Sandbox

When building your application, you’ll want to test in sandbox with pretend money, then pilot in production using real money.

Every API and dashboard feature is available in Sandbox.

Getting a sandbox API key

If you have an Increase account, you can create sandbox API keys from the dashboard.

You can also provision a new, empty sandbox without signing up. Make an unauthenticated request to create a sandbox Group; it takes no parameters:

curl -X POST https://sandbox.increase.com/groups

The response includes a sandbox_api_key, which is only returned once, so store it:

{
  "created_at": "2026-01-31T23:59:59Z",
  "sandbox_api_key": "sk0LMB5dIbTBg0IqPgug5jZuByAsqu32"
}

Use the key as a bearer token against https://sandbox.increase.com. Sandbox keys never work in production. See auth.md for details.

Simulations

To simulate external effects you can use special Simulation APIs, which are only available in Sandbox. They can be helpful to quickly test events that might take several hours in the real world (like receiving a wire or ACH). They’re also great for testing edge cases, like returned ACHs and card refunds.

If you have a sandbox Event Subscription configured, calling these APIs will also result in the appropriate webhooks being sent to your endpoint.