---
title: "Consuming messages"
description: "Consuming messages — a normal Symfony Messenger handler, routed by message class; BabelQueue decodes the envelope and bridges retry + trace."
source: https://babelqueue.com/docs/symfony/1.x/consuming-messages/
updated: 2026-06-07T00:00:00.000Z
---

# Consuming messages

Consuming is a normal Messenger handler. The serializer decodes the inbound envelope,
uses the [URN → class map](/docs/symfony/1.x/configuration/#urn--message-class-map) to
rebuild your message via `fromBabelPayload()`, and Messenger routes it to the handler
for that class.

## A handler

```php
use Symfony\Component\Messenger\Attribute\AsMessageHandler;

#[AsMessageHandler]
final class OnOrderCreated
{
    public function __invoke(OrderCreated $message): void
    {
        // $message->orderId === 1042
    }
}
```

Run the worker exactly as you normally would:

```bash
php bin/console messenger:consume babel
```

## How it maps to Messenger

- **Routing** is Messenger's job: the decoded message class is routed to its handler.
  An inbound URN with no entry in the `messages` map cannot be rebuilt — keep the
  registry in sync with the URNs you consume.
- **Retry** bridges both ways: Messenger's `RedeliveryStamp` ⇄ the envelope's
  top-level `attempts`. Your existing Messenger retry strategy applies unchanged.
- **Tracing**: the inbound `trace_id` is attached as a `BabelTraceStamp`. With
  `babelqueue.messenger.trace_middleware` on the bus, any message a handler dispatches
  inherits that `trace_id`, so a whole chain of work stays in one trace.

## Cross-language

Because the wire format is the canonical envelope, a message your Symfony app consumes
may have been produced by **any** BabelQueue SDK — a Laravel app, a Go service, a
Python worker — and vice-versa. The URN is the only shared contract; no class is
shared across languages. See the [wire contract](/docs/spec/1.x/envelope/) and the
[cross-language example](/docs/examples/1.x/cross-language-redis/).