You need to verify U.S. bank routing numbers and pull institutional details without building your own database or screen-scraper. By the end of this article, you’ll authenticate against Zyla API Hub, call the Routing Number Bank Lookup API to validate a routing number, and return bank name, address, contact, and ACH status in a way you can ship this week.
What you can build with the Routing Number Bank Lookup API
The Routing Number Bank Lookup API is a finance-focused service that resolves a U.S. routing number to detailed bank information. It returns fields including the financial institution name, ACH routing number, branch type, full address, phone, active status, and the last update date. Typical uses include onboarding validation for ACH payouts, back-office reconciliation, and pre-flight checks before initiating transfers.
On Zyla API Hub you get a single account, one API key, and a subscription + quota model for every API—no per-call microbilling. Zyla’s catalog includes more than 10,000 public APIs, all accessible with a consistent header-based authentication scheme. If you’re exploring this API for the first time, the first API offers a 7-day trial or 50 requests. There is no Free Plan; check the API page for current access options and pricing.
Getting started on Zyla API Hub
To test and integrate quickly:
- Open the Routing Number Bank Lookup API page on Zyla.
- Click Subscribe or Start Free Trial (when available) and obtain your API key.
- Call the endpoints using the Authorization header: Authorization: Bearer YOUR_API_KEY.
Zyla uses a subscription + quota model. Your requests count against your subscription tier’s quota; there is no pay-per-call. For the first API, you can use a 7-day trial or 50 requests to validate your use case before committing. Visit zylalabs.com for the full marketplace and documentation, and keep your API key secure in environment variables or your secrets manager of choice.
Authentication and request pattern
This API authenticates via a Bearer token in the Authorization header. Do not send query-string keys or origin-specific access keys. Each request must include:
- Authorization: Bearer YOUR_API_KEY
All examples below target the exact Hub endpoints hosted under https://zylalabs.com/api/.... Do not use other domains, and do not add undocumented parameters.
Endpoints you can call today
1) Get Bank Information
Method: GET
URL: https://zylalabs.com/api/331/routing-number-bank-lookup-api/266/get-bank-information
Description: Returns detailed information about a routing number, including financial institution name, ACH routing number, branch type, address, contact information, active status, and last updated date.
Required query parameters:
- routingnumber (number): e.g., 121000245
- paymentType (string): e.g., ach
Copy-pasteable 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"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"
}
}Field notes you’ll actually use:
- data.routingNumber and data.paymentType: Echo the lookup inputs you used (useful for logging and idempotency).
- data.name, data.addressFull, data.phone: Displayable bank identity and contact data for support and KYC UI.
- data.type and data.active: Useful for checks that require main office vs. branch and active status gating.
- data.lastUpdated: A timestamp you can carry to cache/refresh decisions in your application.
2) Bank Data
Method: GET
URL: https://zylalabs.com/api/331/routing-number-bank-lookup-api/1353/bank-data
Description: Retrieves detailed information for a bank by routing number and validates whether the routing number is correct. Returns bank name, address, and contact information.
Required query parameters:
- number (number): e.g., 304082876
Copy-pasteable curl:
curl -s -X GET "https://zylalabs.com/api/331/routing-number-bank-lookup-api/1353/bank-data?number=304082876" \
-H "Authorization: Bearer YOUR_API_KEY"Example response:
{"status":200,"success":true,"message":"Routing Bank 304082876 is valid","data":{"routing_number":"304082876","date_of_revision":"050712","new_routing_number":null,"bank":"CENTRIS FEDERAL CREDIT UNION","address":"11825 Q STREET","city":"OMAHA","state":"NE","zip":"68137","phone":"(402) 758-6536"}}Field notes you’ll actually use:
- success and message: Straightforward validation signal to gate the next step in your flow.
- data.routing_number: The resolved routing number for logging and audit trails.
- data.bank, data.address, data.city, data.state, data.zip, data.phone: Bank identity and contact fields for UI and compliance exports.
- data.date_of_revision and data.new_routing_number: Useful for data lineage and potential migration logic.
End-to-end example: Python integration
The snippet below hits the Get Bank Information endpoint, extracts the core fields you’ll display or store, and includes basic defensiveness around HTTP status and JSON presence. Substitute YOUR_API_KEY with your key and adjust routing numbers as needed.
import os
import sys
import urllib.parse
import requests
API_KEY = os.getenv("ZYLA_API_KEY", "YOUR_API_KEY")
BASE_URL = "https://zylalabs.com/api/331/routing-number-bank-lookup-api/266/get-bank-information"
def get_bank_info(routing_number: str, payment_type: str = "ach") -> dict:
params = {
"routingnumber": routing_number,
"paymentType": payment_type
}
headers = {
"Authorization": f"Bearer {API_KEY}"
}
url = f"{BASE_URL}?{urllib.parse.urlencode(params)}"
resp = requests.get(url, headers=headers, timeout=10)
resp.raise_for_status()
return resp.json()
def main():
rn = "121000245"
data = get_bank_info(rn, "ach")
if data.get("status") != "success":
print("Lookup did not succeed:", data)
sys.exit(1)
d = data.get("data", {})
print("Bank:", d.get("name"))
print("ACH routing:", d.get("routingNumber"))
print("Type:", d.get("type"))
print("Active:", d.get("active"))
print("Address:", d.get("addressFull"))
print("Phone:", d.get("phone"))
print("Last updated:", d.get("lastUpdated"))
if __name__ == "__main__":
main()Choosing the right endpoint for your flow
- Use Get Bank Information when you need enriched context: branch type, active status, full address decomposition (street, city, state, zip), and a lastUpdated field you can incorporate into caching logic.
- Use Bank Data when your primary goal is to validate a routing number and fetch condensed identity and contact details along with a simple success/message indicator.
Both endpoints authenticate the same way and sit under the same subscription and quota. You can mix them depending on your UI/backend needs.
Practical integration tips
- Authentication: Always send Authorization: Bearer YOUR_API_KEY. Do not place the key in the query string.
- Secrets management: Store YOUR_API_KEY in environment variables or a secrets manager, not in source control.
- Caching: Routing number data is relatively stable. Consider caching positive lookups and refreshing based on your business risk tolerance. You can use data.lastUpdated from Get Bank Information as a reference in your logs.
- Input normalization: Accept only digits for routing numbers in your UI, strip whitespace, and validate length before calling.
- Retries: Network timeouts happen. Wrap calls with short retry logic on transient failures; avoid blind retries on 4xx responses.
- Logging: Log the routing number, endpoint path, and a success/failure flag—not the full response—so you avoid leaking PII while still maintaining observability.
- Testing: Use known institutions (like the example routing numbers provided) in non-production environments to verify parsing and mapping.
Billing, quotas, and environments
This API uses a subscription + quota model on Zyla API Hub; it is not pay-per-call. For the first API you use, you get either a 7-day trial or 50 requests to evaluate. There is no Free Plan. If you need higher capacity, check the API page for the current quota options and pricing. Build your application to surface HTTP errors cleanly so you can quickly diagnose quota exhaustion in staging before impacting production.
Zyla recommends one account and API key per environment (dev, staging, prod) to simplify debugging and access control. If you must share a key across services, centralize outgoing calls through a small gateway so you can rotate keys and throttle usage predictably.
Explore more finance APIs and cross-category tools at zylalabs.com. Every listing on the marketplace uses the same authorization pattern, which streamlines multi-API integrations.
Real-world finance use cases you can ship this week
- ACH onboarding: Validate the provided routing number before storing bank account details to cut down on failed payouts.
- Payment operations: Confirm active status and phone/address for escalations when payouts fail.
- Compliance checks: Attach bank identity and address to customer records for audit trails and periodic reviews.
- Customer support tooling: Display bank name and phone next to the masked account information in your internal console.
- Back-office reconciliation: Use validation response fields to separate invalid routing numbers from downstream banking errors.
Calling the API from AI agents via MCP
If you use MCP-compatible developer tools (Claude Code, Cursor, Windsurf, etc.), you can route calls through Zyla’s MCP endpoint. Configure your client to talk to:
Pass your Zyla API key to the MCP server (apikey=YOUR_API_KEY). From there, instruct your agent to perform an HTTP GET to the Routing Number Bank Lookup API endpoints shown above with the Authorization: Bearer YOUR_API_KEY header. This lets your agent fetch routing number details without embedding raw HTTP logic in the prompt.
Troubleshooting checklist
- 401 or 403 errors: Verify the Authorization header format and that the key is valid and active.
- Unexpected payload: Confirm the endpoint path and query parameters exactly match the docs; avoid adding extra parameters.
- Quota issues: Check your subscription usage on the API page and handle quota exhaustion gracefully in your app workflow.
- Stale info concerns: Re-query periodically and log data.lastUpdated (when using Get Bank Information) for your audit trail.
Reference: Tested curl calls (copy/paste)
Get Bank Information:
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"Bank Data:
curl -s -X GET "https://zylalabs.com/api/331/routing-number-bank-lookup-api/1353/bank-data?number=304082876" \
-H "Authorization: Bearer YOUR_API_KEY"FAQ
How do I authenticate?
Send the header Authorization: Bearer YOUR_API_KEY with every request to the Hub endpoints under https://zylalabs.com/api/.... Do not include the key in the query string.
Which parameters are required for each endpoint?
Get Bank Information requires routingnumber and paymentType (use ach). Bank Data requires number. Only the documented parameters are supported.
What’s the difference between “Get Bank Information” and “Bank Data”?
Get Bank Information returns enriched fields like branch type, active status, and a lastUpdated date along with full address parts. Bank Data focuses on validation and core bank identity/contact details and provides a success/message indicator.
Is there a free tier?
There is no Free Plan. For the first API you use, you can access a 7-day trial or 50 requests. Check the API page for current access options and pricing.
Can I call this API from an AI agent?
Yes. Use the Zyla MCP endpoint and supply your API key, then have your agent issue the documented GET requests with the Authorization header. See the MCP link above.
Ready to validate routing numbers and ship your finance integration? Create your account now: Register. Then open the Routing Number Bank Lookup API, subscribe, and start calling the endpoints today.
