Cadenza

Library

Words that light up as they're spoken.

Cadenza works out when each word of a text is said, with no recording needed, and exports captions any video player reads. Press play and watch the words light up. Notice how long $4.2M stays lit: Cadenza times it as "four point two million dollars". Then edit the text below and play it again.

0.0s / 0.0s

silent

▸ Your text — type or paste anything; it re-times as you type

Five things to try

▸ A better voice — optional; without it, your browser's own voice reads

Your key is stored only in this browser (localStorage), same as the Playground — it never leaves your device. Get one at openrouter.ai/keys. Without a key this page uses your device’s built-in browser voice.

▸ The caption file — standard WebVTT, with a timestamp on every word

This page runs the real library in your browser. Learn how Cadenza works, and how to use it →