Web Development is one of the most searched jobs in countries like India. Most of the web projects are very much concentrated in testing and quality assurance than the development. Bug fixes are the part after testing. I just came across several Chrome extensions for web developers and designers.
#1 Wappalyzer
An open-source browser extension that lets you to determine the technologies used by a website or a web application. Let it be a PHP Framework, or a CMS, or a Javascript framework or whatever. Most of the frameworks use a specific pattern or a method, by which Wappalyzer analyses and lets you know about those technologies.
[Link]
#2 Page Ruler
Perfection is all we need on a website if it needs to be appealing to a user. Both concerning functionality and interface, the whole website should possess. Page Ruler lets you measure web elements pixel wise. Page Ruler helps you to achieve pixel perfection.
[Link]
#3 ColorPick Eyedropper
This extension lets you identify color codes used in any websites that you browse. RGB, HSL and Hex code. You can pick your color just like you do with the color picker tool available in the Inspect Element pane. But this extension is handy to use.
[Link]
#4 JSONView
If you are working mostly on API stuff, then JSONView is one of the most excellent Chrome extensions for web developers. Often JSON data from the API are not in a readable format. JSONView helps in making your JSON into a tree structure so that it looks good for readability. This is an yet another open source extension. You can find the code on GitHub.
[Link]
#5 iMacros
This is the most popular Chrome extension among the web tweakers. iMacros might save you a lot of time. If you have a form where you need to fill in after each update, then iMacros works great for you. iMacros can fill in details as you once record it. So next time, you may just play it to perform all the events you made while recording.
[Link]
#6 Window Resizer
Your client loves a responsive design because he wants the user to read the contents of the website on all devices clearly. As a web designer, this extension becomes handy to switch to various screen size. You may say that this feature is already on the Inspect Element of the browser, but how handy is that to you? Window Resizer is always available on top right of the Chrome to switch screen sizes.
[Link]
#7 WhatFont
I think this is one of the most needed extension. New fonts are rising day-by-day and all new sites appeal users with a crazy and cool fonts. When are you going to use such fonts? WhatFont lets you know about the font style used in any web page.
[Link]
#8 PHP Ninja Manual
If you are a PHP developer, you may need to refer certain built-in functions to determine the parameter types or the order of it as it is one of the confusing thing in most of the programming languages. PHP Ninja Manual lets you to search for any PHP function so that you could know more details about it.
[Link]
If you have few more suggestions, let us know in comments below.