A modern, powerful Chrome Extension to inject, customize, and synchronize SRT & WebVTT subtitles directly into YouTube videos.
🚀 Installation • ✨ Key Features • ⌨️ Shortcuts • 📖 Usage Guide
Subly is a lightweight, high-performance browser extension for Google Chrome and Chromium browsers (Edge, Brave, Opera, Vivaldi), allowing you to effortlessly inject custom subtitle files (.srt, .vtt, .txt) directly into any YouTube video with zero delay, clean native styling, and real-time synchronization.
Whether you are studying foreign languages, watching films or anime without official captions, or following lecture videos, Subly 2.0 provides the cleanest and most customizable viewing experience.
- 🎯 Direct Drag & Drop onto Player:
- Simply drag any
.srtor.vttfile from your desktop and drop it directly onto the YouTube video player. Subtitles load and start playing immediately!
- Simply drag any
- ⏱️ Real-time Subtitle Sync:
- Adjust timing offset (+/- 0.1s, 0.2s, 0.5s, 1.0s) directly in the Popup or via quick keyboard shortcuts (
Alt + [,Alt + ],Alt + \).
- Adjust timing offset (+/- 0.1s, 0.2s, 0.5s, 1.0s) directly in the Popup or via quick keyboard shortcuts (
- 📁 Dual SRT & WebVTT Support:
- Automatically handles decimal commas
,and periods., optional hours, removes non-cue tags, handles UTF-8 BOM, and supports all international character sets.
- Automatically handles decimal commas
- 🎨 Live Subtitle Preview:
- A real-time preview box in the Styling tab reflects font size, font family, text color, background opacity, and text shadow changes instantly without having to reopen the popup.
- 🔍 Dialogue Search & Timestamp Jump:
- Search any word or dialogue line across the entire subtitle file. Click any line to immediately jump YouTube's player to that exact timestamp.
- 🔔 On-Screen HUD Toasts:
- Sleek, native YouTube-styled toast pill displays instant visual feedback when changing font size, offset, or toggling captions.
- 🛡️ Intelligent Ad Suppression:
- Automatically suppresses custom subtitles during YouTube ads and seamlessly resumes them when the main video continues.
- 💾 Smart Per-Video Persistence:
- Remembers loaded subtitle files and sync offsets for recently watched videos and restores them automatically.
- ✋ Draggable Subtitles:
- Drag subtitles anywhere on screen with your mouse to avoid covering burned-in video text. Double-click to reset back to default position.
| Shortcut | Function |
|---|---|
| Alt + T | Toggle Subly Subtitles On / Off |
| Alt + [ | Advance subtitles earlier by 0.2s |
| Alt + ] | Delay subtitles later by 0.2s |
| Alt + </kbd> | Reset timing offset to 0.0s |
| Alt + ↑ | Increase font size |
| Alt + ↓ | Decrease font size |
| Alt + → | Increase background opacity |
| Alt + ← | Decrease background opacity |
| Alt + W | Position subtitles at Top |
| Alt + M | Position subtitles at Middle |
| Alt + S | Position subtitles at Bottom |
- Clone or Download the Repository:
git clone https://github.com/IbraTech04/subly cd subly - Open your browser's extension manager:
- Chrome:
chrome://extensions/ - Edge:
edge://extensions/ - Brave:
brave://extensions/
- Chrome:
- Enable Developer Mode:
- Toggle the "Developer mode" switch in the top-right corner.
- Load the extension:
- Click Load unpacked.
- Select the
sublydirectory. - ✅ Subly is now active in your browser toolbar!
- Open any video on YouTube.
- Drag your subtitle file (
.srtor.vtt) from your file manager and drop it onto the video player. - Subtitles appear and sync with playback immediately!
- Open your desired YouTube video.
- Click the Subly icon in your browser toolbar.
- Select a file from your computer or paste an online subtitle URL and click Fetch.
- Click 🚀 Inject Subtitles.
- Switch to the ⏱️ Sync or 🎨 Styling tabs to fine-tune timing delay and appearance.
This project is licensed under the MIT License - see the LICENSE file for details.
We welcome contributions from the community! Whether it's bug fixes, feature additions, or documentation improvements, your help makes Subly better for everyone.