Customizing State Machines

Sylius uses Symfony's Workflow Component to manage business processes such as order checkout and payment flows. These workflows (also called state machines) define the states an entity can be in and how transitions between these states happen.

Sylius provides predefined workflows, but many projects require customizations. This guide will walk you through how to find, extend, and modify these workflows in a clear, step-by-step way.

To get an overview of how state machines are structured and used across Sylius resources (like orders, shipments, and payments), refer to the State Machine Architecture Guide in the Sylius Book.

How to find the desired state machine to customize?

Locate the Workflow Graph

Each workflow in Sylius is defined with a unique graph constant. For example, the order checkout workflow uses:

Sylius\Component\Core\OrderCheckoutTransitions::GRAPH

Explore Defined Workflows

You can list all configured Sylius workflows using Symfony’s console tool:

php bin/console debug:config framework workflows | grep sylius_

This will display all defined workflows, their states (places), and transitions.

Best Practice: Always reference workflows, states, and transitions using constants (e.g., OrderCheckoutTransitions::GRAPH) rather than raw strings. This ensures better maintainability and fewer typos. You can find all the workflow constants here.

Extending the existing workflows

Let’s assume you want to add a new state and a custom transition to the order checkout workflow.

Add a New State

Update your config/packages/_sylius.yaml:

framework:
    workflows:
        !php/const Sylius\Component\Core\OrderCheckoutTransitions::GRAPH:
            places:
                - 'custom_state'

Add a New Transition

Now let’s create a transition from an existing state to the new custom_state:

framework:
    workflows:
        !php/const Sylius\Component\Core\OrderCheckoutTransitions::GRAPH:
            transitions:
                custom_transition:
                    from: !php/const Sylius\Component\Core\OrderCheckoutStates::STATE_ADDRESSED
                    to: 'custom_state'

You can now create custom logic triggered by this transition if needed.

Result:

The workflow before:

The workflow after:

To learn how to generate graphs like the ones used in this guide, visit this site.

Removing Transitions and States

Sometimes, you need to remove default transitions or states. This requires a compiler pass to alter Symfony's service container.

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Example 1: Remove the skip_shipping Transition

Step 1: Create RemoveSkipShippingTransitionCompilerPass.php

<?php

namespace App\DependencyInjection\Compiler;

use Sylius\Component\Core\OrderCheckoutTransitions;
use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;

final class RemoveSkipShippingTransitionCompilerPass implements CompilerPassInterface
{
    public function process(ContainerBuilder $container): void
    {
        $graph = OrderCheckoutTransitions::GRAPH;
        $transitionToRemove = OrderCheckoutTransitions::TRANSITION_SKIP_SHIPPING;

        $definition = $container->getDefinition(sprintf('state_machine.%s.definition', $graph));
        $transitions = $definition->getArgument(1);

        foreach ($transitions as $i => $ref) {
            $transitionDef = $container->getDefinition((string) $ref);
            if ($transitionDef->getArgument(0) === $transitionToRemove) {
                unset($transitions[$i]);
                break;
            }
        }

        $definition->replaceArgument(1, array_values($transitions));
    }
}

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Example 2: Remove the shipping_skipped State

Step 2: Create RemoveShippingSkippedStateCompilerPass.php

<?php

namespace App\DependencyInjection\Compiler;

use Sylius\Component\Core\OrderCheckoutStates;
use Sylius\Component\Core\OrderCheckoutTransitions;
use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;

final class RemoveShippingSkippedStateCompilerPass implements CompilerPassInterface
{
    public function process(ContainerBuilder $container): void
    {
        $graph = OrderCheckoutTransitions::GRAPH;
        $stateToRemove = OrderCheckoutStates::STATE_SHIPPING_SKIPPED;

        $definition = $container->getDefinition(sprintf('state_machine.%s.definition', $graph));
        $places = $definition->getArgument(0);
        $transitions = $definition->getArgument(1);

        $placeKey = array_search($stateToRemove, $places, true);
        if ($placeKey !== false) {
            unset($places[$placeKey]);
            $places = array_values($places);
        }

        foreach ($transitions as $i => $ref) {
            $transitionDef = $container->getDefinition((string) $ref);
            $from = (array) $transitionDef->getArgument(1);
            $to = $transitionDef->getArgument(2);

            if (in_array($stateToRemove, $from, true) || $to === $stateToRemove) {
                unset($transitions[$i]);
            }
        }

        $definition->replaceArgument(0, $places);
        $definition->replaceArgument(1, array_values($transitions));
    }
}

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Register Compiler Passes

In your Kernel.php:

protected function build(ContainerBuilder $container): void
{
    $container->addCompilerPass(new \App\DependencyInjection\Compiler\RemoveSkipShippingTransitionCompilerPass());
    $container->addCompilerPass(new \App\DependencyInjection\Compiler\RemoveShippingSkippedStateCompilerPass());
}

Result:

Adding Workflow Callbacks

You can hook into workflow events using Symfony event listeners.

Example: Send an Email After Order Completion

Create a listener class:

namespace App\EventListener\Workflow\OrderCheckout;

use Symfony\Component\Workflow\Event\CompletedEvent;

final class SendEmailWithGiftCodeAfterOrderCompletionListener
{
    public function __invoke(CompletedEvent $event): void
    {
        // Send gift email
    }
}

Register the service:

services:
    app.listener.workflow.order_checkout.send_email_with_gift:
        class: App\EventListener\Workflow\OrderCheckout\SendEmailWithGiftCodeAfterOrderCompletionListener
        tags:
            - { name: kernel.event_listener, event: workflow.sylius_order_checkout.completed.complete, priority: 100 }

Overriding Existing Workflow Listeners

To customize existing logic, redefine the listener service.

Example: Customize Shipping State Resolver

services:
    sylius.listener.workflow.order_checkout.resolve_order_shipping_state:
        class: App\EventListener\Workflow\OrderCheckout\ResolveOrderShippingStateListener
        tags:
            - { name: kernel.event_listener, event: workflow.sylius_order_checkout.completed.complete, priority: 100 }

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🔧 Debug Your Workflow Setup

Use this command to see what listeners are registered for a workflow event:

php bin/console debug:event workflow.sylius_order_checkout.completed.complete

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Optional: Legacy Winzou State Machine

If you're migrating from Sylius 1.x or using the Winzou State Machine, refer to its documentation for configuring transitions differently or to Sylius 1.x documentation.