Rewriter API

Alexandra Klepper

Thomas Steiner

Published: October 22, 2025

Explainer	Web	Extensions	Chrome Status	Intent
GitHub	Developer trial	Developer trial	View	Intent to Experiment

The Rewriter API helps you revise and restructure text. This API and the Writer API are part of the Writing Assistance APIs proposal.

These APIs can help you improve content created by users.

Use cases

Refine existing text by making it longer or shorter, or changing the tone. For example, you could:

Rewrite a short email so that it sounds more polite and formal.
Suggest edits to customer reviews to help other customers understand the feedback or remove toxicity.
Format content to meet the expectations of certain audiences.

Is your use case missing? Join the early preview program to share your feedback.

Get started

Join the Rewriter API origin trial, running in Chrome 137 to 148.

Review the hardware requirements

The following requirements exist for developers and the users who operate features using these APIs in Chrome. Other browsers may have different operating requirements.

The Language Detector and Translator APIs work in Chrome on desktop. These APIs do not work on mobile devices.

The Prompt API, Summarizer API, Writer API, Rewriter API, and Proofreader API work in Chrome when the following conditions are met:

Operating system: Windows 10 or 11; macOS 13+ (Ventura and onwards); Linux; or ChromeOS (from Platform 16389.0.0 and onwards) on Chromebook Plus devices. Chrome for Android, iOS, and ChromeOS on non-Chromebook Plus devices are not yet supported by the APIs which use foundation models.
Storage: At least 22 GB of free space on the volume that contains your Chrome profile.
Built-in models should be significantly smaller. The exact size may vary slightly with updates.
GPU or CPU: Built-in models can run with GPU or CPU.
- GPU: Strictly more than 4 GB of VRAM.
- CPU: 16 GB of RAM or more and 4 CPU cores or more.
- Note: The Prompt API with audio input requires a GPU.
Network: Unlimited data or an unmetered connection.
Key term: A metered connection is a data-limited internet connection. Wi-Fi and ethernet connections tend to be unmetered by default, while cellular connections are often metered.

Note: The network requirement is only for the initial download of the model. Subsequent use of the model does not require a network connection. No data is sent to Google or any third party when using the model.

Gemini Nano's exact size may vary as the browser updates the model. To determine the current size, visit chrome://on-device-internals.

Sign up for the origin trial

The Rewriter API is available in a joint origin trial with the Writer API. To start using these APIs:

Go to the Rewriter API origin trial.
Click Register and fill out the form. In the Web origin field, provide your origin or extension ID, chrome-extension://YOUR_EXTENSION_ID.
To submit, click Register.
Copy the token provided, and add it to every participating web page on your origin or include it in your Extension manifest.
Start using the Rewriter API.

Learn more about how to get started with origin trials.

Add support to localhost

To access the Rewriter API on localhost, use Chrome flags:

Set the chrome://flags/#rewriter-api flag to Enabled or Enabled Multilingual.
Click Relaunch or restart Chrome.

Use the Rewriter API

First, run feature detection to see if the browser supports these APIs.

if ('Rewriter' in