Kanban without the noise. Single-HTML-file, local-first Trello alternative. Zero server, zero account, zero board limits.

Live: kanzen.naklitechie.com

Boards live on your device — as plain .kanzen.json files in a folder you choose. Period.

Kanban + Zen (simplicity). Also 完全 (kanzen) — Japanese for "complete" or "perfect."

• One self-contained index.html — open the file, it works
• File System Access API as the source of truth — each board is one human-readable JSON file
• IndexedDB fallback for browsers without FS API, or before you grant folder permission
• No build step, no dependencies, no telemetry, no account
• Drop the folder in Dropbox / iCloud / Syncthing / git → multi-device for free

Boards & cards

• Multiple boards with a switcher
• Columns: create, rename, reorder by drag, delete, collapse, soft WIP limits
• Cards: title, markdown description, due date, priority, labels, members, checklists, file attachments, comments
• Drag-and-drop cards between and within columns
• Per-board background (gradient / solid / custom colour)

Views

• Board (kanban), List (sortable table), Calendar (month grid with drag-to-set-due-date)
• Global search and filters (label, priority, due bucket, member) — non-matching cards dim instead of hiding

History & sharing

• Snapshots: manual or auto (before destructive actions, optional daily). Compare any two snapshots — card-level diff (added / removed / modified)
• Undo / redo (Cmd/Ctrl+Z and Shift+Z), 50-deep per board
• Activity feed of every change
• URL sharing: encrypted (AES-GCM 256, PBKDF2 200K) or plain, compressed via the browser-native CompressionStream API (no CDN dependency on modern browsers), with size gate and QR code. The hash fragment never leaves the browser. Read-back supports the spec #e= format too, so URLs from compatible tools can be imported.

Storage & interop

• File System Access API as the source of truth — pretty-printed, sorted-key JSON for clean git diffs
• Stable filenames that survive board renames (no orphaned files on disk)
• Folder handle persisted between sessions where the browser allows it (Chrome)
• 5-second polling for external edits — if you sync via git/Dropbox/iCloud, the other device's changes appear as a "Board updated from disk" toast
• Team mode (per-board toggle): splits a board into _board.json + cards/<id>.json + _activity.jsonl so each card edit touches only that one file. Two people editing different cards never produce a merge conflict. Lossless toggle in both directions.
• Cloud sync (optional, BYO Cloudflare Worker): deploy a 3-minute Worker in your own Cloudflare account, set a passphrase in Preferences, and KanZen syncs boards across devices via your own infrastructure. AES-GCM 256 encrypted client-side — the Worker only ever sees ciphertext. Tier-1 conflict resolution (same user, different device) is automatic; tier-3 (different user) prompts. Pre-conflict snapshots are taken before any overwrite.
• IndexedDB fallback when no folder is connected; "Browser storage only" pill nudges you to wire up a folder
• Auto-save every 5 s on changes; immediate save on destructive actions
• Per-board and full-state JSON export / import (merge or replace)
• CSV and Markdown export
• Trello JSON import (lists, cards, labels, members, checklists)
• Card-level audit trail: every card carries createdBy/createdAt/lastModifiedBy/lastModifiedAt and the activity log records every change with structured detail (filterable by user, action, card)
• PWA-lite: inline manifest, installable as an app

UI

• Dark / light theme
• Palette picker (🎨 in the header) — switch between Trello-default and curated Rangrez palettes (SUMI, KINARI, TADELAKT, SANG, SNÖ, MUMBAI ART DECO). Choice persists per browser.
• Keyboard shortcuts: N new card, E edit, / search, arrows to navigate, Cmd/Ctrl+Z undo
• Touch: long-press a card → "Move to" popover
• ARIA roles, prefers-reduced-motion and prefers-contrast support

KanZen ships with seven runtime-switchable palettes. Click the 🎨 icon in the top-right to open the picker:

Palettes come from the Rangrez library — 240 palettes with country-specific color stories. Your choice is persisted in localStorage (key kanzen.palette) and survives reloads.

Just visit kanzen.naklitechie.com in any modern browser. Or, to host it yourself:

python3 -m http.server 8000
# then visit http://localhost:8000/

The File System Access API requires HTTPS or localhost. IndexedDB fallback works from file:// too.

Nothing leaves your machine. There is no server. The author cannot see your boards. Even share URLs encode the board into the hash fragment, which is never sent to any server — not even to Cloudflare Pages, where this site is hosted.

Chirag Patnaik — part of the NakliTechie browser-native tools series.