Online PDF Page Counter - Instant Document Inspector
Check how many pages a PDF has without uploading it (uses FileReader). Also shows file size and title if available. Simple and fast client-side tool.
UD5 Toolkit
Analyze any webpage to list all assets — CSS, JavaScript, images, fonts, media — with their sizes and types. Identify bloated resources and optimize your page load speed.
Check how many pages a PDF has without uploading it (uses FileReader). Also shows file size and title if available. Simple and fast client-side tool.
Analyze letter/symbol frequency with an interactive bar chart and heatmap. Useful for breaking simple ciphers, linguistics, and SEO keyword analysis. Local processing.
Render 1000 styled elements using inline styles vs. CSS classes and compare time. Understand CSS‑in‑JS trade‑offs.
Toggle content‑visibility: auto on long blocks and see the rendering time difference. Understand this powerful property.
Test how `content‑type: text/html` vs `content‑type: image/svg+xml` affects SVG rendering in the browser. Modern performance hint.
Select which pages to rotate left or right. Save the corrected PDF immediately. All local manipulation.
Construct HTTP Link headers for server push replacements, preload, and preconnect. Copy the header value.
List all resources loaded by the current page and their detailed timing breakdown. In‑browser waterfall.
See your current page load broken down into DNS, TLS, request, and DOM phases. Understand where time is spent.
Demonstrate how to yield heavy computation to user input using the isInputPending API. Keep UI responsive.
Calculate large Fibonacci numbers in a Web Worker. See the UI remain responsive. Copy the pattern for your app.
See your current page load broken down into DNS, TLS, request, and DOM phases. Understand where time is spent.
Adjust page characteristics (image size, server delay, layout shift) and see the simulated Core Web Vitals scores. Understand what impacts performance.
Test a regex against long strings and measure execution time. Detect catastrophic backtracking patterns. Visual warning if slow.
Enter a URL and see a waterfall of external scripts with their download size and execution time estimate. Identify performance culprits.
Paste your full CSS and HTML; automatically identify and extract the styles needed for the visible part. Reduce render‑blocking resources.
Start recording and watch for Long Tasks that block the main thread. See task duration and attribution. Improve Interaction to Next Paint.
Answer questions about your page (image size, caching, fonts) and get a tailored list of optimization tips. Manual audit helper.
Measure your browser's GPU compute power using a simple WebGPU matrix multiplication. See raw FLOPS and compare with peers. Fully client‑side.
Paste a raster image and an SVG, see the file size and rendering time. Understand when to use vector. Local.
Count total DOM nodes on the current page and show warnings if limits exceed best practices. Keep the DOM lean.
Add many complex CSS styles and measure frames per second. Isolate expensive properties. Practical performance lab.
Apply content‑visibility: auto to off‑screen sections and see the rendering cost drop. Demos for infinite scroll optimization.
Toggle contain: strict, content, paint, layout and see how it affects rendering. Understand isolation for faster pages.
Apply will‑change to any element and see its effect on compositing. Learn best practices for smooth animations.
Paste a Content‑Security‑Policy header and get a human‑readable breakdown. See potential risks and suggestions.
Use your microphone to detect the dominant frequency of ambient sounds. Visualize the spectrum. Local Web Audio.
Enter a URL and get a one‑page report of titles, description, headings, image alts, and broken links. All from browser.
Paste text and get a rough analysis of its emotional tone (happy, sad, angry, etc.) based on keyword matching. Local.
Enter a URL and get a rough client-side performance simulation: request count, DOM size, and potential speed tips. No real Lighthouse.