Robots.txt Validator - Online Check Syntax & Rules
Paste a robots.txt file and validate its syntax. See if a specific user‑agent can access a path. Essential for webmasters.
UD5 Toolkit
Simulate browser redirect behaviour or test live URLs (with CORS support) to see exactly how browsers follow each redirect step.
Access-Control-* headers. Use our Simulator or a server‑side tool for arbitrary URLs.Paste a robots.txt file and validate its syntax. See if a specific user‑agent can access a path. Essential for webmasters.
Look at HTTP headers and JavaScript objects to guess which browser extensions might be installed. For awareness.
Simulate a traceroute by entering a destination IP. Learn about AS paths and latency. Does not send real packets; educational visualisation.
Build an iframe with different sandbox flags and see live which features are blocked. For secure embedding.
Test required, pattern, minlength etc. See validity states and custom error messages. Learn browser‑native validation.
Paste response headers string and get a security audit. Check presence and configuration of key security headers. Local analysis.
Paste a user agent string to get a human-readable breakdown of browser, operating system, and device. See your own current agent info automatically.
Paste two JSON objects and find the structural differences with side‑by‑side highlighted output. Indispensable for API debugging.
Test if a script or style will be allowed by a given CSP. Compute hash/nonce. Strengthen your site’s defense against XSS. Local.
Compare two text blocks and highlight differences line by line. Ideal for code review and document revisions. All diffs computed locally for privacy.
Browse Unicode by block: Latin, Cyrillic, CJK, Emoticons. See characters and copy with a click. Full reference.
Parse a URL's query string into a key-value table, or build a query string from parameters. Perfect for API testing and web development.
See your monitor's color depth and pixel depth. Detect if HDR or wide gamut is available using media queries.
Paste a JSON Web Token and decode its header and payload. Verify signature if you provide the secret. Fully local.
Paste an HTML snippet and see how a screen reader might interpret it. Highlights missing alt texts and ARIA misuses. Educational.
Paste a potential XSS vector and see if it executes in a sandboxed iframe. For security researchers and education.
Design a clean, professional email signature with your photo, links, and disclaimers. Copy the HTML to use in Gmail/Outlook.
Design borders with linear or conic gradients. Supports border‑image and background‑clip methods. Copy optimized CSS.
Draw walls on a grid and watch A*, Dijkstra, or BFS find the shortest path. Interactive animation. Learn graph traversal.
Create a polished HTML email signature with your photo, links, and company details. Live preview and copy HTML to clipboard. Works with Gmail, Outlook, Apple Mail.
Paste a website's HTML and see which text is only visible to screen readers (e.g., .sr‑only). Preview the accessible layer.
Graph a cubic‑bezier or steps easing function and see a bouncing ball animation using it. Copy the CSS timing‑function.
Compose messages with bold, italic, links, and code. See the raw HTML or Markdown for your Telegram bot API calls.
Type your name and create a stylized ASCII text banner for email signatures or forum posts. Choose a font style.
Create custom traceable handwriting worksheets with name or sentence. Print in dotted font. Great for teachers and parents.
Enter HTML with aria-labels and see what a screen reader would announce. Simulates common patterns. Local educational tool.
Draw pixel art with a grid, color palette, and eraser. Export as PNG. Perfect for game developers and hobbyists.
Paste media queries and see a visual indicator of which rules apply at current viewport size.
Quickly test SQL JOIN syntax (INNER, LEFT, RIGHT, FULL) with a sample database schema. Check logic and see conceptual result set without a real DB. Local only.
Track up to 5 habits with a visual chain. Tap to mark day as done, see longest streaks. Data saved in your browser. Inspired by 'Don't break the chain' method.