Licensing

Trellis is free to use for everyday rendering. Some advanced capabilities are commercial features that require a license key.

What’s free

Rendering single diagrams with trellis render (PNG)
Syntax validation with trellis validate
The VS Code extension live preview and PNG creation
The browser-based live editor
MCP server to render PNG images out of mermaid definition

What needs a license

Feature	Where
`render-batch` — render a whole directory at once	CLI
SVG / HTML / Draw.io output	–license-key `KEY` command line argument or `TRELLIS_KEY` env variable required
SVG / HTML / Draw.io output via the MCP server	MCP server (`TRELLIS_KEY` required)

Each activated device consumes one seat from your license.

👉 Subscribe to Trellis

After subscribing you’ll receive a license key. Activate it on each device you use.

Activating a license (CLI)

# Activate this device (consumes one seat)
trellis license activate --license-key YOUR_KEY

# Show current status and device instance
trellis license status

# Deactivate this device (frees the seat)
trellis license deactivate

Key resolution order

When a command needs a license, the key is resolved in this priority order:

--license-key KEY passed on the command line
TRELLIS_KEY=... in a .env file in the working directory
TRELLIS_KEY environment variable

# .env file approach
echo "TRELLIS_KEY=YOUR_KEY" > .env
trellis license activate

License key for the MCP server

The MCP server requires TRELLIS_KEY to be set for SVG, HTML, and Draw.io output:

export TRELLIS_KEY=YOUR_KEY

Or set it in the MCP client configuration env block — see the MCP guide.

Questions

For licensing questions, seat counts, or team plans, contact us via the issues page or the subscribe link above.