> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mnai.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

> Learn how to authenticate and use the Meridian Accounts API.

## Base URLs

| Environment | URL                                      | Purpose      |
| :---------- | :--------------------------------------- | :----------- |
| Sandbox     | `https://sandbox-api.va.meridianpay.com` | Testing      |
| Production  | `https://api.va.mnai.com`                | Live traffic |

Meridian provides your Sandbox environment during onboarding. Validate your integration there before using production.

## Authentication

The Meridian Accounts API supports two authentication layers:

* Partner HMAC authentication when your backend proves partner identity with `X-Meridian-*` headers and an HMAC SHA-256 signature
* JWT bearer authentication when your client or backend sends `Authorization: Bearer {token}` after a token has already been minted for a user

In a typical integration, your backend uses partner HMAC authentication to call `POST /v1/auth/token`, then later user-scoped requests use the returned JWT.

For the conceptual auth guides, see:

* [Authentication overview](/products/meridian-accounts/guides/authentication-overview)
* [Server-to-server authentication with HMAC](/products/meridian-accounts/guides/server-to-server-authentication-with-hmac)
* [Client-server authentication with JWT](/products/meridian-accounts/guides/client-server-authentication-with-jwt)