Verify whether an email address is real and safe to send toGET /v1/mailcheck · x402 API by hergertsynthora

Verify whether an email address is real and safe to send to. Checks RFC syntax, live MX records, catch-all and disposable/temporary domains, role accounts (info@, admin@), free providers and common typos, returning a deliverability status and confidence score. Use it to validate and enrich contacts, clean email lists and prevent bounces. Deterministic, Ed25519-signed. 0.001 USDC on Base. First 3 calls FREE per wallet — send header 'X-WALLET: 0x<your Base address>' (no payment); then per call.

https://api.hergertsynthora.com/v1/mailcheck

What does this x402 API do?

Verify whether an email address is real and safe to send to. This is an x402-gated GET API resource from hergertsynthora. TOLL·402 confirmed a protocol-valid HTTP 402 quote on 2026-08-25. The listing records $0.05 USD-denominated per request on Base. No settled paid call has been verified.

Published price: $0.05 USD-denominated per request
Networks: Base
Latest evidence: TOLL·402 confirmed a protocol-valid HTTP 402 quote on 2026-08-25
Resource ID: e78dd313bfaad8545e1cf662

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://api.hergertsynthora.com/v1/mailcheck", {
  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

Live 402 quote confirmed2026-08-25 05:21 UTC
GET returned a protocol-valid 402 quote (402). No payment was made.
Origin reachable2026-08-25 05:20 UTC
HEAD https://api.hergertsynthora.com/ returned 200.
Observed in 402-index2026-08-25 05:19 UTC
Discovered through bazaar.
Registry record checked2026-08-25 02:19 UTC
Registry health: healthy.

What evidence supports this listing?

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

origin checkHEAD https://api.hergertsynthora.com/ → 200 on 2026-08-25

route quotelive 402 quote confirmed · GET 402 · 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 $0.05 USD-denominated per request. Raw protocol requirements remain visible below for implementation and audit use.

Baseexact50000 atomic · 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913