ArduPilot Parameter File Diff — compare .param files with parameter meanings
Free online ArduPilot/PX4 .param file comparison tool: paste two parameter files and see exactly what changed, what was added, and what was removed — each one annotated with the official parameter description, units, and valid values. Runs entirely in your browser.
Why the parser handles three different file formats
| Format | Where it comes from | Example |
|---|---|---|
| Comma-separated | Mission Planner's common "Save to file" export, shared on forums | ATC_RAT_YAW_P,0.3 |
| Whitespace-separated | ArduPilot's own SITL default-parameter files | ATC_RAT_YAW_P 0.3 |
| 5-column MAVLink | QGroundControl's standard parameter-file format | 1 1 ATC_RAT_YAW_P 0.3 9 |
Malformed lines (non-numeric values, unparseable rows, duplicate parameter names) are reported as warnings, never silently dropped or silently guessed. Floating-point comparison uses a small epsilon so a file re-saved by a different ground station (which rounds differently — 0.1 vs 0.100000) doesn't show a false "changed" row.
Parameter names, descriptions, units, and valid values are sourced from ArduPilot's own official metadata (apm.pdef.xml, generated by ArduPilot's param_parse.py and published at autotest.ardupilot.org) — the same source ground stations like Mission Planner use, not a hand-maintained guess. Coverage: 5,702 ArduCopter parameters, 5,747 ArduPlane, 5,455 Rover.
Scope (honest): this compares two static files — it doesn't connect to a vehicle, and it doesn't know which ArduPilot firmware version either file was saved from (parameter meanings occasionally change between major releases). A name with no annotation below is either a custom/scripting parameter, or one renamed/removed since the metadata was last generated. PX4 parameter file support isn't included yet — PX4's metadata is board- and build-specific with no single stable download URL, unlike ArduPilot's static per-vehicle XML.
Debugging why a config change made your aircraft behave differently, or setting up a fleet of vehicles that need to share a tuning baseline? That's exactly the kind of thing I help with — work with me →