You need to verify a U.S. routing number and pull the bank’s legal name, address, phone, and status so your finance workflow can accept or reject ACH details with confidence. By the end of this guide, you’ll be able to call a production-ready endpoint that returns authoritative bank information for a given routing number and wire it into your app in under an hour.
What this API gives you
The Routing Number Bank Lookup API on Zyla API Hub returns bank metadata keyed by U.S. routing numbers. It’s built for finance workflows like ACH onboarding, payouts setup, payment rails validation, and compliance checks. You can retrieve:
- Bank name, branch type, address (street, city, state, ZIP), and phone
- ACH routing number you queried and payment type context
- Active status flag and last-updated date
- Validation that a routing number is correct before saving it
Two GET endpoints are available for lookups by routing number. Both return bank identity and contact details; one explicitly includes ACH/payment context and an “active” flag, and the other emphasizes validation messaging.
Getting started on Zyla API Hub
Open the API’s listing, subscribe, and grab your key:
- Go to the Routing Number Bank Lookup API page and click Subscribe or Start Free Trial.
- Copy your API key from the dashboard.
- Call the endpoints with Authorization: Bearer YOUR_API_KEY.
The Hub uses subscription + quota (not pay-per-call). A 7-day trial is available from the item page; check the API page for current access options and pricing. Zyla hosts more than 10,000 public APIs, so you can add other finance and payments integrations without creating new accounts or juggling multiple keys.
Start 7-day trial on Routing Number Bank Lookup API
Endpoints you can ship today
1) Get Bank Information
Method: GET
URL: https://zylalabs.com/api/331/routing-number-bank-lookup-api/266/get-bank-information
What it does: Returns detailed bank information about a routing number, including institution name, ACH routing number, branch type, address, contact information, whether the routing is active, and when it was last updated.
Required query parameters:
- routingnumber (number): e.g., 121000245
- paymentType (string): e.g., ach
Copy-paste cURL:
curl -s -X GET "https://zylalabs.com/api/331/routing-number-bank-lookup-api/266/get-bank-information?routingnumber=121000245&paymentType=ach" \
-H "Authorization: Bearer YOUR_API_KEY"
Official example response:
{
"status": "success",
"data": {
"routingNumber": "121000245",
"paymentType": "ach",
"name": "Wells Fargo Bank, Na",
"addressFull": "255 2nd Ave South, Minneapolis, MN 55479",
"street": "255 2nd Ave South",
"city": "Minneapolis",
"state": "MN",
"zip": "55479",
"type": "Main Office",
"phone": "800-245-2426",
"active": true,
"lastUpdated": "2026-07-29"
}
}
What you’ll typically use:
- data.name, data.type, data.addressFull (or street/city/state/zip)
- data.phone for customer or back-office verification
- data.active to reject inactive/retired routing numbers
- data.lastUpdated to inform cache TTLs and audit logs
2) Bank Data
Method: GET
URL: https://zylalabs.com/api/331/routing-number-bank-lookup-api/1353/bank-data
What it does: Validates a routing number and returns bank details such as name, address, city, state, ZIP, and phone.
Required query parameters:
- number (number): e.g., 304082876
Copy-paste cURL:
Example response:
What you’ll typically use:
- message to confirm validity before saving to your database
- data.bank, data.address, data.city, data.state, data.zip
- data.phone for verification or support flows
Production notes that save you time
- Authentication: Send Authorization: Bearer YOUR_API_KEY on every request.
- Idempotency: Both endpoints are GET and safe to retry.
- Caching: Bank metadata changes infrequently. Consider caching by routing number; for the Get Bank Information endpoint, you can tune TTL based on data.lastUpdated. If you cache, also store the paymentType used.
- Input validation: Accept only nine-digit U.S. routing numbers. On the Get Bank Information endpoint, include paymentType=ach exactly as shown when you need ACH-context results.
- Error handling: Program defensively around status fields and presence/absence of nested data. Log and surface the exact routing number you attempted for auditability.
- Quotas and pricing: The Hub uses subscription + quota. A 7-day trial is available from the listing. Check the API page for current access options and pricing.
Quick-start code: Python
This example calls Get Bank Information, checks the active flag, and normalizes the address for display or storage.
import requests
API_KEY = "YOUR_API_KEY"
BASE_URL = "https://zylalabs.com/api/331/routing-number-bank-lookup-api/266/get-bank-information"
params = {
"routingnumber": "121000245",
"paymentType": "ach"
}
headers = {
"Authorization": f"Bearer {API_KEY}"
}
resp = requests.get(BASE_URL, headers=headers, params=params, timeout=15)
resp.raise_for_status()
payload = resp.json()
if payload.get("status") != "success" or "data" not in payload:
raise RuntimeError(f"Lookup failed: {payload}")
data = payload["data"]
bank_record = {
"routing_number": data.get("routingNumber"),
"payment_type": data.get("paymentType"),
"name": data.get("name"),
"address": {
"street": data.get("street"),
"city": data.get("city"),
"state": data.get("state"),
"zip": data.get("zip"),
"full": data.get("addressFull"),
},
"phone": data.get("phone"),
"active": data.get("active"),
"last_updated": data.get("lastUpdated"),
}
if not bank_record["active"]:
print("Routing is inactive; block ACH setup.")
else:
print(f"OK to proceed with {bank_record['name']} at {bank_record['address']['full']}")
When to use each endpoint
- Use Get Bank Information when you need ACH context, explicit active status, and a last-updated date to drive caching or audits.
- Use Bank Data when you want a succinct validity message plus core identity fields for display or quick verification.
Common finance workflows
- Customer onboarding (ACH): Validate the routing number before saving. If data.active is false, block submission and prompt for correction.
- Payouts setup: Store data.name and data.phone with the routing so support teams can troubleshoot returns.
- Vendor management: Normalize addresses on file using addressFull/street/city/state/zip from the response.
- Fraud/compliance gates: Compare user-supplied bank name to data.name and log mismatches for review.
- Payment retries: If a debit returns due to an invalid routing, re-validate with Bank Data and show message context to the user.
Call the API from an AI agent via MCP
If you’re using an MCP-compatible client (e.g., Claude Code, Cursor, Windsurf), you can expose the Routing Number Bank Lookup API to your agent via the Zyla MCP endpoint. The agent can then execute the same GET calls you saw above with your API key, streamlining lookups during code generation or ops chats. Review the MCP docs here: MCP. The MCP endpoint accepts your API key and allows the agent to invoke Hub-listed endpoints; use the same Authorization: Bearer YOUR_API_KEY header semantics when the tool issues HTTP requests.
End-to-end testing checklist
- Happy path: A known-good routing number returns status: "success" (Get Bank Information) or success: true (Bank Data) and expected bank fields.
- Inactive path: If data.active is false, ensure your UI blocks ACH configuration and logs the event.
- Validation error: Present a clear message for non-9-digit input before sending a request.
- Timeouts: Set reasonable HTTP client timeouts (e.g., 10–20 seconds) and retry idempotent GETs once.
- Caching: Cache per routing number; consider a background refresh if lastUpdated is older than your policy threshold.
Troubleshooting notes
- 401/403 errors: Confirm the Authorization header is present and your subscription is active.
- Unexpected structure: Log the full JSON for the given routing number. Use defensive parsing around optional fields.
- Mismatch with user entry: Compare trimmed, uppercase-normalized fields; users often input colloquial bank names.
FAQ
Q: Which header is required for auth?
A: Send Authorization: Bearer YOUR_API_KEY on every request.
Q: Do I need both endpoints?
A: Not necessarily. If you need ACH context and an active flag, use Get Bank Information. If you mostly need a validity message and core identity, Bank Data is sufficient.
Q: How often does bank data change, and should I cache?
A: Bank master data changes infrequently. The Get Bank Information endpoint returns lastUpdated; use it to inform your cache TTL and audit logic.
Q: Is there a free plan?
A: There is no free plan. A 7-day trial is available from the item page; check the API page for current access options and pricing.
Q: Can I call this from AI coding tools?
A: Yes. Use Zyla’s MCP endpoint with your API key so MCP-compatible agents can invoke these GET endpoints as part of your workflow. See the MCP link above.
Ready to implement routing number validation and bank metadata in your finance flow? Subscribe and grab your key here: Start 7-day trial on Routing Number Bank Lookup API. You’ll be calling production endpoints in minutes and shipping your integration this week.