---
title: "OAuth Validator Modules"
id: oauth-validators
pg_version: "20devel"
---

<a id="oauth-validators"></a>

# OAuth Validator Modules

## Table of Contents

- [50.1. Safely Designing a Validator Module](oauth-validator-design.md)
  - [50.1.1. Validator Responsibilities](oauth-validator-design.md#oauth-validator-design-responsibilities)
  - [50.1.2. General Coding Guidelines](oauth-validator-design.md#oauth-validator-design-guidelines)
  - [50.1.3. Authorizing Users (Usermap Delegation)](oauth-validator-design.md#oauth-validator-design-usermap-delegation)
- [50.2. Initialization Functions](oauth-validator-init.md)
- [50.3. OAuth Validator Callbacks](oauth-validator-callbacks.md)
  - [50.3.1. Startup Callback](oauth-validator-callbacks.md#oauth-validator-callback-startup)
  - [50.3.2. Validate Callback](oauth-validator-callbacks.md#oauth-validator-callback-validate)
  - [50.3.3. Shutdown Callback](oauth-validator-callbacks.md#oauth-validator-callback-shutdown)
- [50.4. Custom HBA Options](oauth-validator-hba.md)
  - [50.4.1. Options API](oauth-validator-hba.md#oauth-validator-hba-api)
  - [50.4.2. Limitations](oauth-validator-hba.md#oauth-validator-hba-limitations)
  - [50.4.3. Example Usage](oauth-validator-hba.md#oauth-validator-hba-example-usage)

PostgreSQL provides infrastructure for creating custom modules to perform server-side validation of OAuth bearer tokens. Because OAuth implementations vary so wildly, and bearer token validation is heavily dependent on the issuing party, the server cannot check the token itself; validator modules provide the integration layer between the server and the OAuth provider in use. 

OAuth validator modules must at least consist of an initialization function (see [Section 50.2](oauth-validator-init.md)) and the required callback for performing validation (see [Section 50.3.2](oauth-validator-callbacks.md#oauth-validator-callback-validate)). 


> [!WARNING]
> Since a misbehaving validator might let unauthorized users into the database, correct implementation is crucial for server safety. See [Section 50.1](oauth-validator-design.md) for design considerations.