# fittings ABA Routing Number Validator

> fittings ABA Routing Number Validator is a paid API for AI agents from fittings.sh, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-10).

Validates a US ABA routing number via its 3-7-1 check digit algorithm and decodes its Federal Reserve district and institution class.

## Facts

- Endpoint: GET https://fittings.sh/v1/aba/routing-validate?utm_source=zero.xyz
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fittings-aba-routing-number-validator-350d4391
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_aRZ_822_aeYNLiwP8p8fL

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability fittings-aba-routing-number-validator-350d4391
```

Example prompt: Can you validate the ABA routing number 021000021 and tell me whether its check digit is correct and which Federal Reserve district and institution class it belongs to?

## When to prefer this

Use this endpoint when you need to programmatically verify the structural integrity of a US ABA routing number before processing a payment, onboarding a bank account, or storing financial credentials. It is ideal for real-time validation during form submission or fraud screening, as it performs both the mathematical 3-7-1 check digit test and decodes Federal Reserve district and institution class metadata in a single lightweight call.

## Known failure modes

- Routing number not exactly 9 digits returns a validation error
- Non-numeric characters in routing number cause a parse error
- Routing number that fails check digit returns invalid status rather than an error
- Missing routingNumber query parameter returns a 400 bad request

## How this service works

Validate a US ABA routing number by its 3-7-1 check digit and decode its Federal Reserve district and institution class.

## Output

Returns whether the 9-digit ABA routing number passes the 3-7-1 check digit algorithm, along with decoded metadata including the Federal Reserve district identifier and institution class encoded within the routing number.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "routingNumber"
     ],
     "properties": {
      "routingNumber": {
       "type": "string",
       "description": "9-digit ABA routing transit number"
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fittings-aba-routing-number-validator-350d4391/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fittings.sh](https://www.zero.xyz/host/fittings.sh/llms.txt)