The Smart Timer is a professional countdown and count-up timer designed for high-stakes environments where timing precision and visibility matter: university exams, certification tests, conference talks, workshop sessions, and classroom quizzes. It runs entirely in your browser — no installation, no sign-in, no latency from a server round-trip.

The timer features a fullscreen presentation mode, customizable alert sounds (synthesized in the browser using the Web Audio API), and a remote sync feature using BroadcastChannel so a separate display screen can mirror the timer in real time.

Timing uses performance.now() combined with requestAnimationFrame for sub-millisecond accuracy, free from the drift that affects setInterval-based timers. Alert sounds are synthesized on-demand using the Web Audio API — oscillator nodes produce tones with ADSR envelopes, eliminating the need for external audio files. The remote sync feature uses BroadcastChannel to push timer state to any other tab or window open to the /timer-live URL, enabling a second monitor to display the countdown.

Exam invigilators display a large countdown timer on a projector screen for paper-based or computer-based exams. Conference speakers use it backstage to monitor their remaining presentation time. Teachers run timed classroom activities like debates or group exercises. Workshop facilitators keep breakout sessions and exercises on schedule. Podcast hosts track segment lengths during recording sessions.