First Horizon

ABA Lookup v1

ABA Lookup is a RESTful utility endpoint on First Horizon's API Banking platform that validates and resolves U.S. ABA routing transit numbers, supporting payment-instruction validation ahead of ACH and wire origination. Authorized with OAuth 2.0. Documented in HTML on the developer portal; no public OpenAPI specification is downloadable.

GitHub

Documentation

📖
Documentation
https://developers-test.firsthorizon.com/apis/v1/lookups/aba
📖
Authentication
https://developers-test.firsthorizon.com/apis/v0/oauth

Other Resources

🔗
DeveloperPortal
https://developers-test.firsthorizon.com/

Work with this as data

Every API here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for apis

7 MCP tools reach this
  • find_apisBrowse and filter every API in the catalog.
  • get_api_artifactsOne API's artifacts, grouped by type.
  • get_openapiThe primary OpenAPI for this API.
  • find_similar_apisAPIs that look like this one.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools

Call it yourself

curl for this page
This API 
curl "https://apis.io/api/v1/apis/aba-lookup-v1"
All apis 
curl "https://apis.io/api/v1/apis?limit=25"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no email required.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.

API entry from apis.yml

apis.yml Raw ↑ 
aid: first-horizon:aba-lookup-v1
name: ABA Lookup v1
description: ABA Lookup is a RESTful utility endpoint on First Horizon's API Banking platform that validates
  and resolves U.S. ABA routing transit numbers, supporting payment-instruction validation ahead of ACH
  and wire origination. Authorized with OAuth 2.0. Documented in HTML on the developer portal; no public
  OpenAPI specification is downloadable.
humanURL: https://developers-test.firsthorizon.com/apis/v1/lookups/aba
tags:
- Lookups
- Routing Numbers
- Payments
- United States
properties:
- type: Documentation
  url: https://developers-test.firsthorizon.com/apis/v1/lookups/aba
- type: Authentication
  url: https://developers-test.firsthorizon.com/apis/v0/oauth
- type: DeveloperPortal
  url: https://developers-test.firsthorizon.com/