> ## Documentation Index
> Fetch the complete documentation index at: https://docs.gx402.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Mock

> How to safely test Gx402 integrations locally and in staging using mocks and testnet.

# Testnet Mode

Testing payments safely is essential. x402 commonly offers a sandbox/test environment — use it. If x402 doesn't provide a sandbox, use local mocks and a staging account.

## Options for testing

* **x402 testnet**: if provided, configure your server to call the testbase API endpoints and testnets (Base, solana-devnet, etc.).
* **Mock provider**: run a lightweight mock x402 server that returns deterministic responses; helpful for offline UI testing.
* **In-memory store**: for quick dev, store `paymentSession` in memory instead of DB (not for multi-instance testing).

<Note>
  we don't provide any configured testnet or mock provider, so we prefer to use local testnets!
</Note>