Localhost Warning icon

Localhost Warning

by Ondřej Chlumecký · Developer Tools
Manifest V3 Free
View in Chrome Web Store Data as of 17 Oct 2026

Displays a warning banner on local and development pages.

Users
12
−2 in 30 days
Rating
5.0 / 5
unchanged in 30 days
Ratings
1
0 in 30 days
Store rank
#181K
#151K among extensions
Version
2.0
updated 27 Mar 2025

Users

monthly, 2 years
0815Mar 2025Jan 2026Oct 2026
Latest, 17 Oct 2026: 12 usersMove the mouse over the chart for any month

Ratings count

monthly, 2 years
001Mar 2025Jan 2026Oct 2026
Latest, 17 Oct 2026: 1 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 Localhost Warning

This extension helps developers easily recognize when they are working in a local or development environment by displaying a clear warning banner at the top of the page. 🚀 Features: ✅ Detects localhost, 127.0.0.1, .docker, and dev. domains. ✅ Displays a red warning banner with “This is a local or development page!” message. ✅ Prevents accidental modifications or actions in non-production environments. ✅ Works automatically on all web pages without additional setup. Perfect for developers, testers, and teams working with local or staging environments! 🔧 How to use: 1. Install the extension. 2. Open any local or development site (e.g., http://localhost, http://xxxx.docker, https://dev.xxxx). 3. See the warning banner at the top of the page. ⚠️ Note: This extension does not modify site functionality—it only adds a visual indicator to prevent mistakes.

Growth

WindowUsersChangeRatingsRating
7 days+1+9.1%00.00
30 days−2−14.3%00.00
6 months−1−7.7%00.00
1 year−2−14.3%00.00

Version history

2 versions recorded
2.027 Mar 2025
1.023 Mar 2025

Details

Category
Developer Tools
First seen
23 Mar 2025
Size
121 KB
Languages
en
Pricing
Free
Extension ID
nkljlhcbfllhilmhodkaihodbnhlfhin

Permissions and risk

Low riskimpact 2, likelihood 1
Permissions
activeTabstorage

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