🔤 Unicode & HTML Entities
✅ HTML Validators & Linters
✅ HTML Validators & Linters
Use these tools to validate HTML/CSS syntax, enforce coding best practices, and catch errors that could affect rendering or accessibility.
- W3C HTML Validator (Nu) – Official validator for modern HTML standards, including HTML5.
- HTMLHint – A lightweight HTML linter to spot issues with code style, structure, and compatibility.
- FreeFormatter HTML Validator – Another quick HTML validator with tidy formatting features.
- CSS HTML Validator (by WebFX) – Flags common code mistakes and checks for SEO, accessibility, and usability issues.
⚡ Speed & Performance Testing
Diagnose load times, rendering issues, and bottlenecks with these tools. They provide metrics like Core Web Vitals, time to first byte (TTFB), and suggestions for improvement.
- Google PageSpeed Insights – Gives performance scores and actionable fixes for mobile and desktop.
- Lighthouse – Open-source tool built into Chrome for analyzing performance, SEO, accessibility, and more.
- GTmetrix – Detailed performance analysis, including waterfall charts, global test locations, and historical tracking.
- Pingdom Speed Test – Easy-to-use tool with performance grades, suggestions, and resource timing breakdowns.
- WebPageTest – Advanced speed diagnostics with filmstrip views and multi-browser/multi-location testing.
- LoadFocus – Load testing platform for measuring performance under stress and simulating traffic spikes.
🛡️ Uptime & Monitoring
Keep track of website availability, response time, and reliability with real-time monitoring and alert systems.
- Site24x7 – Full suite monitoring: uptime, defacement, SSL, server, and app monitoring with alerts.
- Pingdom Monitoring – Tracks downtime, performance changes, and alerts via SMS or email.
🔍 SEO, Indexing & Crawl Errors
Improve visibility on search engines, fix crawl/indexing errors, submit sitemaps, and analyze keyword performance.
- Google Search Console – Detects crawl issues, sitemap errors, and search visibility insights.
- Bing Webmaster Tools – Similar to Google's tool, it offers crawl diagnostics and backlink analysis for Bing.
🛠️ Dev-Focused Performance Tools (Advanced)
Deeper tools for debugging frontend issues, running audits, and simulating real-world load conditions.
- Google Lighthouse CLI – Use from terminal to integrate in CI/CD workflows or custom scripts.
- WebPageTest (Advanced Features) – Includes scripting, multiple runs, and video capture to dig into render-blocking resources.
- SEMrush Site Audit – A more holistic audit that includes performance, SEO, and crawl diagnostics for professionals.
🎨 CSS Validation & Formatting
🧹 Formatters & Beautifiers
⚙️ Image tools
- ✅ Squoosh – Google tool, simple drag-and-drop image compression in your browser.
- 🖼️ XnConvert – Free desktop tool for Windows/Mac/Linux to batch convert and compress images to WebP.
- 🌐 file-converter.io – Free desktop tool to bulk convert images (and more) directly to WebP or other formats.