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Hedera Hashgraph Protocol Buffer API Message Definitions

The Hedera Hashgraph API is implemented with protocol buffers, Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data. This repository contains the current version of the files used to define the API.


The protobuf files themselves contain detailed comments which help understand not only the message itself but also some of the features and capabilities of the Hedera Hashgraph network.

The /docs folder of this project contains automatically generated documents in html and markdown format to help navigate through the message definitions.

NestedDoc.html - nested HTML document to help navigate messages that contain other message definitions (large document that takes a while to open) NotNestedDoc.html - flat HTML document - flat markdown document

Note: the HAPI.html document is a large document and may take a few seconds to load in a browser.

Additional resources

If you are unfamiliar with protocol buffers (or need a refresher), you may consult the following web resources:

Deploy to Maven

You will need the appropriate credentials to do so

  • Update the version number in the pom.xml (ensure pom.xml has x.x.x-SNAPSHOT for version)
  • Build the project with mvn clean install
  • Re-generate the documentation
cd docgenerator
java -jar proto2html.jar "HAPI Documentation" ../src/main/proto/ ../docs
cd ..

Commit all changes to github

mvn release:clean release:prepare (you will be prompted to confirm version numbers, etc...)

mvn release:perform

navigate to Nexus Repository Manager and release the newly created repository.