
        },
        "protects": {
          "type": "boolean",
          "description": "False for p=none (monitoring only) and for duplicate records."
        },
        "all_records": {
          "type": "array",
          "items": {
            "type": "string"
          },
          "description": "Present only when more than one DMARC record exists."
        },
        "multiple_records": {
          "type": "boolean",
          "description": "RFC 7489 requires receivers to apply NO policy when more than one record exists."
        }
      }
    },
    "domain": {
      "type": "string"
    },
    "summary": {
      "type": "string",
      "description": "Plain-language verdict."
    },
    "findings": {
      "type": "array",
      "items": {
        "type": "string"
      },
      "description": "One line per specific problem; empty when the domain is correctly configured."
    },
    "spoofable": {
      "type": "boolean",
      "description": "True unless DMARC is present AND at an enforcing policy. Deliberately conservative: without enforcement a receiver has no instruction to reject forged mail, however good the SPF record is."
    },
    "checked_at": {
      "type": "string",
      "format": "date-time"
    },
    "can_receive_mail": {
      "type": "boolean",
      "description": "False when the domain publishes no MX records."
    }
  },
  "required": [
    "domain",
    "can_receive_mail",
    "spoofable",
    "summary"
  ]
}

DMARC record, policy, and whether it actually protects. Returns the DMARC TXT record at _dmarc.<domain>, its policy (none / quarantine / reject), the percentage it applies to, and whether that policy protects against spoofing. Also flags the case of MULTIPLE DMARC records, which RFC 7489 requires receivers to treat as no policy at all — a domain in that state is unprotected however strict its records look. A policy of "none" is monitoring only and does not stop forged mail. Use when assessing whether mail claiming to be from a domain can be trusted.

{
  "type": "object",
  "properties": {
    "domain": {
      "type": "string",
      "x-in": "query",
      "example": "kaiv.ai",
      "description": "Domain to check, e.g. \"example.com\". A full email address is accepted and the domain is taken from it."
    }
  },
  "required": [
    "domain"
  ]
}

{
  "type": "object",
  "properties": {
    "found": {
      "type": "boolean"
    },
    "domain": {
      "type": "string"
    },
    "policy": {
      "enum": [
        "none",
        "quarantine",
        "reject",
        "ignored",
        "unspecified"
      ],
      "type": "string",
      "description": "\"ignored\" means duplicate records cancelled the policy out."
    },
    "record": {
      "type": "string"
    },
    "meaning": {
      "type": "string"
    },
    "percent": {
      "type": "integer",
      "description": "The pct= tag; defaults to 100."
    },
    "protects": {
      "type": "boolean",
      "description": "False for p=none (monitoring only) and for duplicate records."
    },
    "all_records": {
      "type": "array",
      "items": {
        "type": "string"
      },
      "description": "Present only when more than one DMARC record exists."
    },
    "multiple_records": {
      "type": "boolean",
      "description": "RFC 7489 requires receivers to apply NO policy when more than one record exists."
    }
  },
  "required": [
    "domain"
  ]
}

Mail exchanger records for a domain. Returns the MX hosts in priority order and whether any exist. A domain with no MX records cannot receive mail, so sending to it will bounce. Use when you only need deliverability and not spoofing posture; use check_email_domain for the full picture.

{
  "type": "object",
  "properties": {
    "domain": {
      "type": "string",
      "x-in": "query",
      "example": "kaiv.ai",
      "description": "Domain to check, e.g. \"example.com\". A full email address is accepted and the domain is taken from it."
    }
  },
  "required": [
    "domain"
  ]
}

{
  "type": "object",
  "properties": {
    "found": {
      "type": "boolean",
      "description": "Whether any MX record exists."
    },
    "hosts": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "host": {
            "type": "string",
            "description": "Mail exchanger hostname."
          },
          "priority": {
            "type": "integer",
            "description": "Lower is preferred."
          }
        }
      },
      "description": "MX hosts, lowest priority first."
    },
    "domain": {
      "type": "string"
    },
    "can_receive_mail": {
      "type": "boolean"
    }
  },
  "required": [
    "domain"
  ]
}

SPF record and how strict it is. Returns the SPF TXT record, the qualifier on its `all` mechanism (fail / softfail / neutral / pass) and what that means in practice, plus whether more than one SPF record exists — which receivers treat as an error, leaving the domain unprotected. Use when diagnosing why mail from a domain is being rejected or marked.

{
  "type": "object",
  "properties": {
    "domain": {
      "type": "string",
      "x-in": "query",
      "example": "kaiv.ai",
      "description": "Domain to check, e.g. \"example.com\". A full email address is accepted and the domain is taken from it."
    }
  },
  "required": [
    "domain"
  ]
}

{
  "type": "object",
  "properties": {
    "found": {
      "type": "boolean"
    },
    "domain": {
      "type": "string"
    },
    "record": {
      "type": "string",
      "description": "The raw SPF TXT record, or null when absent."
    },
    "strict": {
      "type": "boolean",
      "description": "True only for `-all`, the one strict answer."
    },
    "meaning": {
      "type": "string",
      "description": "What the qualifier means in practice."
    },
    "qualifier": {
      "enum": [
        "fail",
        "softfail",
        "neutral",
        "pass",
        "unspecified"
      ],
      "type": "string",
      "description": "The qualifier on the `all` mechanism."
    },
    "multiple_records": {
      "type": "boolean",
      "description": "More than one SPF record: receivers treat this as permerror, so SPF effectively fails."
    }
  },
  "required": [
    "domain"
  ]
}