> ## 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.

> Request Sandbox credentials and set up a test environment to build and validate your Meridian Payout Origination integration before going live.

# Request a Sandbox

## Requesting Sandbox credentials

Meridian provisions Sandbox access on request. To get started, contact your Solutions Engineer and provide the following:

* Your organization's name and country of operation
* A technical point of contact with name and email
* The webhook URL you want Meridian to use for payout origination processing status events
* The sender or program identifiers Meridian should associate with your Sandbox traffic
* Any IP addresses Meridian should expect if your network policy requires allowlisting

Once Meridian receives this information, it provisions your Sandbox environment and delivers your credentials securely.

## What you'll receive

Upon provisioning, Meridian securely provides:

* **API Key** — used in the `X-Meridian-Api-Key` header on all Payout Origination API requests
* **API Secret** — used to compute the HMAC SHA-256 request signature
* **Webhook API Key and Secret** — used exclusively for authenticating inbound webhook events
* **Sandbox base URL** — for the Payout Origination API

These credentials are specific to your Sandbox environment. Meridian issues production credentials separately as part of the go-live process.

## What to validate in Sandbox

Before requesting production access, validate that your integration can:

* Base64-encode the full source payload without changing its contents
* Use the correct `{format}` path slug for the payload you submit
* Sign requests with the correct HMAC headers
* Submit a message to `POST /v1/payout-origination/{format}` successfully
* Store the returned `messageId`, then reconcile the resulting transaction in your own system
* Accept and verify webhook notifications for transaction processing status changes
* Look up transactions with `GET /v1/transactions?messageId=...` or `GET /v1/transactions/{id}`