Web design and dev toolkit: device mockups, design inspector, CSS editor, SEO audit, asset extractor and screenshots.
Users
4,000
+1,000 in 30 days
Rating
4.2 / 5
+0.53 in 30 days
Ratings
5
+2 in 30 days
Store rank
#16K
#14K among extensions
Version
1.6.0
updated 14 Oct 2026
Users
monthly, 9 months
Latest, 15 Oct 2026:4,000 usersMove the mouse over the chart for any month
Ratings count
monthly, 9 months
Latest, 15 Oct 2026:5 ratingsMove the mouse over the chart for any month
The Chrome Web Store rounds user counts down to the leading digit, so the user line moves in steps. The ratings count is exact and is the better signal of real adoption.
About Codex Dev
Codex Dev – The all-in-one toolkit for web designers and developers
Test, inspect, edit and audit any website without leaving your tab. Codex Dev brings responsive testing, a visual design inspector, live CSS editing, SEO audits, asset extraction, screenshots, client feedback and AI-powered design edits together in one extension.
🖥 Responsive viewer with real device mockups
See any site on phones, tablets and desktops side by side, inside realistic device frames with notches, Dynamic Island and browser bars. Choose from a large device catalog, rotate devices, and scroll, click and type in sync across all of them. Take a full-page screenshot of any device with one click.
🎯 Design Inspector
Click any element to see its spacing, sizes, fonts, colors, contrast and accessibility details. Measure distances between elements, view the box model and grid lines, and nudge margins, padding and fonts directly on the page. A movable toolbar with quick hover tips shows how each tool works.
✨ Codex AI – design edits in plain language (bring your own key)
Select any element and describe the change: "make this section look more modern", "put these cards in a row", "add a nice hover effect". Codex AI edits the live page right away, with hover states and mobile layouts included, and you can undo every change. It sees a screenshot of your selection and follows the site's own fonts, colors and spacing. Works with your own Claude (Anthropic) or ChatGPT (OpenAI) API key. Codex AI is built for design and development work only.
✏ Visual CSS Editor
Style typography, colors, spacing and layout visually and see updates instantly. Force :hover and :active states to debug them, and export any element to CodePen with one click.
📈 SEO audit
Get a weighted SEO score with clear fixesns, canonical tags, headings and headingorder, robots and indexing, Open Graph and social cards, structured data, image alt text and sizes, lazy
loading, mixed content and link quality. ump straight to the problem. Preview yourGoogle result, review the heading outline, and check every link's HTTP status.
📌 Feedback pins for clients and teams
Pin notes to any element, mark them as a or info, and resolve them as you go. Pinsstay attached to their elements when the page scrolls or resizes. Share them as Markdown for GitHub, Jira or
Linear, or export a clean PDF report withscreen sizes.
📦 Asset extractor
Find every image, SVG, video, font and icon on the page (including inside iframes). Download a single file or
everything as a ZIP. Lottie animations ar in the panel; save them as JSON, .lottieor a standalone HTML file that plays anywhere.
📸 Screenshot capture
Capture the visible area, a full page (wiaders), a custom area or a single element,as PNG, JPEG or WEBP.
🔒 Privacy first
No account, no tracking, no analytics. Seback pins are stored only on your device.Codex AI sends your selection only when you press send, straight to the AI provider you chose with your own
key. Every other tool works entirely in y
🆓 Free and open source
Source code: https://github.com/himavamsi12/codex-dev
Built by developers, for developers.