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Rattletrap parses and generates Rocket League replays. Parsing replays can be used to analyze data in order to collect high-level statistics like players and points, or low-level details like positions and cameras. Generating replays can be used to modify replays in order to force everyone into the same car or change the map a game was played on.

Rattletrap supports every version of Rocket League up to 1.78, which was released on 2020-06-16. If a replay can be played by the Rocket League client, it can be parsed by Rattletrap. (If not, that's a bug. Please report it!)

Rattletrap is a command-line application. You should only use it if you're comfortable running things in terminals or command prompts. Otherwise consider using another tool like Ball Chasing. Rattletrap is written in Haskell. If you'd like to use a program written in a different language, consider @jjbott's C# parser or @nickbabcock's Rust parser.


Get Rattletrap by downloading the latest release for your platform.

Rattletrap is also available as a Docker image.

To build Rattletrap from source, install Stack. Then run stack --resolver lts-14.25 install rattletrap.


Rocket League saves your replays in a folder that depends on your operating system.

  • Windows:
    • %UserProfile%/Documents/My Games/Rocket League/TAGame/Demos
    • For example: C:/Users/Taylor/Documents/My Games/Rocket League/TAGame/Demos
  • macOS:
    • $HOME/Library/Application Support/Rocket League/TAGame/Demos
    • For example: /Users/taylor/Library/Application Support/Rocket League/TAGame/Demos
  • Linux:
    • $HOME/.local/share/Rocket League/TAGame/Demos
    • For example: /home/taylor/.local/share/Rocket League/TAGame/Demos


Rattletrap is a command line application.

$ rattletrap --help
rattletrap version 9.0.1
  -c           --compact         minify JSON output
  -f           --fast            only encode or decode the header
  -h           --help            show the help
  -i FILE|URL  --input=FILE|URL  input file or URL
  -m MODE      --mode=MODE       decode or encode
  -o FILE      --output=FILE     output file
  -v           --version         show the version

By default Rattletrap will try to determine the appropriate mode (either decode or encode) based on the file extensions of the input or output. You can override this behavior by passing --mode (or -m) with either decode or encode.

Input extension Output extension Mode
.replay anything decode (parse)
.json anything encode (generate)
anything .replay encode (generate)
anything .json decode (parse)
anything anything decode (parse)


Rattletrap can parse (decode) Rocket League replays and output them as JSON.

$ rattletrap --input --output output.json
# or
$ rattletrap -i input.replay -o output.json
# or
$ rattletrap < input.replay > output.json

The input argument can either be a local path or a URL.

By default the JSON is pretty-printed. To minify the JSON, pass --compact (or -c) to Rattletrap. Even when the JSON is minified, it's extremely large. The output can be up to 100 times larger than the input. For example, a 1.5 MB replay turns into 31 MB of minified JSON or 159 MB of pretty-printed JSON.


Rattletrap can also generate (encode) Rocket League replays from JSON files.

$ rattletrap --input --output output.replay
# or
$ rattletrap -i input.json -o output.replay
# or
$ rattletrap --mode encode < input.json > output.replay

The input argument can either be a local path or a URL.

If the JSON was generated by Rattletrap, the output replay will be bit-for-bit identical to the input replay.


By inserting another program between parsing and generating, Rattletrap can be used to modify replays.

$ rattletrap -i input.replay |
  modify-replay-json |
  rattletrap -o output.replay
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