Pesticide

by London App Brewery · Developer Tools

Manifest V3 Free

View in Chrome Web Store Data as of 15 Oct 2026

A CSS debugging tool that inserts outlines onto all elements to help with debugging layout issues

Users

200K

0 in 30 days

Rating

3.4 / 5

−0.62 in 30 days

Ratings

145

−1 in 30 days

Store rank

#1,321

#1,191 among extensions

Version

2.0.0

updated 10 Mar 2025

Users

monthly, 3 years

Latest, 15 Oct 2026: 200,000 usersMove the mouse over the chart for any month

Ratings count

monthly, 3 years

Latest, 15 Oct 2026: 145 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 Pesticide

This extension inserts the Pesticide CSS into the current page, outlining each element to better see placement on the page. This is a forked copy of Pesticide created originally by Adam Morse: https://github.com/mrmrs/pesticide This copy of Pesticide is created for students on the Complete Web Development Bootcamp by Dr. Angela Yu. https://www.udemy.com/course/the-complete-web-development-bootcamp/