User Agent and JS Manager icon

User Agent and JS Manager

by Alex Shand · Developer Tools
Manifest V3 Free
View in Chrome Web Store Data as of 16 Oct 2026

Advanced User-Agent switcher with per-site JavaScript and Cookie controls.

Users
34
−1 in 30 days
Rating
0.0 / 5
unchanged in 30 days
Ratings
0
0 in 30 days
Store rank
#125K
#104K among extensions
Version
1.0.3
updated 3 Dec 2025

Users

monthly, 11 months
04283Dec 2025Jun 2026Oct 2026
Latest, 16 Oct 2026: 34 usersMove the mouse over the chart for any month

Ratings count

monthly, 11 months
001Dec 2025Jun 2026Oct 2026
Latest, 16 Oct 2026: 0 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 User Agent and JS Manager

A developer tool for testing website compatibility and functionality across different environments. Instantly see how your site appears to search crawlers, social media platforms, and various browsers by switching user agents. Debug JavaScript-dependent features like form submissions and server-side rendering by toggling script execution. Configure User-Agent, JavaScript, and Cookie settings on a per-site basis with automatic persistence. Features: - Switch User-Agent to test how crawlers and different browsers view your site - Toggle JavaScript to debug form-based workflows and progressive enhancement - Block outgoing cookies for specific sites to test privacy and authentication scenarios - Configure settings individually for each website - Settings automatically apply when you revisit sites Common Uses: - Verify how search crawlers and social platforms see your pages - Test form submissions and server-side rendering without JavaScript - Debug graceful degradation in JavaScript-optional sites - Manage privacy settings for specific domains Privacy: All data is stored locally on your device. No browsing information is collected or transmitted. Permissions: - DeclarativeNetRequest: Modifies HTTP headers - ContentSettings: Controls JavaScript execution - Storage: Saves your preferences

Growth

WindowUsersChangeRatingsRating
7 days+3+9.7%00.00
30 days−1−2.9%00.00
6 months−12−26.1%00.00

Version history

1 versions recorded
1.0.33 Dec 2025

Details

Category
Developer Tools
First seen
3 Dec 2025
Size
36 KB
Languages
en
Pricing
Free
Privacy policy
github.com
Support
github.com
Extension ID
jpfikdpcedjmdadbiihkneebogfdadgb

Permissions and risk

Moderate riskimpact 3, likelihood 2
Permissions
declarativeNetRequeststoragetabscontentSettings
Site access
<all_urls>
Can read and change data on every website you visit.

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