https://2s.io/api/validate/aba
Validate a US bank ABA routing number with the Federal Reserve weighted mod-10 checksum (3-7-1) — not just a 9-digit regex. Returns {valid, routingNumber, district (routing-symbol class), reason}. Catches transposed digits in ACH/wire setup that a length check misses. Structure + checksum only; not a bank-directory existence lookup.
Start with a quote-only recipe. Payment signing stays in your project.
const response = await fetch("https://2s.io/api/validate/aba", {
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.
- Live 402 quote confirmed
GET returned a protocol-valid 402 quote (402). No payment was made.
- Origin reachable
HEAD https://2s.io/ returned 200.
- Observed in cdp-bazaar
The registry record was observed and retained with provenance.
- Observed in 402-index
Discovered through bazaar.
- Registry record checked
Registry health: healthy.
EVIDENCE
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.