Kandle

Free, open-source charts for crypto, stocks and forex, and your AI agent can drive them.

Indicators, drawing tools, your own scripts and strategy backtests, alerts, bar replay and up to four charts on screen. No account, no paywall, no limit on indicators. It runs in your browser and keeps everything on your machine.

Claude Code, Codex, Cursor or Gemini CLI can read the chart, draw support and resistance, add indicators, write scripts and set alerts while you watch.

Open Kandle in your browser · Connect your agent · Write a script

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Connect your agent in one line

claude mcp add kandle -- npx -y --package=https://github.com/Kernel-Hunter/kandle/releases/download/v0.10.1/kandle-mcp-0.10.1.tgz kandle-mcp

Then open Kandle, click Agent, paste the pairing code your agent gives you and turn on Agent bridge. Ask it something like "mark the last swing high and low on BTC and draw a Fibonacci retracement between them". Setup for other agents is below.

Features

• Live crypto candles from Binance, Coinbase, Bybit, OKX and Kraken public market data, with no key. History loads over REST and updates stream over websockets.
• US and global stocks, ETFs and forex from Twelve Data, Alpaca or Polygon with your own free API key. See Data sources.
• Your own OHLCV data from a CSV file, kept in your browser. See CSV import.
• Symbol search for the chosen source, with Crypto, Stock, ETF, Forex, Index and CSV badges.
• Timeframes: 1m, 5m, 15m, 1H, 4H, 1D, 1W. Scroll left to load older history.
• Chart types: candles, hollow candles, bars (OHLC), line, area and Heikin Ashi, with a normal, logarithmic or percent price scale. Each chart in a layout keeps its own. Heikin Ashi only changes how bars are drawn: indicators, scripts, backtests, alerts and the agent tools keep using the real prices, and the legend shows the Heikin Ashi values on their own line.
• 36 indicators, with as many on the chart as you like: MA, EMA, SMA, WMA, HMA, Bollinger Bands, Donchian Channel, VWAP, Supertrend, Parabolic SAR, Ichimoku Cloud, Volume Profile, Volume, MACD, RSI, Stochastic RSI, KDJ, ATR, OBV, CCI, DMI/ADX, Williams %R, ROC, Momentum, TRIX, Awesome Oscillator and more. Every parameter can be edited.
• Ichimoku Cloud with the cloud drawn ahead of the last candle, and a volume profile of the bars on screen that marks the point of control and the value area. The profile updates as you scroll and zoom.
• Drawing tools: trend line, ray, extended line, horizontal line and ray, vertical line, parallel channel, rectangle, Fibonacci retracement, price range, text notes and price labels. Select a drawing to move it or delete it. An optional magnet snaps points to candle prices.
• Your symbol, timeframe, chart type, price scale, theme, indicators, and drawings (saved per symbol) come back when you reload.
• Dark and light themes.
• Keyboard shortcuts for most actions. Press ? in the app to see them all.
• Export the chart as a PNG image.
• Share a chart as a link: symbol, timeframe, chart type, indicators and drawings, plus scripts and the multi-chart layout if you choose. The link carries the chart itself. See Share a chart. The same popover gives an iframe that shows the chart on a blog or docs page, see Embed a chart.
• Scripts: write your own indicators in Kandle Script, with an editor under the chart and 14 example scripts. Scripts can read other timeframes and other symbols with request.security.
• Strategy backtests: write a strategy script, see its trades on the chart, and get net profit, drawdown, win rate, an equity curve and the list of trades.
• Alerts on price levels, drawn lines and indicator values, with browser notifications.
• Bar replay to step through history one candle at a time.
• 1, 2 or 4 charts on screen, each with its own symbol, timeframe and indicators.
• A watchlist next to the charts with live prices and 24 hour change for crypto, and the change since the previous close for stocks and forex. Click a symbol to open it.
• An MCP server so AI agents can read the chart, draw on it, set alerts and take screenshots.
• Works on desktops, tablets and phones. On a narrow screen the top bar keeps the symbol, timeframe and price in view and moves the other tools into the ... menu.

Keyboard shortcuts

| Keys | Action | | --- | --- | | Any letter or digit | Search symbols | | / or Alt+I | Indicators | | Alt+S | Script editor | | Ctrl+Enter or Cmd+Enter | Add or update the script on the chart (in the editor) | | Alt+1 to Alt+7 | Timeframes 1m to 1W | | Alt+C | Next chart type | | Alt+T | Trend line | | Alt+R | Ray | | Alt+H | Horizontal line | | Alt+V | Vertical line | | Alt+B | Rectangle | | Alt+F | Fibonacci retracement | | Alt+P | Price range | | Alt+N | Text note | | Alt+M | Magnet on or off | | Delete | Delete the selected drawing | | Esc | Cancel the current drawing or close a dialog | | Alt+L | Switch between light and dark | | Alt+W | Show or hide the watchlist | | Alt+K | Share a link to this chart |

Use it with your AI agent

Kandle ships an MCP server, kandle-mcp. Your agent starts it, and the Kandle tab in your browser connects to it over a WebSocket on 127.0.0.1. The agent can then read the chart and change it while you watch.

Set up

1. Add the server to your agent (the snippets are below).
2. Ask the agent for the Kandle pairing code. It calls get_bridge_status and shows a code like K7QD-9MXR-2HPA. The code is also saved in ~/.kandle/bridge-token.
3. In Kandle, click Agent in the top bar, paste the code, and turn on Agent bridge. The dot on the button turns green when the agent is connected.

The code is saved in your browser and in ~/.kandle/bridge-token, so you only pair once.

This works with the hosted app and with a copy you run yourself. With the hosted app, your browser may ask whether the page can reach devices on your local network; allow it so the page can talk to kandle-mcp on 127.0.0.1.

npx runs kandle-mcp from a GitHub release, so you only need Node.js 22.12 or newer. When a new version of Kandle comes out, change the version in the URL; get_bridge_status tells your agent when the app is newer than its server. To run it from a clone instead, use pnpm install && pnpm build and point your agent at node /path/to/kandle/packages/mcp/bin/kandle-mcp.js.

Claude Code:

claude mcp add kandle -- npx -y --package=https://github.com/Kernel-Hunter/kandle/releases/download/v0.10.1/kandle-mcp-0.10.1.tgz kandle-mcp

Codex (~/.codex/config.toml):

[mcp_servers.kandle]
command = "npx"
args = ["-y", "--package=https://github.com/Kernel-Hunter/kandle/releases/download/v0.10.1/kandle-mcp-0.10.1.tgz", "kandle-mcp"]

Cursor (~/.cursor/mcp.json or .cursor/mcp.json in a project) and Gemini CLI (~/.gemini/settings.json):

{
  "mcpServers": {
    "kandle": {
      "command": "npx",
      "args": ["-y", "--package=https://github.com/Kernel-Hunter/kandle/releases/download/v0.10.1/kandle-mcp-0.10.1.tgz", "kandle-mcp"]
    }
  }
}

Claude Desktop: download kandle-mcp-0.10.1.mcpb and open it to install the server.

Kandle is also listed in the MCP Registry as io.github.Kernel-Hunter/kandle, so clients that browse the registry can find it.

Tools

| Tool | What it does | | --- | --- | | get_bridge_status | Connection state and the pairing code | | get_chart_state | Symbol, timeframe, last bar, visible range, indicators with latest values, drawings with ids, alerts, replay and layout. Note text is limited to 20 notes of 120 characters and marked as untrusted | | set_symbol, set_timeframe | Change the market or bar size. Exchange csv opens a dataset you imported | | get_candles | OHLCV bars by count or time range, optionally with indicator values per bar | | add_indicator, remove_indicator, list_indicators | Manage indicators and list the 36 available | | draw | Trend line, horizontal line or ray, vertical line, ray, extended line, rectangle, Fibonacci retracement, text note, price range, all by price and time | | remove_drawing, clear_drawings | Remove drawings | | screenshot | PNG of a chart, returned as an image | | set_alert, list_alerts, remove_alert | Alerts on price, drawn lines and indicators | | start_replay, step_replay, stop_replay | Bar replay | | set_layout | 1, 2 or 4 charts, sync options, symbol and timeframe per chart | | set_chart_style | Chart type (candles, hollow candles, bars, line, area, Heikin Ashi) and price scale (normal, log, percent) of a chart | | get_watchlist, add_to_watchlist, remove_from_watchlist | Watchlist symbols with last price, change and change percent, and adding or removing them | | run_script | Adds a Kandle script to the main chart and returns its id, input values and latest plot values, or the error with line and column. inputs sets input values by title and id replaces a script added earlier. For a strategy it also returns the backtest summary and the last 20 trades, and strategy changes its backtest settings | | get_backtest | Settings (and which ones differ from the script), summary and up to 500 trades of a strategy script on the chart | | get_share_link | A link that opens the main chart for anyone. include picks what it carries besides the exchange, symbol and timeframe. embed: true adds an iframe for another web page |

Most tools take an optional pane (1 to 4) when several charts are showing. Times can be ISO 8601 dates or Unix times in seconds or milliseconds. Inputs are validated and errors say what to fix.

skills/kandle/SKILL.md is an agent skill with chart analysis workflows: support and resistance, trend, indicator confluence, and annotating a chart with an explanation. Copy it into your agent's skills folder (for Claude Code, ~/.claude/skills/kandle/).

Security model

• The bridge only listens on 127.0.0.1. Nothing is reachable from other machines.
• The app connects to the server, not the other way round, and only after you turn on Agent bridge. It is off by default and you can turn it off at any time.
• Every connection must send the pairing code first. The code has about 59 bits of randomness, is compared in constant time, and the server stops accepting codes for a minute after 5 wrong ones.
• The server rejects WebSocket connections from web pages that are not served from localhost, 127.0.0.1 or [::1], so a website you visit cannot connect even if it guesses the port. The hosted app at https://kernel-hunter.github.io is also allowed. Add other origins, such as your own hosted copy, with KANDLE_ALLOWED_ORIGINS.
• The server rejects requests whose Host header is not a loopback address, which blocks DNS rebinding.
• Drawing notes can come from a link so