🚧 Experimental This extension is in its early stages. It successfully passes all relevant Quarkus integration tests, but hasn’t yet been battle-tested in production. We’d love for you to try it, push its boundaries, and share feedback to make it better.

gRPC Zero is a drop-in replacement for io.quarkus:quarkus-grpc-codegen, with one major difference:

👉 It removes the need for native protoc executables and plugins. Instead, everything runs directly on the JVM as a single, portable Java dependency.

ℹ️ io.quarkus:quarkus-grpc-codegen is what io.quarkus:quarkus-grpc extension uses (currently) to generate proto messages and services

The traditional quarkus-grpc-codegen module relies on platform-specific binaries (protoc and plugins). This approach introduces several challenges:

• ❌ OS/architecture compatibility issues – binaries must be shipped for every possible environment.
• ❌ External dependencies – requires tools that may not be available in constrained or hermetic build environments.
• ❌ Maintenance overhead – keeping native executables up to date across platforms is difficult.

gRPC Zero solves these problems by providing:

• ✅ Self-contained code generation – no native tools required.
• ✅ Full portability – identical behavior on any JVM.
• ✅ Lightweight dependency – ~1.1 MB at the time of writing.
• ✅ Consistent results – passes all Quarkus integration tests with no regressions.

The result: a safer, smaller, more reliable way to enable gRPC codegen in Quarkus projects.

Instead of relying on external protoc CLI binaries, this module embeds all necessary functionality within Java itself, by following these steps:

1. Strip out the CLI interface from libprotobuf (to avoid spawning external processes).
2. Compile the modified libprotobuf into WebAssembly (.wasm) using wasi-sdk.
3. Translate the resulting WebAssembly into pure Java bytecode at build time using Chicory.
4. Use this generated Java dependency, which contains the full protoc capabilities (and plugin support), to perform gRPC code generation in-process on the JVM.

To enable gRPC code generation in your Quarkus project, add the dependency:

<dependency> <groupId>io.quarkiverse.grpc.zero</groupId> <artifactId>quarkus-grpc-zero</artifactId> <version>VERSION</version> </dependency>

If you are migrating from io.quarkus:quarkus-grpc, first exclude the original codegen dependency.

 <dependency> <groupId>io.quarkus</groupId> <artifactId>quarkus-grpc</artifactId> <exclusions> <exclusion> <groupId>io.quarkus</groupId> <artifactId>quarkus-grpc-codegen</artifactId> </exclusion> </exclusions> </dependency>

Also ensure your quarkus-maven-plugin configuration includes the generate-code goal:

<plugin> <groupId>io.quarkus</groupId> <artifactId>quarkus-maven-plugin</artifactId> <executions> <execution> <goals> <goal>build</goal> <goal>generate-code</goal> </goals> </execution> </executions> </plugin>

quarkus-grpc-zero supports the same configuration options as quarkus-grpc.

Additionally, you can skip code generation with:

-Dquarkus.zero.grpc.codegen.skip=true

Must be set at the Maven/JVM level — it does not work when placed in application.properties.

This project is building on the shoulders of giants. Special thanks to:

• wasilibs/go-protoc-gen-grpc-java – for prior work and invaluable help
• dylibso/chicory – for the Wasm compiler to Java Bytecode