Device & Hardware Testing
Hardware problems rarely announce themselves. A pixel dies quietly, a mouse switch starts registering double-clicks, a monitor silently runs at half its refresh rate — and you live with the symptom for months because there's no error message pointing at the cause.
These guides show you how to check each part of a device methodically, whether you're diagnosing a problem, verifying a repair, or inspecting a second-hand purchase before money changes hands. Every test linked here runs in your browser: nothing to install, and nothing you capture — video, audio, or readings — ever leaves your device.
Guides in this topic
How to Test a Used Phone Before Buying: A 10-Minute Checklist
A practical checklist for inspecting a second-hand phone on the spot — dead pixels, touch dead zones, sensors, battery health, cameras, and speakers — using free browser tests.
Why Your Mouse Double-Clicks on Its Own (and How to Fix It)
What switch chattering is, why worn mice register phantom double-clicks and keyboards double-type letters, how to confirm it with a browser test, and your repair options.
Monitor Refresh Rate Explained: 60Hz vs 120Hz vs 144Hz
What refresh rate actually is, whether you can see the difference past 60Hz, why a new 144Hz monitor often runs at 60 by mistake, and how to verify yours is set correctly.
How to Test Your Mic, Camera, and Speakers Before a Video Call
A two-minute pre-call routine — check that your microphone picks up sound, your webcam looks right, your speakers play both channels, and your connection is stable.
Other guide topics
Data Formats & Encoding
Guides to the formats and encodings that move data around the web — JSON, XML, YAML, CSV, Base64, URL encoding, and character sets.
Text & Writing
Guides for working with text — case conventions, word counts and readability, URL slugs, cleaning up messy text, and character encoding.
Images & Media
Guides to working with images for the web — compression, choosing formats, resizing and cropping, and the metadata hidden inside photos.
PDF & Documents
Guides to editing and organizing PDF files — merging, splitting, compressing, and converting — all without uploading your documents.
Web & Developer
Guides to the building blocks of web development — JWTs, timestamps, HTTP status codes, regular expressions, and color formats.
Security & Privacy
Practical guides to protecting your accounts and data — strong passwords, two-factor authentication, and keeping private information out of the files you share.