Step Functions vs State Machines: Clearing Up the Confusion
When developers hear “AWS Step Functions,” they usually think of workflows in the cloud. But technically:
- Step Functions = the AWS service that orchestrates workflows.
- State Machine = the definition of the workflow itself, built in JSON using the Amazon States Language (ASL).
You can think of AWS Step Functions as the “engine,” and state machines as the “blueprints” that engine runs.
Why Developers Want to Run Step Functions Local
Running workflows only in AWS has drawbacks:
- Costs add up quickly if you’re testing frequently.
- Delays in deploying and monitoring slow down iteration.
- Surprise bills can pop up from a runaway workflow or misconfigured state machine.
That’s why many teams now ask: “How can I run Step Functions locally?”
How to Run Step Functions Locally with an Emulator
To run AWS Step Functions locally, you need an emulator or local runner that mimics the Step Functions service.
With a Step Functions local emulator, you can:
- Load your state machine definition on your laptop
- Execute and debug the workflow offline
- Test integrations with Lambda or API calls without deploying to AWS
This approach is often called “local Step Functions testing” or “Step Functions local execution.”
Local State Machine Testing vs Cloud Execution
When you run Step Functions local:
- Local Execution
- Fast iterations
- No cloud costs
- Ideal for debugging logic
- Cloud Execution
- Real AWS integrations
- Monitored in AWS Console
- Production-ready reliability
The smart approach is to start with local testing and only move to the AWS cloud once the workflow logic is solid.
Benefits of Running AWS Step Functions Locally
- Save Costs – Stop paying AWS fees every time you test.
- Debug Faster – Make changes and instantly re-run locally.
- Avoid Risk – No surprise 10x cloud bills from uncaught loops.
- Increase Collaboration – Share state machines in Git and let teammates run them local, without each needing cloud access.
Best Practices for Local Step Functions Development
- Keep state machine JSON in version control (Git).
- Validate with the Amazon States Language checker.
- Use mock data when Lambdas or external APIs aren’t available.
- Always do a final test in AWS Step Functions before going live.
The Bottom Line
The bottom line: AWS Step Functions is the service. State machines are the workflows inside it.
By learning how to run Step Functions local, you can cut costs, debug faster, and build workflows with confidence before pushing them into production.