Routing Number Lookup

Overview

A routing number validation API for ACH payment forms. Pass any nine-digit US routing number to run a routing number check against its mod-10 checksum and look up the bank name in a routing number database updated daily. The service categorizes the prefix as primary, thrift, electronic, or government, and identifies the Federal Reserve district. Paid plans add the registered street address, city and postal codes, office codes, and updated routing numbers for merged institutions.

Live Test Routing Number Lookup API →

Endpoint

One host, one path per API. The block below shows this call in four languages; every one of them is the same HTTP request. Making requests covers the timeouts, retries and parameter rules that apply to all of them. The SDKs wrap the same call in a typed client.

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curl "https://api.apiverve.com/v1/routinglookup?routing=121000358" \
  -H "x-api-key: your_api_key_here"

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const res = await fetch('https://api.apiverve.com/v1/routinglookup?routing=121000358', {
  headers: { 'x-api-key': 'your_api_key_here' },
});

if (!res.ok) throw new Error(`${res.status} ${await res.text()}`);

const { data } = await res.json();
console.log(data);

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import requests

res = requests.get(
    "https://api.apiverve.com/v1/routinglookup?routing=121000358",
    headers={"x-api-key": "your_api_key_here"},
    timeout=15,
)
res.raise_for_status()

print(res.json()["data"])

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package main

import (
	"fmt"
	"io"
	"net/http"
)

func main() {
	req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/routinglookup?routing=121000358", nil)
	req.Header.Set("x-api-key", "your_api_key_here")

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()

	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}

Replace your_api_key_here with the key from your dashboard. When the inputs arrive as a list rather than one at a time, batch requests run up to 200 of them through this same API in a single call.

Authentication

Send your key in the x-api-key header. That is the only auth step — there is no token exchange and no per-endpoint scope to configure. Authentication covers creating, rotating and revoking keys.

Parameters

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them.

Response

Every API returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape. Response format covers the envelope, the other output formats and how premium fields are withheld.

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{
  "status": "ok",
  "error": null,
  "data": {
    "routing_number": "121000358",
    "office_code": "O",
    "record_type_code": "1",
    "new_routing_number": "000000000",
    "bank": "BANK OF AMERICA, N.A.",
    "address": "8001 VILLA PARK DRIVE",
    "city": "HENRICO",
    "state": "VA",
    "zip": "23228",
    "zip_extension": "0000",
    "country": "US",
    "federal_reserve_district": "San Francisco",
    "federal_reserve_states": [
      "AK",
      "AS",
      "AZ",
      "CA",
      "GU",
      "HI",
      "ID",
      "MP",
      "NV",
      "OR",
      "UT",
      "WA"
    ],
    "address_in_district": false,
    "states_served": [
      "CA"
    ],
    "routing_type": "primary",
    "is_valid_checksum": true,
    "routing_analysis": {
      "is_head_office": true,
      "is_branch": false,
      "is_federal_reserve_bank": false,
      "is_active": true,
      "replaced_by": null
    }
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change. Error handling covers the full status list and which of them are worth retrying.

Use cases

Direct Deposit Setup

When onboarding new hires, payroll systems validate the entered routing number and auto-fill the financial institution name before issuing paychecks.

ACH Transfer Verification

To prevent transfer rejections, payment processors test mod-10 checksums and confirm the receiving bank matches customer paperwork before scheduling debits.

Accounting Vendor Onboarding

Procurement teams verify supplier banking details during vendor registration to catch typos and detect obsolete routing numbers before sending disbursements.

Merchant Account Enrollment

Flag invalid or non-standard bank routing numbers during merchant signup workflows to block fraudulent accounts and reduce settlement errors.

Other ways to use Routing Number Lookup

Set up Routing Number Lookup on APIVerve, or reach the same source a different way. Your APIVerve account and credits work on all of them — one key, one balance.

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