FilePeek: View & Edit CSV, JSON & Markdown

View and edit CSV, JSON, and Markdown files in your browser. Sortable tables, JSON tree, live Markdown editor, local file save.

FilePeek turns your browser into a fast, beautiful viewer and editor for the data files you work with every day. Open a local or web CSV, JSON, or Markdown file and FilePeek renders it instantly — no more raw text walls or forced downloads. ■ CSV / TSV - Local .csv files open as a clean, sortable table instead of downloading - Column sorting (numeric-aware), instant full-text filtering - Inline cell editing — click Edit, change cells, then Save back to the original file - EUC-KR decoding for Korean Excel exports, BOM-safe saving - Copy as TSV for direct pasting into Google Sheets or Excel - Timestamped copies (file_20260823-0135.csv) for quick versioning ■ JSON - Collapsible tree view with syntax colors, fully expanded on open - Raw / Parsed toggle, one-click copy - URLs become clickable links - Alt+click to expand or collapse entire subtrees - Lazy rendering keeps huge files fast ■ Markdown - GitHub-style rendering with dark/light mode - Resizable table of contents sidebar - Split-screen editor with live preview (Cmd/Ctrl+S to save) - Save back to the original local file, or download a timestamped copy - Emphasized inline code styling for better readability ■ Theme - Follows your system light/dark mode, or force Light / Dark from the toolbar toggle (shared across all viewers) ■ Private by design - Everything runs 100% locally in your browser - No servers, no analytics, no data collection — ever ■ Setup note - To open local files, enable "Allow access to file URLs" for FilePeek on chrome://extensions (Chrome requires this opt-in for every extension).