Python library to decode Heroes of the Storm replays

pip install heroprotocol==



heroprotocol is a Python library and command-line tool to decode Heroes of the Storm replay files into Python data structures.

The tool is available as a PyPI Package or as source code.

Currently heroprotocol can decode these structures and events:

  • Replay header
  • Game details
  • Replay init data
  • Game events
  • Message events
  • Tracker events

heroprotocol 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 heroprotocol 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.

Supported Versions

heroprotocol supports all Hereos of the Storm replay files that were played with retail and PTR versions of the game.


  • Python 2.7 or 3.x
    • Note: A future release may remove support for Python 2.7
  • Python Packages:
    • mpyq 0.2.5+
    • six 1.14.0+


Either install/update using pip:

python -m pip install --upgrade heroprotocol

Or clone the repository and run from source:

git clone
python -m pip install -r ./heroprotocol/heroprotocol/requirements.txt

Command Line Arguments

-h, --help          Show the options that are available.

Tracker Events:
--gameevents        Print all game events including coordinates
--messageevents     Print message events such as ping events
--trackerevents     Print tracker events such as units killed, game stat events,
                    score result event
--attributeevents   Print attribute events, a table of attrid, namespace, and attribute values
--header            Print protocol header including build id and elapsedGameLoops
--details           Print protocol details, e.g. teamId, player names and chosen heroes,
                    player region, game result, observer status
--initdata          Print protocol initdata, e.g. interface settings for every player

Output Options:
--stats             Output stats about the active tracker event to the STDERR stream
--json              Use JSON syntax for output

Example Usage

If you want the output shown directly in the terminal, leave out the > output.txt.

python -m heroprotocol --details "Blackheart's Bay.StormReplay" > output.txt

By default, data is output as a Python dictionary object. To output a JSON file, add --json.

Note, however, that the JSON file is formatted as a sequence/stream of JSON objects and will likely not parse as regular JSON.

Tracker Events

Some notes on tracker events:

  • Convert unit tag index, recycle pairs into unit tags (as seen in game events) with protocol.unit_tag (index, recycle)
  • Interpret the NNet.Replay.Tracker.SUnitPositionsEvent events like this:
unitIndex = event['m_firstUnitIndex']
for i in range(0, len(event['m_items']), 3):
    unitIndex += event['m_items'][i + 0]
    x = event['m_items'][i + 1] * 4
    y = event['m_items'][i + 2] * 4
    # unit identified by unitIndex at the current event['_gameloop'] time
    # is at approximate position (x, y)
  • Only units that have inflicted or taken damage are mentioned in unit position events, and they occur periodically with a limit of 256 units mentioned per event.
  • NNet.Replay.Tracker.SUnitInitEvent events appear for units under construction. When complete you'll see a NNet.Replay.Tracker.SUnitDoneEvent with the same unit tag.
  • NNet.Replay.Tracker.SUnitBornEvent events appear for units that are created fully constructed.
  • You may receive a NNet.Replay.Tracker.SUnitDiedEvent after either a UnitInit or UnitBorn event for the corresponding unit tag.
  • In NNet.Replay.Tracker.SPlayerStatsEvent, m_scoreValueFoodUsed and m_scoreValueFoodMade are in fixed point (divide by 4096 for integer values). All other values are in integers.
  • There's a known issue where revived units are not tracked, and placeholder units track death but not birth.

Reporting Bugs

Please report bugs at the Heroes of the Storm Bug Report Forum.


The standalone tool uses mpyq by Aku Kotkavuo to read mopaq files.

Thank you to healingbrew, MGatner, koliva8245, casualMLG, and others for submitting issues and feedback.

Thank you to Christian Clauss, Jingbei Li, and Regner Blok-Andersen for contributions to the Python 3 update.

Thank you to David Joerg and Graylin Kim of GGTracker for design feedback and beta-testing of the s2protocol library that heroprotocol is based upon.

Thanks to Ben Barrett of HOTSLogs for early feedback on and beta-testing of the heroprotocol library.


Copyright 2021 Blizzard Entertainment

Source code for this project is released to the public under the MIT license. See the included LICENSE file for more information.