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Welcome to the ACH Technical Guides. This documentation serves as a centralized reference for understanding and integrating with our API. These guides are designed to provide:
  • A high-level overview of each API endpoint
  • Request and response modeling to help guide implementation
  • Best practices and common patterns for working with our platform
These guides are intended for developers, engineers, and technical stakeholders working with the our ACH API.

Goals of This Documentation

  • Clarity – Reduce guesswork by providing exact input/output examples
  • Consistency – Encourage standardized usage of endpoints across teams
  • Speed – Enable quicker implementation and onboarding for developers

Testing

To test in GrailPay’s sandbox environment you will need to connect to our Sandbox API Environment. You can reach our sandbox environment at: https://api-sandbox.grailpay.com

Testing Bank Accounts

When creating people, businesses, or merchants in the sandbox, you can simulate bank accounts using:
  • A random 12-digit account number
  • One of the following test routing numbers:
    • 226078036
    • 221979363
This setup allows you to test your full integration flow — including onboarding, transactions, and ACH processing — without interacting with real financial institutions. interacting with real financial institutions.

Testing Social Security Numbers (SSNs)

When testing in the Sandbox environment, Social Security Numbers (SSNs) must follow specific formatting rules to be considered valid. The SSN:
  • Cannot begin with "000" or any value in the range "900–999"
  • Cannot have "00" as the middle two digits
  • Cannot end in "0000"
Any other valid 9-digit SSN format outside of these constraints is acceptable for testing purposes.
These guides are a work in progress. If you don’t see what you need, please reach out to our support team for assistance.
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