UD5 Toolkit
Harness Fit Check for Dogs – Online Escape‑Proof Guide
Virtual checklist to see if your dog's harness is fitted properly to prevent slipping out. Photos examples.
Online Checkers & Validators
21+ toolsPet‑Safe Plants Quick Check – Online Toxic/Non‑Toxic Search
Search plant name to instantly see if it's toxic to dogs and cats. ASPCA data reference.
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.
Accessible Color Contrast Matrix – Online Paste Palette & Check
Paste hex colors, generate a contrast matrix against each other. Identify failing pairs for WCAG.
JSON Deep Diff Checker - Online Compare & Highlight Changes
Compare two JSON objects and see added, removed, or changed keys. Visual tree view with color highlighting. Handles nested structures. Local processing.
Gradient Text Contrast Checker – Online WCAG Over Background
Type text and set a gradient, then check contrast against a solid background. Ensure readability.
npm Package Name Checker – Online See If Slug Is Taken
Enter a name and query npm registry via public API to check if it's taken or scoped. Quick.
Feather Condition Visual Inspector – Online Barring & Stress Bars
Compare your bird's molted feather with reference images to identify nutritional or stress issues. Early health insight.
Catnip Reaction Visual Checklist – Online Is Your Cat Sensitive?
Observe your cat after giving catnip and mark behaviors. See if they carry the gene. Fun science.
Hex Contrast Grid – Online Test All Pair Combinations
List up to 10 colors and generate a contrast ratio matrix. See which pairs pass WCAG quickly.
Fish Disease Symptom Checker – Online Visual Diagnosis
Select visual symptoms (spots, fin rot, swelling) to narrow down possible freshwater fish diseases.
Photo Print Resolution Checker – Online DPI Maximum Size
Enter megapixels and desired DPI to see the maximum print size without upscaling. Quick quality check.
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.
Whisker Fatigue Bowl Checker – Online Measure Your Cat's Bowl
Enter bowl diameter and depth to assess whisker stress risk. Get bowl recommendations. Feline wellness.
Resting Heart Rate Checker – Online Manual Tap Count
Tap key for 15 seconds, calculates BPM. Quick resting heart rate check. Manual, no hardware.
Luggage Size Checker - Online Airline Carry-On Compliance Tool
Enter your bag dimensions and compare against major airline carry-on and checked limits. Visual pass/fail gauge. Avoid gate fees.
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.
Opened Paint Freshness Checker – Online Smell & Consistency Guide
Enter the approximate age of opened paint and answer visual/olfactory questions to see if it's still usable. Reduce waste.
Car Seat Fit Checker – Online Height/Weight vs. Seat Limits
Enter child's stats and compare to typical rear-facing, forward-facing, and booster seat requirements. Reference tool.
Bird Toy Safety Checker – Online Materials & Size Guide
Select bird species and toy type to see potential hazards and size recommendations.
Emoji Version Checker – Online See Unicode Support per OS
Enter an emoji or browse to see which Unicode version introduced it and whether older OS versions might fail.