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

# Sandbox

> Test against the real API, with real messages, before your application is approved.

A sandbox key (`tk_test_...`) is issued the moment onboarding completes. It calls the exact same endpoints with the exact same request and response shapes as a live key, so the code you write against it is the code you ship.

## What is different

* **Proven destinations only.** Messages go only to numbers the account has proven it owns, up to 3 per account. Add one in the dashboard with an OTP round-trip. Any other destination answers `422 sandbox_unverified_destination`.
* **A visible stamp.** Every message carries an unremovable `[TEST]` / `[تجريبي]` stamp, before any other line.
* **A lifetime cap.** 10 sends per application, charged from the same prepaid balance as live sends, so testing cannot consume the whole welcome credit. The cap answers `429 sandbox_quota_exceeded`.
* **SMS only.** WhatsApp cannot be used in the sandbox at all. The Verify API refuses it with `422 sandbox_unsupported_channel`, and the WhatsApp endpoints with `403 live_key_required`.

## A typical test

<Steps>
  <Step title="Prove a number">
    In the dashboard, add your own mobile as a sandbox destination and type the code it receives.
  </Step>

  <Step title="Run the two calls">
    Follow the [Quickstart](/quickstart) with the sandbox key. Read the code off your phone and check it.
  </Step>

  <Step title="Exercise the failure paths">
    Type a wrong code to see `invalid_code` and `attempts_remaining` count down. Call [resend](/api-reference/verify/resend-a-code) and [cancel](/api-reference/verify/cancel-a-verification). Wait out the lifetime to see `expired`.
  </Step>
</Steps>

<Note>
  Unit tests should not hit the sandbox: every send is a real SMS and counts against the cap. Record the documented responses as fixtures instead; the [API reference](/api-reference/verify/start-a-verification) carries every example body.
</Note>