---
title: "Broker transports"
description: "Run BabelQueue over any Symfony Messenger transport — built-in (AMQP, Redis) or third-party (Kafka, AMQP 1.0) — with the babelqueue.messenger.serializer. Interop is body-authoritative, so no broker-specific BabelQueue transport is needed."
source: https://babelqueue.com/docs/symfony/1.x/broker-transports/
updated: 2026-06-14T00:00:00.000Z
---

# Broker transports

The BabelQueue adapter is a Messenger **serializer**, not a transport. It encodes and
decodes the [canonical envelope](/docs/spec/1.x/envelope/) on whatever Messenger
transport you configure — so **Symfony interoperates over any broker Messenger can
reach**, and there is no broker-specific "BabelQueue transport" to install. Point a
transport at the serializer and you are done:

```yaml
# config/packages/messenger.yaml
framework:
  messenger:
    transports:
      babel:
        dsn: '%env(MESSENGER_TRANSPORT_DSN)%'
        serializer: 'babelqueue.messenger.serializer'
```

## Built-in transports (RabbitMQ, Redis)

Messenger ships first-party transports for **AMQP** (RabbitMQ —
[§2](/docs/spec/1.x/broker-bindings/)) and **Redis**
([§1](/docs/spec/1.x/broker-bindings/)). Set the DSN and the serializer; a Go / Python /
Laravel / … consumer on the same broker reads the byte-identical envelope:

```dotenv
# RabbitMQ
MESSENGER_TRANSPORT_DSN=amqp://guest:guest@localhost:5672/%2f/orders
# …or Redis
MESSENGER_TRANSPORT_DSN=redis://localhost:6379/messages
```

These are the GA path for Symfony; see the [broker setup recipes](/docs/spec/1.x/broker-recipes/)
for the cross-language pairings.

## Beyond the built-ins (Kafka, Pulsar, Artemis/AMQP 1.0)

Messenger has **no first-party transport** for Kafka ([§6](/docs/spec/1.x/broker-bindings/)),
Pulsar ([§5](/docs/spec/1.x/broker-bindings/)) or Artemis over AMQP 1.0
([§7](/docs/spec/1.x/broker-bindings/)). You do **not** need a BabelQueue-specific transport
for them — use a **third-party Messenger transport** for that broker and wire the same
`babelqueue.messenger.serializer` onto it. The serializer puts the canonical envelope in the
message **body**, so the wire format is identical regardless of which transport carries it.

```yaml
framework:
  messenger:
    transports:
      babel-kafka:
        dsn: '%env(KAFKA_TRANSPORT_DSN)%'   # from a community Kafka Messenger transport
        serializer: 'babelqueue.messenger.serializer'
```

> **Interop is body-authoritative.** A cross-language consumer routes on the body's `job`
> URN, which is always present — so a Symfony-produced message is consumed correctly on any
> of these brokers even when the transport doesn't reproduce the binding's *native* property
> projection (AMQP `type`, Pulsar/Kafka `bq-job` header, …). The serializer also emits the
> cross-broker `bq-*` headers (`bq-job`, `bq-trace-id`, `bq-message-id`, `bq-schema-version`,
> `bq-source-lang`, `bq-attempts`); a transport that maps serializer headers onto native
> broker headers (e.g. a Kafka Messenger transport → Kafka record headers) carries them
> through, so consumers can also route without decoding the body.

## When you want the native projection

If you need the **exact native projection** of a binding (so non-PHP consumers route on the
broker-native field — AMQP `type`, SQS `MessageAttributes`, the Pulsar/Kafka `bq-` headers,
the Artemis STOMP framing), reach for the framework-less
[`babelqueue/php-sdk`](/docs/php-sdk/1.x/transports/) transports directly instead of going
through Messenger:

| Broker | Native produce / consume on `php-sdk` |
| :--- | :--- |
| Apache Kafka (§6) | `KafkaTransport` (produce) · `KafkaConsumer` + retry topics (consume) |
| Apache Pulsar (§5) | `PulsarTransport` (produce) · `PulsarConsumer` (consume) |
| Apache Artemis (§7) | `StompTransport` (produce); Laravel ships the `babelqueue-artemis` consume driver |
| Amazon SQS (§3) | `SqsTransport` |

These emit the binding's native `bq-`/property projection verbatim. The envelope is the same
`schema_version: 1` either way — Messenger-serializer or framework-less transport is purely a
wiring choice.