Event-driven architectures are at the heart of modern serverless systems. With Amazon EventBridge, developers can route events between services, trigger workflows, and build loosely coupled systems that scale effortlessly. The challenge has always been testing these event flows without deploying to AWS and incurring cost or delays.
With the latest Thrubit release, EventBridge support is now fully integrated into local Step Functions execution, allowing you to build, run, and debug event-driven workflows entirely on your machine.
What Is EventBridge in Step Functions
EventBridge integration in AWS Step Functions allows you to publish events directly from your workflows using the events:putEvents API. This makes it possible to trigger downstream services, fan out events, or integrate with external systems as part of your orchestration logic.
In a typical cloud workflow, testing this requires:
- Deploying your state machine
- Configuring EventBridge rules
- Monitoring events in AWS
- Paying for executions and event ingestion
Thrubit removes that friction by bringing EventBridge execution into your local development environment.
Full Local Support for events:putEvents
Thrubit now fully executes:
arn:aws:states:::events:putEvents
Task states locally, meaning your workflows behave exactly as they would in AWS without needing to deploy.
What this enables
- Test event publishing logic instantly
- Validate payload structure and transformations
- Debug workflows without waiting on cloud resources
- Eliminate AWS costs during development
Mock Mode: Instant Feedback Without AWS
By default, Thrubit runs EventBridge in Mock Mode, which means:
- No AWS credentials required
- No network calls made
- Instant responses for every event entry
Each event returns a simulated EventId, allowing your workflow to continue as if it were running in AWS.
This is ideal for:
- Rapid prototyping
- Offline development
- Training and demos
- Eliminating unexpected AWS charges
Live AWS Mode: Real Event Publishing When You Need It
When you’re ready to test against real infrastructure, you can disable Mock Mode and switch to Live AWS Mode.
In this mode:
- Events are sent to AWS EventBridge using your configured profile and region
- Responses include real EventIds
- Partial failures are surfaced per entry, just like in AWS
This allows you to validate real integrations without changing your workflow definition.
Start free. No AWS account needed.
ZERO AWS costs.
Download Thrubit and run your first state machine locally in under five minutes. No cloud setup, no IAM policies, no waiting.
waitForTaskToken Handling
Thrubit recognizes waitForTaskToken patterns in EventBridge states and handles them intelligently.
Instead of blocking execution:
- The event is sent immediately
- The state completes without hanging
- A warning is logged to indicate the behavior
This mirrors how Thrubit treats other callback patterns locally, ensuring workflows remain testable without introducing artificial delays.
Automatic Detail Serialization
EventBridge expects the Detail field to be a JSON string. In real AWS Step Functions, objects are automatically serialized.
Thrubit replicates this behavior by:
- Converting object-based
Detailvalues into JSON strings automatically - Ensuring parity between local and cloud execution
This prevents subtle bugs that often appear only after deployment.
Multi-Entry Support
Thrubit fully supports both:
- Single event entries
- Arrays of entries (
Entries[])
This means you can test:
- Bulk event publishing
- Fan-out scenarios
- Complex event batching logic
All without leaving your local environment.
ResultSelector Support
EventBridge responses can be reshaped using ResultSelector in your state machine definition.
Thrubit applies these transformations locally, allowing you to:
- Validate output structure
- Test downstream state dependencies
- Ensure JSONPath mappings behave correctly
Why This Matters for Developers
Before this release, testing EventBridge workflows meant constant deployment cycles, cloud costs, and limited visibility into execution.
With Thrubit, you can now:
- Run Step Functions locally with real Lambda execution
- Publish and inspect EventBridge events without AWS
- Debug visually and iterate instantly
- Catch issues before they reach production
This dramatically improves development speed and reduces risk.
Build Event-Driven Workflows Without the Cloud Bottleneck
EventBridge is a powerful tool for building scalable, decoupled systems. But until now, it has been difficult to test locally in a way that truly reflects production behavior.
Thrubit changes that.
You can now design, execute, and debug event-driven Step Functions workflows with confidence, knowing that what you see locally will match what happens in AWS.
Start Running EventBridge Workflows Locally
If you are building event-driven architectures with AWS Step Functions, local testing is no longer optional. It is a competitive advantage.
Thrubit gives you:
- Zero-cost development cycles
- Faster iteration
- Full visibility into execution
- Confidence in deployment
Start building smarter workflows by running EventBridge locally today.