Jot

Jot is a Chrome extension for recording your current browser tab without sending your video to any server. It is designed for quick demos, bug reports, walkthroughs, and tutorials where privacy and speed matter.

The core idea is simple: click record, capture the tab you are already on, process the video locally, and download an MP4 that stays on your machine.

Screenshots

Features

• One-click recording of the active browser tab
• No account, no upload, no cloud processing
• Local MP4 export for broad compatibility
• Crash-tolerant chunk storage using OPFS
• Adaptive quality selection based on device capabilities
• Useful for demos, bug reports, product walkthroughs, and tutorials

Why I Built This

Most screen recording tools optimize for sharing through the cloud. I wanted the opposite workflow: fast recording that stays private by default.

Jot solves that by making local-first recording the default behavior. Your video never leaves your device.

Technical Highlights

• Capture: Chrome tabCapture API for direct tab recording
• Encoding: WebCodecs for efficient in-browser encoding
• Storage: OPFS for durable local chunk persistence
• Processing: FFmpeg compiled to WebAssembly for MP4 output

Technologies Used

• Platform: Chrome Extension (Manifest V3)
• Browser APIs: tabCapture, WebCodecs, OPFS, Web Workers
• Media Processing: FFmpeg WebAssembly

Links

• Chrome Web Store: Jot — Screen Recorder
• Blog Post: I Built a Screen Recorder That Never Uploads Your Video