Javascript port of the heroprotocol Python library to decode Heroes of the Storm replay protocols.

Usage no npm install needed!

<script type="module">
  import heroprotocoljs from 'https://cdn.skypack.dev/heroprotocoljs';



heroprotocoljs is a Javascript port of heroprotocol. It is a library and standalone tool to decode Heroes of the Storm replay files into Javascript data structures.

Currently heroprotocoljs can decode these structures and events:

  • replay header
  • game details
  • replay init data
  • game events
  • message events
  • tracker events

heroprotocoljs can be used as a base-build-specific library to decode binary blobs, or it can be run as a standalone tool to pretty print information from supported replay files.

Note that heroprotocoljs does not expose game balance information or provide any kind of high level analysis of replays; it's meant to be just the first tool in the chain for your data mining application.


npm install -S heroprotocoljs


As a library

An usage example is provided in the "example" folder. It displays the map name and players name.

const heroprotocol = require('../heroprotocol');

const file = process.argv[2];

const details = heroprotocol.get(heroprotocol.DETAILS, file);

if (details) {
  const players = details.m_playerList.map(player => player.m_name.toString());

  console.log('Map:', details.m_title);
  console.log('Players:', players.sort());


Map: Battlefield of Eternity
Players: […]

As a command line tool

usage: heroprotocol.js replayFile [--help] [--gameevents] [--messageevents]
[--trackerevents] [--attributeevents] [--header] [--details] [--initdata]
[--stats] [--json]

  -h, --help             show this help                                       [boolean]
  -H, --header           parse protocol header                                [boolean]
  -d, --details          parse protocol details                               [boolean]
  -i, --initdata         parse protocol initdata                              [boolean]
  -g, --gameevents       parse protocol gameevents                            [boolean]
  -m, --messageevents    parse protocol messageevents                         [boolean]
  -t, --trackerevents    parse protocol trackerevents                         [boolean]
  -a, --attributeevents  parse protocol attributeevents                       [boolean]
  -s, --stats            print SPlayerStatsEvent                              [boolean]
  --json                 prints in JSON format                                [boolean]

To extract everything, you can use the extraction tool provided:

usage: extract.js file|dir ... outdir [-h] [-p] [-r] [-v]

-h, --help       show this help                                      [boolean]

-p, --pretty     prettifies the json                                 [boolean]

-r, --recursive  scans input folders for replays recursively         [boolean]

-v, --verbose    prints additional info                              [boolean]

Data reference

The following files are in the archive and supported by the library:

  • replay.details (see reference/replay.details.md for details)
  • replay.initdata (see reference/replay.initdata.md for details)
  • replay.game.events
  • replay.message.events (see reference/replay.message.events.md for details)
  • replay.tracker.events (see reference/replay.tracker.events.md for details)
  • replay.attributes.events

Also accessible is the replay header (see reference/header.md for details).

The following files are in the archive but not supported by this port nor the original library yet:

  • replay.load.info
  • replay.resumable.events
  • replay.server.battlelobby
  • replay.smartcam.events
  • replay.sync.events
  • replay.sync.history

Supported Versions

heroprotocoljs supports all protocols avalaible in the original library and can read all replays from retail versions of the game, up to and including patch 16.0. The plan is to port all future versions as they become available.

How it works

Heroes of the Storm replay files are MPQ archives. heroprotocol uses the mpyq library to read and extract the binary content out of the archive. It then parses the binary content into data structures containing the replay information.

The three main files are:

  • decoders.js: Contains the binary structures decoders. They are the same for all versions of the game.
  • protocol#####.js: Contains the data structures description of a specific public release of the game.
  • heroprotocol.js: Entry point. Exports the ReplayDecoder and provides the CLI.

heroprotocol.js starts by loading the earliest protocol available, protocol29406.js and uses it to parse the replay header. It then reads the replay build version in the header and loads the associated protocol#####.js containing the correct data structures to parse the full replay.


What I always wanted for personal use is a bulk analyzer that takes all your replays and give you stats, so that's my end goal for now. If it goes well I'd like to provide a website for anyone to see their stats whithout having to install this tool. Along the way I hope I can provide tools to read individual or multiple replays and all information associated in a friendlier way than Blizzard's data structures. I would also like to build a reference for those data structure. Finally I would like to explore the possibility of using this library directory in the browser, as while hard it's certainly feasible and would help third-party tool creation greatly.

Any small or big contribution appreciated whether in code, documentation, feedback or feature request.


Blizzard Entertainment for making the awesome Heroes of the Storm game and releasing the original heroprotocol tool.

The standalone tool uses a javascript port of mpyq to read mopaq files.


Copyright (c) 2016, Mathieu Merdy

Copyright (c) 2015 Blizzard Entertainment

Open sourced under the ISC license and MIT license. See the included LICENSE file for more information.