Device Diagnostics

Device Diagnostics is an all-in-one browser-based suite for quickly testing a phone, laptop, tablet, or desktop before buying or selling it. Instead of installing separate apps, you can run screen checks, keyboard tests, speaker and microphone tests, camera preview, performance benchmarks, and sensor checks from one page. The workflow is designed for practical trust building during device handover: each tab provides clear actions, immediate visual feedback, and plain-language results. This tool is especially useful for used-device marketplaces where buyers want fast verification and sellers want transparent proof. Every test runs locally in the browser and does not transmit camera, microphone, or sensor data to external servers.

Key Features

• Unified six-tab diagnostic flow

  Run screen, keyboard, sound, camera, performance, and connectivity tests from one route without switching tools. This helps users discover additional checks naturally before finalizing a device transaction.

• Dead pixel full-screen mode

  Cycle red, green, blue, white, and black in full-screen mode to reveal stuck or dead pixels. The overlay instruction disappears on first tap and an exit button remains visible at all times.

• Audio and microphone verification

  Generate left, right, stereo, and frequency-sweep tones through Web Audio API with no external audio files. Record a short microphone sample in-browser and play it back immediately to verify capture quality.

• Live camera preview with front/rear toggle

  Use getUserMedia to display camera feed with visible resolution details and quick facing-mode switching on mobile devices. No snapshots are stored or uploaded.

• Performance and hardware quick check

  Run a JavaScript benchmark and classify rough device tier while also showing available CPU core and memory details. Battery status appears where browser support exists, with fallback messaging where it does not.

• Connectivity and sensor checks

  Test online status, estimate speed, request geolocation accuracy, read motion sensors, and trigger vibration where supported. This gives buyers and sellers a realistic view of mobile device health beyond cosmetic checks.

1. 1

   Open the diagnostics tab you need

   Start with Screen Test for display health, then move through Keyboard, Sound, Camera, Performance, and Connectivity tabs. The tool keeps the active tab in URL parameters for shareable context.

2. 2

   Run screen and touch checks first

   Use full-screen dead pixel mode and tap through each color panel to inspect pixel defects. Continue with target tapping to evaluate touch or click accuracy and center-hit precision.

3. 3

   Verify input and audio hardware

   Press physical keys to mark keyboard coverage and identify potential stuck-key behavior. Run left and right channel audio plus microphone recording playback to validate both output and input paths.

4. 4

   Confirm camera and sensor behavior

   Start camera preview and switch between front and rear lens where available, then review live resolution details. In the connectivity tab, check geolocation, motion values, and vibration response on supported devices.

5. 5

   Use benchmark and battery as quick signal

   Run the JavaScript benchmark for a rough performance tier and inspect battery status where browser APIs allow it. Combine these signals with your visual and hardware tests before making a buy/sell decision.

Explore these tools that work great alongside Device Diagnostics: