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ProbeKit MX Record Lookup
x402
ProbeKit MX Record Lookup is a paid API for AI agents from api.probekit.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-30).
Lists a domain's mail servers in preference order and detects null MX (RFC 7505) and unresolvable MX targets with coded findings.
Price / call$0.01
Success—
StatusUnknown
How this service works
List a domain's mail servers in preference order and detect null MX (RFC 7505) and MX targets that do not resolve, with coded findings. Use when an agent must find where mail for a domain is delivered or why a domain cannot receive mail.
Output
Returns an ordered list of MX records for the domain including hostname and priority, a flag indicating whether a null MX (RFC 7505) is present, and coded diagnostic findings for any MX targets that fail DNS resolution.
Example use cases
Diagnose undeliverable email domain
“We've been getting bounce-backs trying to email vendors at example-vendor.com — can you check their MX records and tell me if the domain is configured to receive mail or if it has a null MX blocking delivery?”
Mail server routing audit before send
“Before we launch this outbound campaign, can you pull the MX records for acmecorp.com and list the mail servers in priority order so I know where our messages will be routed?”
Detect misconfigured MX in onboarding check
“A new user signed up with their corporate domain bigclient.io — can you check its MX records and flag if any of the MX hosts don't resolve or if the domain has opted out of receiving mail with a null MX?”
Technical details
Endpoint
GEThttps://api.probekit.dev/v1/mail/mx?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to specifically inspect mail server configuration for a domain — either to route email correctly, diagnose delivery failures, or detect domains that have opted out of receiving mail via null MX. Prefer this focused MX endpoint over the full mail diagnostics report when you only need MX data and want lower cost and faster response. Use the sibling bulk endpoint when checking more than one domain at once.
Side effects
- Domain does not exist (NXDOMAIN) — returns error or empty MX result
- Domain has no MX records — returns empty list, possibly with null MX flag
- MX target hostnames do not resolve — flagged as coded findings in response
- Malformed or overly long domain input — rejected by schema validation
- Temporary DNS resolver failure — may return transient error
- Payment failure or missing x402 credentials — request rejected before processing
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object |
Tags
x402
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