OpenAI Codex launches a Chrome extension: can test Web Apps in the browser, pull Context across pages, and run in parallel

OpenAI May 7 (US time) announced Codex’s Chrome extension, enabling Codex coding agents to operate directly inside the Chrome browser on macOS and Windows. In its official Codex documentation, OpenAI explains that the extension allows Codex to test web apps without taking over the user’s browsing, gather context across multiple tabs, use Chrome DevTools, and run other tasks in parallel. OpenAI also announced that Codex’s weekly active users exceed 4 million, up 8x since the beginning of the year.

Things you can do inside the browser: test web apps, collect context across tabs, and use DevTools

Specific capabilities unlocked by the Chrome extension:

Test web apps—Codex can run test flows directly on the web page the user is developing

Collect context across multiple tabs—no need for manual copy-paste of tab contents

Use Chrome DevTools—Codex can directly read the page state and debug flows

Operate in parallel—without taking over the browser, users can continue doing other things

OpenAI notes that since it launched the desktop Codex app last year with Computer Use, the most common workflow happens in the browser—this Chrome extension is a concrete step to move Codex from the IDE into the browser, covering a wider range of real developer work scenarios.

User base: 4 million weekly active users for Codex, up 8x since the beginning of the year

Growth figures disclosed alongside OpenAI’s announcement:

More than 4 million weekly active users for Codex

Up 8x from the start of 2026

Install the Chrome extension via the Codex Plugins menu

This user base contrasts with the “Q1 growth 80x, compute shortage” stance Anthropic shared on 5/6—both companies saw a surge in demand for AI coding agents during Q1, and Codex and Claude Code are currently two major competing products in the developer market.

Codex Pro subscription also launched alongside: $100 per month, usage at 5x of Plus

Another change in this update is the subscription structure adjustment:

Add the Codex Pro plan at $100 per month

Usage is 5x that of ChatGPT Plus ($20 per month)

Best suited for heavy Codex developers, addressing Plus’s limits on production-grade work

Specific events to watch next: the actual adoption rate of the Chrome extension, the speed at which Codex weekly active users move from 4 million to 50 million/100 million-level users, and Anthropic’s integration strategy for Claude Code in IDEs and browsers.

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