Skip to content


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?

Latest commit


Git stats


Failed to load latest commit information.
Latest commit message
Commit time

Reactive Relational Database Connectivity Proxy Framework Java CI with Maven Maven Central

This project contains the proxy framework of the R2DBC SPI. R2DBC is a Reactive Foundation project.

Code of Conduct

This project is governed by the R2DBC Code of Conduct. By participating, you are expected to uphold this code of conduct. Please report unacceptable behavior to

Maven configuration

Artifacts can be found on Maven Central:


If you'd rather like the latest snapshots of the upcoming major version, use our Maven snapshot repository and declare the appropriate dependency version.


  <name>Sonatype OSS Snapshot Repository</name>

R2DBC SPI versions

1.0.x, 1.1.x 1.0.x
0.9.x 0.9.x
0.8.x 0.8.x


Getting Started

Here shows how to create a proxy ConnectionFactory.

URL Connection Factory Discovery

ConnectionFactory connectionFactory = ConnectionFactories.get("r2dbc:proxy:<driver>//<host>:<port>>/<database>[?proxyListener=<fqdn>]");

Sample URLs:

# with driver

# with pooling

Programmatic Connection Factory Discovery

ConnectionFactory connectionFactory = ConnectionFactories.get(ConnectionFactoryOptions.builder()
   .option(DRIVER, "proxy")
   .option(PROTOCOL, "postgresql")

Mono<Connection> connection = connectionFactory.create();

Supported Connection Factory Discovery options:

Option Description
driver Must be proxy
protocol Delegating connection factory driver
proxyListener Comma separated list of fully qualified proxy listener class names (Optional)

When programmatically ConnectionFactoryOptions are constructed, proxyListener option allows following values:

  • Comma separated list of fully qualified proxy listener class names
  • Proxy listener class
  • Proxy listener instance
  • Collection of above

Programmatic creation with ProxyConnectionFactory

ConnectionFactory original = ...

ConnectionFactory connectionFactory = ProxyConnectionFactory.builder(original)
    .onAfterQuery(queryInfo ->
        ...  // after query callback logic
    .onBeforeMethod(methodInfo ->
        ...  // before method callback logic
    .listener(...)  // add listener

Publisher<? extends Connection> connectionPublisher = connectionFactory.create();

// Alternative: Creating a Mono using Project Reactor
Mono<Connection> connectionMono = Mono.from(connectionFactory.create());


r2dbc-proxy-samples repository contains sample listener implementations.

Getting Help

Having trouble with R2DBC? We'd love to help!

Reporting Issues

R2DBC uses GitHub as issue tracking system to record bugs and feature requests. If you want to raise an issue, please follow the recommendations below:

  • Before you log a bug, please search the issue tracker to see if someone has already reported the problem.
  • If the issue doesn't already exist, create a new issue.
  • Please provide as much information as possible with the issue report, we like to know the version of R2DBC Proxy that you are using and JVM version.
  • If you need to paste code, or include a stack trace use Markdown ``` escapes before and after your text.
  • If possible try to create a test-case or project that replicates the issue. Attach a link to your code or a compressed file containing your code.

Building from Source

You don't need to build from source to use R2DBC Proxy (binaries in Maven Central), but if you want to try out the latest and greatest, R2DBC Proxy can be easily built with the maven wrapper. You also need JDK 1.8 and Docker to run integration tests.

 $ ./mvnw clean install

If you want to build with the regular mvn command, you will need Maven v3.5.0 or above.

Also see CONTRIBUTING.adoc if you wish to submit pull requests. Commits require Signed-off-by (git commit -s) to ensure Developer Certificate of Origin.

Building the documentation

Building the documentation uses maven asciidoctor plugin.

 $ ./mvnw clean exec:java@generate-micrometer-docs asciidoctor:process-asciidoc

Staging to Maven Central

To stage a release to Maven Central, you need to create a release tag (release version) that contains the desired state and version numbers (mvn versions:set versions:commit -q -o -DgenerateBackupPoms=false -DnewVersion=x.y.z.(RELEASE|Mnnn|RCnnn) and force-push it to the release-0.x branch. This push will trigger a Maven staging build (see


This project is released under version 2.0 of the Apache License.