Licensing

This page covers the commercial product license for the Trellis CLI binary and Docker images — what is free, what needs a paid license key, and how to activate it. The binary itself is proprietary; see the EULA.

Note — two different licenses. The source files in the public Trellis repository (docs, MCP server wrapper, provisioning scripts) are open source under the MIT License. That is separate from the commercial product license described below, which governs the binary and its paid features.

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.

Usage telemetry

Licensed users receive anonymous usage pings when running commands. No personal data, no file content, no machine identifiers — only the command name, CLI version, and a one-way fingerprint of the license key. See Telemetry for the exact data structure and opt-out instructions.

Questions

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