CSS11 min
How to Debug CSS Problems: A Practical Developer's Guide
Why your style isn't applying, what's causing the horizontal scrollbar, and how to work out which rule actually won. A methodical approach to CSS bugs.
Read article15 guides · 13 topicsGuides for people who
Guides for people who
debug things for a living
Practical write-ups on inspecting, debugging, testing and auditing websites. Written for developers, with the actual steps rather than the theory.
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SEO13 min
Technical SEO Checklist for Web Developers
The technical SEO work that belongs to developers: crawlability, indexing, canonicals, rendering, structured data and the checks to run before every release.
Read articlePerformance12 min
Website Performance Testing: A Practical Checklist for Developers
Measure the right things, in the right order: Core Web Vitals, payload weight, render-blocking assets, third-party scripts and the fixes that move the numbers.
Read articleAccessibility12 min
Web Accessibility Testing Checklist for Developers
The manual checks automated tools can't do, the ones they can, and how to test keyboard access, contrast, labels and screen reader output on a real page.
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QA & Testing13 min
The Ultimate Website QA Checklist Before Launch
Everything worth checking before a site goes live, grouped by risk: the things that lose money, the things that lose traffic, and the things people notice.
Read articleDevTools11 min
Chrome DevTools Tips That Make Web Development Faster
Shortcuts, panels and console tricks that most developers never find, organised by the task you're trying to finish.
Read articlePerformance10 min
How to Analyze Images on a Web Page
Audit every image on a page: what it weighs, whether it's oversized for its slot, which format it should be in, and whether the alt text is doing its job.
Read articleSecurity12 min
Essential Website Security Checks Every Web Developer Should Know
Security headers, cookie flags, mixed content, exposed secrets and third-party risk: the front-end checks you can run on any page in a few minutes.
Read articleTech Stack9 min
How to Find What Technologies a Website Uses
Identify the framework, CMS, CDN, analytics and hosting behind any site by reading the signals it leaves in headers, markup, globals and network requests.
Read articleStorage10 min
How to Inspect Local Storage, Session Storage and Cookies in Chrome
Find, read, edit and clear client-side storage in Chrome, understand which mechanism to use for what, and debug the state bugs they cause.
Read articleQA & Testing9 min
How to Find Broken Links, Missing Images and Page Errors
Three kinds of rot that creep into every site, how to find each one quickly, and how to stop them coming back after the next release.
Read articleSEO13 min
Technical SEO Checklist for Web Developers
The technical SEO work that belongs to developers: crawlability, indexing, canonicals, rendering, structured data and the checks to run before every release.
Read articleAccessibility12 min
Web Accessibility Testing Checklist for Developers
The manual checks automated tools can't do, the ones they can, and how to test keyboard access, contrast, labels and screen reader output on a real page.
Read articlePerformance12 min
Website Performance Testing: A Practical Checklist for Developers
Measure the right things, in the right order: Core Web Vitals, payload weight, render-blocking assets, third-party scripts and the fixes that move the numbers.
Read articleResponsive10 min
How to Test Responsive Design Across Different Screen Sizes
A working method for responsive testing: which widths matter, what device emulation gets wrong, and the checks that catch real mobile bugs.
Read articleNetwork9 min
How to View HTTP Headers in Chrome
See request and response headers for any page or asset in Chrome, plus a reference for the headers that actually change how your site behaves.
Read articleJavaScript7 min
How to Disable JavaScript on a Website in Chrome
Turn JavaScript off for one site or all sites in Chrome, using settings, DevTools or a per-site toggle, and know which method fits which job.
Read articleCSS11 min
How to Debug CSS Problems: A Practical Developer's Guide
Why your style isn't applying, what's causing the horizontal scrollbar, and how to work out which rule actually won. A methodical approach to CSS bugs.
Read articleHTML & DOM9 min
How to Inspect and Debug HTML on Any Web Page
Open the inspector, read the DOM instead of the source, and track down the markup problems that cause layout, accessibility and SEO bugs.
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