dm_diff_tool

Matter Data Model Diff Checker

A browser-based diff tool for comparing Matter specification data models across versions. It parses the official XML cluster and device-type definitions and produces a structured, searchable diff.

What It Does

This tool lets you pick any two Matter spec versions and instantly see what changed:

• Added / Removed / Modified clusters — with full detail down to individual attributes, commands, events, features, data types, and their fields.
• Added / Removed / Modified device types — including cluster requirements, condition requirements, features, and commands.
• Revision tracking — highlights clusters or device types whose content changed but whose revision number was not bumped ("No Revision Update" warnings).
• Deep search — type any term (an attribute name, a command, an event, a feature flag, an enum value) and the tool filters the diff to show only matching elements, even inside nested structures.
• Export — download the computed diff as a JSON file for offline analysis or integration with other tooling.

Screenshots

Dark Mode	Light Mode

Running Locally

build_tool.sh builds the local data files (see below) and, with --serve, starts a static HTTP server:

cd dm_diff_tool

./build_tool.sh --serve          # add --port 9000 to change the port

Then open http://localhost:8000 in your browser.

If you already have the data files built and just want to serve the directory, any static HTTP server works (e.g. python3 -m http.server 8000).

First-load note: The tool downloads the Pyodide Python runtime (~20 MB) on the first visit. A loading spinner is shown during this time. Subsequent loads are faster once the browser has cached the runtime.

Adding or Updating a Matter Version

Neither the raw XML files nor the built zips are committed — the deploy CI builds everything from connectedhomeip on every push to main.

To build locally for development:

# Auto-clones connectedhomeip (data_model/ only) into /tmp, then builds zips:
./build_tool.sh

# Or, if you already have a local connectedhomeip checkout:
MATTER_SDK_PATH=/path/to/connectedhomeip
./build_tool.sh

# Add --serve to build and then open a local server in one step:
./build_tool.sh --serve

This reads $MATTER_SDK_PATH/data_model/{version}/clusters/ and $MATTER_SDK_PATH/data_model/{version}/device_types/, produces one zip per version under data_model/zips/, and regenerates data_manifest.json.