---
title: Test mode
description: Build and test your integration without spending money.
sidebar:
  order: 3
---

Test keys (`tc_test_…`) behave like live keys, with three differences:

1. **They spend a simulated balance.** It starts at $1,000. Reset it on the developer page at any time.
2. **Nothing is charged or retired.** No credits are bought and no certificate is issued, so `certificate_url` stays `null`.
3. **Offsets are placed after a few seconds.** A test offset is `processing` for about 5 seconds, then `placed`.

Everything else is the same: your rate, validation, idempotency, rate limits, and errors such as `402 insufficient_balance` once the simulated balance runs out.

Responses for test keys say `"livemode": false`, and test offsets never appear for live keys.

:::tip
Run your integration tests against a test key, and switch to a live key only in production.
:::