Zeebe clients connect to brokers via a stateless gateway. For the communication between client and gateway gRPC is used. The communication protocol is defined using Protocol Buffers v3 (proto3), and you can find it in the Zeebe repository.

What is gRPC?

gRPC was first developed by Google and is now an open-source project and part of the Cloud Native Computing Foundation. If you’re new to gRPC, the “What is gRPC” page on the project website provides a good introduction to it.

Why gRPC?

gRPC has many nice features that make it a good fit for Zeebe. It:

  • supports bi-directional streaming for opening a persistent connection and sending or receiving a stream of messages between client and server
  • uses the common http2 protocol by default
  • uses Protocol Buffers as an interface definition and data serialization mechanism–specifically, Zeebe uses proto3, which supports easy client generation in ten different programming languages

Supported clients

At the moment, Zeebe officially supports two gRPC clients: one in Java, and one in Golang.

If Zeebe does not provide an officially-supported client in your target language, you can read the official Quick Start page to find out how to create a very basic one.

You can find a list of existing clients in the Awesome Zeebe repository. Additionally, a blog post was published with a short tutorial on how to write a new client from scratch in Python.