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DNS MX Priority Sort
x402
DNS MX Priority Sort is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-20).
Sorts a list of DNS MX (mail exchange) records by preference value, preserving original order for equal-priority entries, and returns a deterministic pass/advisory verdict.
Price / call$0.001
Success—
StatusUnknown
How this service works
DNS MX Priority Sort: DNS MX Priority Sort sorts MX exchanges by preference while preserving equal-priority order from bounded caller-supplied values without an external provider. Call DNS MX Priority Sort before accepting, caching, redirecting, or retrying a caller-supplied web response. Returns normalized web evidence, the computed finding, and an explicit pass or advisory status for DNS MX Priority Sort as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-party, statel…
Output
Returns a deterministic versioned JSON object containing: the normalized and sorted MX records ordered by ascending preference value (with stable ordering preserved for equal-priority entries), the computed priority ranking, and an explicit pass or advisory status indicating whether the input was well-formed and sortable.
Example use cases
Email delivery failover ordering
“I have these MX records from a DNS lookup and need to know which mail server to try first, second, and third for delivery — can you sort them by priority and tell me the correct order? Records: [{"exchange":"mx1.domain.com","priority":20},{"exchange":"mx2.domain.com","priority":10},{"exchange":"mx3.domain.com","priority":20}]”
Validating MX config before caching
“Before I cache this MX record list, I want to confirm the priority ordering is correct and get a pass or advisory status on it — here are the records: [{"exchange":"primary.mail.com","priority":5},{"exchange":"backup.mail.com","priority":10},{"exchange":"tertiary.mail.com","priority":5}]”
Mail routing pre-check for SMTP agent
“My SMTP agent is about to attempt delivery and I need the MX records sorted by preference so it contacts the right server first — can you sort and rank these: [{"exchange":"smtp-a.example.org","priority":30},{"exchange":"smtp-b.example.org","priority":10},{"exchange":"smtp-c.example.org","priority":20}]”
Technical details
Endpoint
POSThttps://api.delx.ai/api/v1/x402/dns-mx-priority-sort?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a deterministic, stateless, server-side sort of DNS MX records by preference value — especially when you need a stable sort that preserves equal-priority entry order from caller-supplied data. Prefer this over client-side sorting when you need a versioned, auditable result with an explicit pass/advisory status for compliance or caching decisions. It requires no external DNS provider and operates entirely on the supplied records.
Side effects
- Malformed record objects missing priority or exchange fields may result in advisory status or sorting errors
- Arrays exceeding 256 items will be rejected per schema constraints
- Objects with more than 128 properties per record will be rejected
- Non-numeric or missing preference values may cause undefined sort behavior or advisory verdict
- Empty input array returns a trivially sorted result with pass status
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| records | array | Records supplied to DNS MX Priority Sort; used only for this bounded calculation and processed in memory without retention. |
Output
Schema · Response
{
"type": "json",
"example": {
"result": {
"count": 2,
"records": [
{
"exchange": "mx1.example.com",
"priority": 10
},
{
"exchange": "mx2.example.com",
"priority": 20
}
]
},
"schema": "delx/util-dns-mx-priority-sort/v1",
"status": "pass",
"evidence": {
"retained": false,
"input_sha256": "8b3539e1e41d77579f810b455d097216ad210c5fa90b58563e75aef928e5684a",
"external_calls": 0
},
"operation": "web_reliability:dns_mx_priority_sort"
}
}Tags
x402
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