GETinvalid 402 · origin reachablediscovery only

SYNTHORA MailCheckGET /service · x402 API by SYNTHORA

Verify whether an email address is real and safe to send to: RFC syntax, live MX, catch-all, role-account, disposable detection, normalization. Ed25519-signed.

https://mailcheck.hergertsynthora.com/service

What does this x402 API do?

SYNTHORA MailCheck. This is an x402-gated GET API resource from SYNTHORA. TOLL·402 records origin reachable evidence as of 2026-08-25. The listing records $0.001 USD-denominated per request on Base. No settled paid call has been verified.

Published price: $0.001 USD-denominated per request
Networks: Base
Latest evidence: TOLL·402 records origin reachable evidence as of 2026-08-25
Resource ID: ee0f510cc603c517f5cab33e

USE THIS RESOURCE

Start with a quote-only recipe. Payment signing stays in your project.

CODE

AI CODING TOOLS

quote-check.ts

const response = await fetch("https://mailcheck.hergertsynthora.com/service", {
  method: "GET",
});

console.log(response.status);
console.log(Object.fromEntries(response.headers));
console.log((await response.text()).slice(0, 1000));

// A valid 402 is a quote, not a completed paid call.

This sends no payment. Inspect the 402 response before adding a wallet-enabled client.

JSON ↗developer docs →

STATUS HISTORY

JSON RSS

Exact route checked2026-08-25 05:21 UTC
http 402 invalid · accept-0:resource-mismatch
Origin reachable2026-08-25 05:20 UTC
HEAD https://mailcheck.hergertsynthora.com/ returned 404.
Observed in 402-index2026-08-25 05:19 UTC
Discovered through self-registered.
Registry record checked2026-08-25 01:06 UTC
Registry health: healthy.

What evidence supports this listing?

402-indexobserved 2026-08-25 · open source record ↗

origin checkHEAD https://mailcheck.hergertsynthora.com/ → 404 on 2026-08-25

route quoteHTTP 402 returned, but its payment requirements failed protocol validation · 2026-08-25

Each record has an exact-route quote outcome. Unresolved templates and potentially mutating methods are labeled instead of being invoked without provider-specific test input. A quote is still separate from a settled paid call. Read the discovery and verification methodology →

Which networks and payment options does it accept?

The normalized listing price is $0.001 USD-denominated per request. Raw protocol requirements remain visible below for implementation and audit use.

The registry did not expose full payment options for this record.