Device-Test is a free, privacy-first browser utility that checks microphones, cameras, speakers, screen sharing, displays, keyboards, gamepads, sensors, and network quality in one place. It uses native Web APIs and performs media processing locally, so captured audio, video, and screen content is not uploaded to a server. The account-free workflow helps remote workers validate equipment before meetings, support teams troubleshoot browser permission and hardware issues, and QA engineers reproduce device compatibility problems across browsers and operating systems. Device-Test includes live audio waveforms and volume metering, camera previews with device selection, screen-sharing capability checks, display diagnostics, input testing, and guided troubleshooting. It works directly in modern browsers with no installation, signup, or credit card.