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In Newly v2, at app.newly.app and in Newly for Mac, every Remote chat has two cloud simulators. Remote chats run in the cloud. Your simulator is for trying the app yourself. The agent’s simulator is the one the agent uses to test its work. Both run on devices Newly hosts and stream into the preview pane. For an overview of the pane and the Web view, see Previewing your app. The devices are fixed: “iPhone 17 Pro - iOS 26” for iOS and “Pixel 8 - Android” for Android. You can’t pick another model or OS version.

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Your simulator

1

Open the preview pane

Choose iOS or Android in the Simulator pill.
2

Press Start my simulator

A checklist shows progress: “Preparing your app”, “Leasing a simulator”, “Starting Metro and bundling” and “Installing your app”. Press Cancel if you change your mind.
3

Use your app

When the device is ready, its screen appears in the pane. Click and type on it as you would tap and type on a phone.
Pressing Preview in the chat header does the first two steps for you. In the web app, you may first see a “Prepare your simulator” card. Press Prepare simulator to continue.

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What the card says

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The agent’s simulator

The agent’s simulator is the device the agent drives while it tests your app.
  1. Choose iOS or Android in the Agent pill.
  2. Press Open agent simulator.
  3. Watch the device while the agent works.
While the device gets ready, the card shows steps such as “Requesting simulator…”, “Building iOS app…” or “Building Android app…”, “Leasing simulator…” and “Installing app…”. When the agent saves a walkthrough recording of what it tested, Live and Walkthrough tabs appear above the device. Live shows the device now. Walkthrough plays the recording. Press Open replay to open it in a new tab. If you see “Agent simulator ended”, press Open again for a fresh device. If you see “Couldn’t open the simulator”, press Try again.

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Controls

Hover over the right edge of a running simulator to show its control rail:
  • Reload the app
  • Save screenshot to Downloads
  • Home
  • Back (Android)
  • App switcher (iOS) or Overview (Android)
  • Rotate
  • Start webcam injection, which feeds your computer’s webcam to the device camera
  • Copy from Simulator Clipboard and Send to Simulator Clipboard
  • Upload media (web app only), which adds a JPEG, PNG or MP4 file to the device’s photo gallery

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When the code changes

  • JavaScript changes usually appear on your simulator within seconds. Nothing needs reinstalling.
  • Native changes, such as a new native package, need a new build. When the build is ready you see “The agent changed native code. Update to install the new build.” Press Update.
If your simulator failed or went idle while an update was waiting, the button reads Update and try again or Update and resume.

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Idle simulators

Your simulator is released after about 10 minutes without activity. It’s also released when the chat parks. Your code and the chat aren’t affected. Press Resume to start a fresh device with the newest completed build. To learn when a chat parks, see Parked chats and limits.

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Android builds

Android builds wait for a free build worker. The card shows “Waiting for an available Android build worker. Your build will start automatically.” You don’t need to do anything. If a build waits or runs for too long, it fails and the card tells you how to retry.

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Logs and debug info

On Mac: in Remote chats, App Logs sits at the bottom-right corner of the preview pane. The Metro tab (for example Metro · iOS) shows the app’s JavaScript output. The Native Build tab shows build progress and output. In the web app and on Mac: when a chat hits a problem, the failure card in the chat has a Copy debug info button. Paste the result into your message when you contact support.

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Credits

The cloud simulators don’t draw down credits. The agent’s work in the chat does. See How credits work.

Previewing your app

The preview pane, the Preview button and the Web view.

Native builds and packages

What triggers a rebuild and what’s preinstalled.

Testing on a real phone

Getting your app onto an iPhone.

Messages explained

What preview and build messages mean.