A desktop app for opening and inspecting super large JSON | JSONL documents.
English | 中文
Inspired by Janice.
- Built with a virtualized tree view so large files are browsed without creating a UI node for every JSON element.
- Browse JSON data as an expandable tree.
- Open files from the file picker, clipboard, drag and drop, or a command line argument.
- Search keys and values with wildcard patterns.
- Export the selected JSON branch to a new file or copy it to the clipboard.
- View very large JSON files, like >2GB documents with 100MB+ elements without heavy memory issues or UI freezes.
- Switch between light and dark themes.
- Locale support: English, Chinese, French, Japanese, Korean, Portuguese, Russian, Spanish.
- Windows 10 or MacOS (Apple Silicon) with .NET Runtime 8 or newer.
- Fully loaded and rendered a 12GB JSONL with 66M elements in approx. 100 sec. (on a HDD).
- Actual speed can vary by device hardware, especially CPU, memory capacity, storage speed, and thermal conditions.
- This result is a reference measurement, not a guaranteed speed on every machine.
Choose the search type first, then enter a pattern:
- Key: searches JSON property names.
- String: searches JSON string values.
- Number: searches numeric values.
- Keyword: searches only
true,false, ornull.
Pattern behavior:
- In String search, plain text is treated as contains.
usermatchesuser,username, andcurrent_user_id.
*is the wildcard character.user*= starts withuser*user= ends withuser*user*= containsuser
- In Key, Number, and Keyword search, patterns keep the original wildcard behavior.
Search starts from the current selection and moves forward. If nothing is found before the end of the document, Jesnote asks whether to continue searching from the top.
Download the latest packaged build from the releases page, extract it, then run the executable for your platform.
If you want to build or run from source, see CONTRIBUTION.md.
- Improve UI
- Add more Json editing tools
- GPT 5.5 for code assistance and documentation.