Routing Number
Lookup API
Stack is the most detailed routing number data provider on the internet. Validate any routing number against our own continuously maintained database, richer than the public record, and get the bank name, address, active status, and ACH eligibility from a single API call.
Simple integration
One authenticated POST with a routing number. You get a clean, structured response with everything you need to validate and act on it.
curl https://api.stack-ft.com/utilities/banking/bank-lookup \
-H "Authorization: {api_key}" \
-d '{ "routing_number": "031302971" }'{
"status": "success",
"routing_number_valid": true,
"routing_number_info": {
"routing_number": "031302971",
"bank_name": "Customers Bank",
"is_active": "Active",
"can_ach": true,
"address": { "city": "Malvern", "state": "PA" }
}
}What you get
Instant Validation
Verify routing numbers in real-time and confirm ACH eligibility before processing transactions.
Complete Bank Details
Access comprehensive bank information including name, address, contact details, and active status.
Our Own Database
Not a stale government file. We maintain a proprietary routing number database with more data points per bank, updated continuously so your validations never go stale.
Simple Integration
Single REST endpoint with straightforward JSON response. Start validating routing numbers in minutes.
Built for fintech
Payment Processing
Validate routing numbers before initiating ACH transfers to reduce failed transactions and improve user experience.
Account Verification
Confirm bank details during account linking flows to ensure accurate payment information.
Fraud Prevention
Cross-reference routing numbers with expected bank information to detect fraudulent accounts.
User Onboarding
Auto-populate bank information during signup to streamline the onboarding process.
Simple pricing
One flat price for the API. No per-request fees, no usage tiers, no hidden costs.
Unlimited routing number validations. Sign up to your first production request in about 10 minutes.
Get StartedPrefer the whole dataset? We also license our full routing number database, down to branch locations and bank websites, delivered as a one-time copy. Request a license.
Frequently asked questions
What is a routing number API?
A routing number API lets you validate a US bank routing number and retrieve the associated bank's details (name, address, active status, and ACH eligibility) programmatically. Stack's Routing Number API returns all of this from a single REST call.
Where does Stack's routing number data come from?
Stack maintains its own proprietary routing number database rather than reselling a static government file. We continuously update bank names, statuses, and ACH eligibility, and we track more data points per institution than other providers, which is why teams rely on us as the source.
How often is the routing number database updated?
Continuously. Bank names change, institutions merge, and ACH eligibility shifts over time. We keep our database current so your validations don't silently go stale.
Can I check ACH eligibility with the API?
Yes. Every lookup includes an ACH eligibility flag so you can confirm a routing number can receive ACH transfers before you initiate a payment.
How much does the Routing Number API cost?
It's $99/month with unlimited requests. There are no per-request fees, usage tiers, or hidden costs.
Do I need a subscription to make live requests?
Yes. Your API key is authorized for live production requests while your subscription is active ($99/month, unlimited). You can start it yourself in the dashboard in a couple of minutes, no sales call required.
Can I get the entire routing number database?
Yes, by license. In addition to the API, we license our full routing number database and deliver a one-time copy as a clean structured file you can load anywhere. The dataset goes beyond the API, down to branch locations and bank websites. We retain ownership of the data; you get a license to use it. Email [email protected] with your use case.
How do I get started?
Create an account, start your subscription, and send a POST request with a routing number. Your API key is authorized for live requests while the subscription is active. It's fully self-serve: you can go from sign-up to your first production request in about 10 minutes without talking to anyone. The full reference is in our documentation.
Ready to start building?
Get your API key and start validating routing numbers in minutes.