# Adds a testing developer assistant in Elements with Intents

## What’s new

A developer assistant is now automatically rendered in Elements while using [a sandbox](https://docs.stripe.com/testing-use-cases.md).

## Impact

This change streamlines development by adding a testing developer assistant to Elements. The assistant provides payment method autofill, customer location mocking, and integration optimizations. You can use the assistant to test your integrations and optimize your checkout flow. See [Stripe.js testing assistant](https://docs.stripe.com/sdks/stripejs-testing-assistant.md) for more information.