• Permanently free and open-source under MIT license
• Fully web-based, no download or installation required
• No account signup or login required, edit subtitles directly in the landing page
• Front-end only with zero backend, thus fully extensible and can be plugged in to a custom backend
• Minimalist UX

I talked about my design principles in the FAQ and this issue.

• Multi-track editing
• Waveform visualization
• Localization
• .srt / .vtt format support

• NextJS 15 + React 19
• shadcn + radix-ui + Tailwind CSS
• wavesurfer.js
• react-player
• Tabler icons
• Motion

git clone https://github.com/laufei/subtitle-editor.git
cd subtitle-editor
npm install
# Run the development server with Turbopack.
npm run dev
# Create a production build and type-check.
npm run build
# Serve the pre-built app.
npm run start

• app/ – Next.js 15 routing, including the localized editor in app/[locale]/ and static pages such as app/faq.
• components/ – UI building blocks, with components/ui/ holding shadcn-based primitives and domain widgets like subtitle-list.tsx.
• context/ – Global state, including the undoable subtitle store.
• hooks/ – Reusable client hooks (use-undoable-state, toast helpers).
• lib/ – Pure utilities for parsing SRT/VTT, time conversions, and locale helpers.
• messages/ – Per-locale translation catalogs consumed by next-intl.
• tests/ – Node-based unit tests plus fixtures in tests/fixtures/.
• public/ – Static assets (icons, favicons, etc.).

npm test                # Run the entire suite
npm test -- parse-vtt.test.ts  # Focus on a single file

Tests rely on Node’s built-in node:test runner and cover parsing, time conversions, and multi-track behavior. Add fixtures under tests/fixtures/ when validating new subtitle edge cases.

Locales are configured in lib/locales.ts. Add new locales by extending the locales array, providing metadata, creating a messages/<locale>.json file, and translating keys surfaced in app/[locale]/page.tsx. Middleware routes traffic based on locale prefixes while defaulting to English.

I will check issues and accept PRs regularly, but I am quite busy these days so I may not have time to develop new features. This is a community project and your contributions are always welcomed!

Released under the MIT License. See LICENSE for details.