---
title: "Spring Boot adapter"
description: "The babelqueue-spring Spring Boot adapter: a Spring AMQP MessageConverter, an injectable publisher and auto-configuration for RabbitTemplate."
source: https://babelqueue.com/docs/babelqueue-java/1.x/spring/
updated: 2026-10-13T00:00:00.000Z
---

# Spring Boot adapter

`com.babelqueue:babelqueue-spring` plugs the Java core into **Spring AMQP**. Its
auto-configuration registers a `MessageConverter` that encodes/decodes the canonical
envelope, so Boot wires it into both the `RabbitTemplate` (producing) and your
`@RabbitListener` containers (consuming) — no manual setup.

## Install

Maven:

```xml
<dependency>
    <groupId>com.babelqueue</groupId>
    <artifactId>babelqueue-spring</artifactId>
    <version>1.1.1</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-amqp</artifactId>
</dependency>
```

Gradle:

```kotlin
implementation("com.babelqueue:babelqueue-spring:1.1.1")
implementation("org.springframework.boot:spring-boot-starter-amqp")
```

Requirements: **Spring Boot 3**, **Java 17+**, RabbitMQ. The core
(`babelqueue-core`) comes transitively.

## Configuration

```yaml
# application.yaml
babelqueue:
  default-queue: orders   # written to meta.queue; used when no queue is given
```

Auto-configuration exposes one `MessageConverter` bean (`BabelQueueMessageConverter`)
and a `BabelQueuePublisher`. Both **back off** if your app defines its own. Boot's
RabbitMQ auto-config injects the single converter into the `RabbitTemplate` and the
default listener container factory.

## Produce

Inject `BabelQueuePublisher`. Its `publish(...)` methods return the message `meta.id`:

```java
import com.babelqueue.spring.BabelQueuePublisher;
import java.util.Map;
import org.springframework.stereotype.Service;

@Service
class Orders {
    private final BabelQueuePublisher babelQueue;

    Orders(BabelQueuePublisher babelQueue) {
        this.babelQueue = babelQueue;
    }

    void create() {
        babelQueue.publish("urn:babel:orders:created", Map.of("order_id", 1042L), "orders");
    }
}
```

Available overloads: `publish(urn, data)`, `publish(urn, data, queue)`,
`publish(urn, data, queue, traceId)`, and — for a typed message implementing
`com.babelqueue.PolyglotMessage` — `publish(message)` / `publish(message, queue)`.

Each message carries the contract AMQP properties: `type` = URN, `correlationId` =
`trace_id`, `messageId` = `meta.id`, plus `x-attempts` / `x-schema-version` /
`x-source-lang` headers, `application/json` and persistent delivery.

## Consume

A normal `@RabbitListener` receives a decoded core `Envelope`; route by URN with
`EnvelopeCodec.urn(...)`:

```java
import com.babelqueue.Envelope;
import com.babelqueue.EnvelopeCodec;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.stereotype.Component;

@Component
class OrderListener {
    @RabbitListener(queues = "orders")
    void onMessage(Envelope envelope) {
        if ("urn:babel:orders:created".equals(EnvelopeCodec.urn(envelope))) {
            var orderId = envelope.data().get("order_id");
            // ... use envelope.traceId(), envelope.data()
        }
    }
}
```

Non-conformant messages (missing URN, unsupported `meta.schema_version`, blank
`trace_id`, or missing `data`) are rejected by the converter — route them to a
dead-letter exchange the usual Spring AMQP way.

Because the wire format is the [canonical envelope](/docs/spec/1.x/envelope/), a
message your Spring app consumes may have been produced by any BabelQueue SDK, and
vice-versa.