Basic Grammar Checker - Online Free Writing Assistant
Identify common grammar mistakes (subject-verb agreement, tense, articles) with simple rule-based analysis. Explanations provided. Not AI, purely rule-based and local.
UD5 Toolkit
Check if a word or phrase is an isogram — no repeating letters. Start typing or click an example.
Identify common grammar mistakes (subject-verb agreement, tense, articles) with simple rule-based analysis. Explanations provided. Not AI, purely rule-based and local.
Check if the browser has captured the beforeinstallprompt event. Understand why your PWA is (or isn't) installable.
Check if a password appears in the Have I Been Pwned database using k‑Anonymity. Only the first 5 characters of the hash are sent.
Enter foreground and background colors to instantly see the contrast ratio and pass/fail for AA and AAA. Simple and fast.
Check which cipher suites a website supports and identify weak or outdated ones. Quick security audit from your browser.
Fetch a site’s HSTS header and validate its syntax, max‑age, and subdomain flags. Ensure your site enforce HTTPS.
Generate short, URL‑safe, unique string IDs with customizable alphabet and length. Smaller than UUID. Local only.
Create ULIDs that are time‑based, URL‑safe, and sortable. Alternative to UUID for modern applications. Copy or download a list.
Enter an API URL and quickly check its HTTP status code and response time. See response headers and body. Browser fetch.
Type any character and see how it renders in different font stacks. Detect missing glyphs and fallback behavior.
Enter a URL and get a one‑page report of titles, description, headings, image alts, and broken links. All from browser.
Look at HTTP headers and JavaScript objects to guess which browser extensions might be installed. For awareness.
Enter a package name and version range to see all satisfying versions from the registry. Understand ^ and ~.
Define minimum length, uppercase, digits, special chars, and check if a password meets your custom policy. Instant feedback.
Check if an IBAN has the correct length and structure for its country. Early validation, no bank connection.
Drop an image that might have wrong extension and see its real format (JPEG, PNG, WebP) based on header bytes.
Enter a URL and see its favicon at all standard sizes. Check if it's properly defined. SEO basic check.
Paste text to see a live letter frequency bar chart. Helps break substitution ciphers. All local analysis.
Check if a number of the form 2^p‑1 is a Mersenne prime. Quick Lucas‑Lehmer test simulation for small p.
Trace the full redirect path of a URL. See every hop, status code, and final destination. Detect broken chains.
Paste your email body and subject, and get a spam score based on common trigger words and patterns. Improve your cold outreach.
Type a word to see all its homophones with definitions. Avoid embarrassing mistakes (their/there/they’re). Static dictionary.
Enter a year to check if it is a leap year. Shows the rule explanation and next/previous leap years. Simple reference.
Check if a word or phrase is a palindrome (reads same forward and backward). Live validation and fun facts.
Check HTTP status codes for multiple URLs at once. Identify broken links and redirects. All requests made via browser fetch.
Preview the Gravatar image associated with any email address. Generate the correct Gravatar URL. Handy for avatar debugging.
Check if a website is globally reachable or experiencing issues. Status code and latency displayed. Quick browser-side test.
Enter a URL and see the full HTTP response headers returned by the server. Detect redirects and server type. Useful for SEO and web debugging.
Evaluate the strength of your passwords with a visual meter and detailed feedback. Check for length, complexity, and breached passwords. All analysis is client-side.
Check the contrast ratio between foreground and background colors to ensure web accessibility compliance. Get WCAG 2.1 AA/AAA pass/fail results instantly.