UD5 Toolkit
Whitewater Helmet Fit Test – Shake, Roll & Nod Check
Follow the interactive shake, roll, and nod tests to see if your helmet fits snugly without moving. Adjust the straps correctly.
Tag: Checker - Validator & Tester
60+ toolsWebcam Cover Fit Checker – Will It Interfere with Laptop Closure?
Many slim laptops can crack the screen if a thick webcam cover is attached. Check your model's tolerance before sticking one on.
Down Loft Restoration Checker – Tumble Dry with Tennis Balls
Photos show good loft vs flattened loft. Instructions for low‑heat drying with tennis balls to re‑fluff down after storage.
Crampon Anti‑Balling Plate Compatibility Checker
Select your crampon model to see if a factory or aftermarket anti‑bailing plate is available and how to attach it.
Camp Grill Grate Gap Safety – Prevent Food Falling Through
Enter the gap between bars and the size of your food pieces to see if they'll fall through. Use foil or a griddle if needed.
Offline Map Rectangle Viewer – Does Your Tile Set Cover This Area?
Draw a rectangle on a world map and the tool displays the approximate latitude/longitude bounds. Helps you confirm offline map downloads.
River Crossing Safety Evaluator – Depth & Speed Limits
Enter the estimated water depth and current speed to assess if it's safe to ford. Know when to turn back.
Verb Tense Consistency Highlighter – Past vs Present
Paste a paragraph and the tool highlights verbs in past, present, and future tense. Quickly spot accidental shifts that confuse readers.
Biodegradable Soap Safe Distance Checker – From Water Source
Even biodegradable soap should be used 200ft from water. Enter the river or lake location and see a circle showing where to wash.
Is Today a Public Holiday? – Global Checker
Select a country and see if today or any date is a public holiday. Plan international calls and deadlines more effectively.
Advanced Color Contrast Matrix – Test All Pairs in Palette
Paste a list of hex colors and see a grid showing the contrast ratio for every combination. Instantly identifies which pairs pass WCAG AA/AAA.
Makeup Expiration Date Checker – When to Toss Old Products
Select a makeup product type (mascara, foundation, lipstick) and enter the open date to see when it expires. Log items to get replacement reminders.
Iron Deficiency Self‑Check – Symptoms & Risk Factors
Answer questions about fatigue, pallor, craving ice, and dietary habits to see if you might be at risk for iron‑deficiency anemia. Includes food sources of iron.
Thyroid Symptom Checklist – Hyper vs Hypo Self‑Assessment
Go through a list of common hyperthyroid and hypothyroid symptoms and check which you experience. See a summary to discuss with your doctor.
Basic First Aid Guide – Symptom Checker & Action Steps
Select common injuries or symptoms (burn, cut, sprain, choking) to see immediate first aid steps. For informational use; always call 911 in an emergency.
Markdown Link Checker – Find Broken Hyperlinks in Your Docs
Paste your Markdown file content and the tool extracts all links, then checks each one for a live response. Flag dead links before publishing your docs.
Blood Donation Eligibility Checker - Online Quick Questionnaire
Answer a short questionnaire based on common deferral criteria (travel, medication, tattoos) to see if you may be eligible to donate blood. Educational only.
UK Tax Code Checker - Online Understand Your Code
Enter your UK tax code and see an explanation of what the numbers and letters mean. Simple educational reference. No data stored.
SSL Certificate Checker - Online Verify Expiry & Chain
Enter a domain and see its SSL certificate details: issuer, validity dates, and chain. Client‑side fetch.
Australia Public Holiday Checker - Online by State & Year
Select a state and year to see all public holidays. Works offline with built-in data. Plan your long weekends. Simple reference tool.
DNS Propagation Checker - Online Verify Record Status
Query a domain's DNS record against multiple public resolvers (Google, Cloudflare) and see how it propagates. Client‑side fetch.
Real‑Sample Contrast Checker - Online See Paragraph
See how a full paragraph looks with your chosen text and background colors. Not just a ratio; the real appearance.
Canonical Tag Checker - Online Rel=Canonical Inspector
Check a live URL to extract and validate its canonical link element. Ensure correct SEO configuration. Runs from your browser.
HTTP Security Header Checker - Online HSTS, CSP, X-Frame Analysis
Paste response headers string and get a security audit. Check presence and configuration of key security headers. Local analysis.
Email Spam Trigger Checker - Online Avoid Spam Filters
Paste your email subject and body. The tool highlights common spam trigger words and gives a risk score. Improve inbox placement.
Notification Permission Checker - Online Manage & Test
See your current notification permission status. Request or reset it. Test browser notification behavior.
URL Safety Checker – Scan for Malware & Phishing Threats
Enter a suspicious link and this tool performs a client‑side check against public threat intelligence feeds. See risk category before you click.
Broken Image Finder - Online Check Page for Missing Pictures
Enter a URL and get a list of all images that fail to load (404, CORS). A simple asset audit tool. Runs in your browser.
Accessible Color Contrast Grid - Online Test Combinations
Enter a palette of colors and see a grid showing whether each foreground/background pair passes AA or AAA contrast. Must for designers.
Blood Pressure Category Checker - Online AHA & ESC Guideline Tool
Interpret your blood pressure reading based on American Heart Association and European Society of Cardiology categories. Visual gauge with actionable health insights.
Bulk Color Contrast Checker - Online WCAG Validation
Paste a list of foreground/background color pairs and instantly see which pass AA/AAA. Perfect for checking entire style guides.
Local Password Breach Checker - Online k‑Anonymity
Tell if your password has appeared in data breaches without sending the full password. Uses hash prefix locally.
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.
Password Policy Checker - Online Test Against Rules
Define minimum length, uppercase, digits, special chars, and check if a password meets your custom policy. Instant feedback.
Color Contrast Checker - Online WCAG Accessibility Validator
Check the contrast ratio between foreground and background colors to ensure web accessibility compliance. Get WCAG 2.1 AA/AAA pass/fail results instantly.
Color Contrast Ratio Tester - Online WCAG AA/AAA Check
Enter foreground and background colors to instantly see the contrast ratio and pass/fail for AA and AAA. Simple and fast.
Mersenne Prime Checker - Online 2^p‑1 Validation
Check if a number of the form 2^p‑1 is a Mersenne prime. Quick Lucas‑Lehmer test simulation for small p.
URL Status Code Checker - Online Bulk HTTP Response Tool
Check HTTP status codes for multiple URLs at once. Identify broken links and redirects. All requests made via browser fetch.
HSTS Header Checker - Online Strict‑Transport‑Security
Fetch a site’s HSTS header and validate its syntax, max‑age, and subdomain flags. Ensure your site enforce HTTPS.
HTTP Redirect Path Tracer - Online SEO Chain Analyzer
Trace the full redirect path of a URL. See every hop, status code, and final destination. Detect broken chains.
HTTP Headers Checker - Online Inspect URL Response Headers
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.
SSL Cipher Suite Checker - Online Test TLS Security
Check which cipher suites a website supports and identify weak or outdated ones. Quick security audit from your browser.
Browser Extension Headers Check - Online Detect Injected Scripts
Look at HTTP headers and JavaScript objects to guess which browser extensions might be installed. For awareness.
Leap Year Checker - Online Verify February 29
Enter a year to check if it is a leap year. Shows the rule explanation and next/previous leap years. Simple reference.
IBAN Structure Checker - Online Validate Format & Country
Check if an IBAN has the correct length and structure for its country. Early validation, no bank connection.
Live Website Audit Checker - Online Quick SEO & Performance
Enter a URL and get a one‑page report of titles, description, headings, image alts, and broken links. All from browser.
Email Spam Score Checker - Online Newsletter Tester
Paste your email body and subject, and get a spam score based on common trigger words and patterns. Improve your cold outreach.
Password Strength Checker - Online Meter & Analyzer Tool
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.
Gravatar Generator & Checker - Online Email to Avatar
Preview the Gravatar image associated with any email address. Generate the correct Gravatar URL. Handy for avatar debugging.
Is It Down or Just Me - Online Website Uptime Checker
Check if a website is globally reachable or experiencing issues. Status code and latency displayed. Quick browser-side test.
Isogram Checker - Online Words Without Repeating Letters
Find out if a word is an isogram (no repeating letters). Different types: first-order, second-order. Word nerd fun.
Palindrome Checker - Online Test Words & Sentences
Check if a word or phrase is a palindrome (reads same forward and backward). Live validation and fun facts.
Favicon Checker - Online Test Any Site's Icon
Enter a URL and see its favicon at all standard sizes. Check if it's properly defined. SEO basic check.
Homophone Checker - Online Sound‑Alike Words Tool
Type a word to see all its homophones with definitions. Avoid embarrassing mistakes (their/there/they’re). Static dictionary.
Image Format MIME Checker - Online Identify True Type
Drop an image that might have wrong extension and see its real format (JPEG, PNG, WebP) based on header bytes.
PWA Install Prompt Checker - Online See beforeinstallprompt Status
Check if the browser has captured the beforeinstallprompt event. Understand why your PWA is (or isn't) installable.
Font Fallback Checker - Online See Missing Glyphs
Type any character and see how it renders in different font stacks. Detect missing glyphs and fallback behavior.
Password Pwned? Checker - Online k‑Anonymity
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.
API Status Checker - Online Test Endpoint & Response
Enter an API URL and quickly check its HTTP status code and response time. See response headers and body. Browser fetch.
npm Version Range Checker - Online SemVer & Tilde Caret
Enter a package name and version range to see all satisfying versions from the registry. Understand ^ and ~.