Niffler

A warm, keyboard-first terminal Kanban board built on plain local Markdown files.

Niffler is a local-first TUI Kanban app built with Rust, Crossterm, and Ratatui. It keeps boards as plain directories and cards as ordinary Markdown files, with lightweight .niffler.yaml metadata for board settings, list order, colors, theme, and preview state.

There is no database and no lock-in. Your cards are just .md files, so you can move them into another notes app, commit them to Git, sync them with Dropbox/iCloud/Syncthing, publish them, archive them, or edit them with any text editor.

The interface is designed to feel like a polished terminal tool: fast navigation, compact status bars, modal command cards, and a warm gold palette inspired by a magical collector's notebook.

Demo

Features

• Board browser with live board details
• Full-screen Kanban board view
• Keyboard-only list and card navigation
• Create, rename, delete, and move boards, lists, and cards
• Optional card preview panel, persisted per board
• Portable local Markdown cards with frontmatter metadata
• External editor support via NIFFLER_EDITOR or EDITOR
• Local data storage with no server

Install

Install the Niffler package from crates.io:

cargo install niffler-tui

Then launch the app with the niffler command:

niffler

The crates.io package is named niffler-tui because niffler is already used by another crate. The installed command remains niffler, so the end-user experience keeps the Niffler name.

For local development, run directly from the repository:

cargo run

Data Location

By default, Niffler stores data in:

~/.niffler

Override it with:

export NIFFLER_HOME=/path/to/boards

A board looks like this:

~/.niffler/
  config.yaml
  my-board/
    .niffler.yaml
    todo/
      first-card.md
    done/
      shipped.md

Cards are regular Markdown files. Niffler only adds small frontmatter fields such as position, created_at, and updated_at.

Global display settings live in config.yaml. Niffler writes default theme and picker colors there, so every board shares the same palette:

theme:
  active_selection: "#daad52"
  selected_text: "black"
  panel: "#976f3a"

colors:
  - label: Default
    value: "#3c3c3c"
  - label: Red
    value: "#ef4444"

Board-local settings stay in each board's .niffler.yaml:

name: My Board
show_preview: false

lists:
  - id: todo
    title: Todo
    position: 1000
    border_color: "#ef4444"

That means you can take a card out of Niffler at any time:

todo/plan-new-field-guide.md

Open it in another editor, move it to another project, store it in a Git repo, or use it as a normal note. The content remains Markdown.

Editor

When editing a card, Niffler chooses an editor in this order:

NIFFLER_EDITOR
EDITOR
vi

Examples:

export NIFFLER_EDITOR=nvim
export NIFFLER_EDITOR="code --wait"

Shortcuts

Home

Key	Action
j / k or Up / Down	Move board selection
Enter	Open board
n	New board
r	Rename board
d	Delete board
?	Help
q	Quit

Board

Key	Action
j / k or Up / Down	Move between cards
h / l or Left / Right	Move between lists
Tab / Shift+Tab	Next / previous list
n	New card
N	New list
e	Edit card
s	Search cards by title
m	Move card
M	Move list
C	Change list border color
r	Rename card
R	Rename list
d	Delete card
D	Delete list
p	Toggle preview
?	Help
Esc	Back to board browser
q	Quit

Development

Run tests:

cargo test

Check formatting:

cargo fmt --check

Philosophy

Niffler is meant to stay simple:

• Plain files over opaque databases
• Portable Markdown over app lock-in
• Fast keyboard workflows over mouse-heavy UI
• Compact terminal-native layouts over decorative screens
• Durable Markdown cards over app-specific content formats