AWS Step Functions provides serverless orchestration for modern applications. Orchestration centrally manages a workflow by breaking it into multiple steps, adding flow logic, and tracking the inputs and outputs between the steps. As your applications execute, Step Functions maintains application state, tracking exactly which workflow step your application is in, and stores an event log of data that is passed between application components. That means that if networks fail or components hang, your application can pick up right where it left off.
Application development is faster and more intuitive with Step Functions, because you can define and manage the workflow of your application independently from its business logic. Making changes to one does not affect the other. You can easily update and modify workflows in one place, without having to struggle with managing, monitoring and maintaining multiple point-to-point integrations. Step Functions frees your functions and containers from excess code, so your applications are faster to write, more resilient, and easier to maintain.
Using Step Functions, you define your workflows as state machines, which transform complex code into easy to understand statements and diagrams. Building apps, and confirming that they are implementing your desired functionality, is quicker and easier. Read more about how Step Functions works.
Built-in service primitives
Step Functions provides ready-made steps for your workflow called states that implement basic service primitives for you, which means you can remove that logic from your application. States can pass data to other states and microservices, handle exceptions, add timeouts, make decisions, execute multiple paths in parallel, and more. Learn more about states.
AWS service integrations
Using Step Functions service tasks, you can configure your Step Functions workflow to call other AWS services. This includes compute services (AWS Lambda, Amazon ECS, AWS Fargate), database services (Amazon DynamoDB), messaging services (Amazon SNS and Amazon SQS), data processing services (AWS Batch and AWS Glue), and machine learning services (Amazon SageMaker). Learn more about service tasks.
Coordination of distributed components
Step Functions can coordinate any application that can make an HTTPS connection, regardless of where it is hosted—for example, on Amazon EC2 instances, mobile devices, or on-premises servers. Using Step Functions, you can quickly create distributed applications that leverage AWS services as well as your own microservices. Learn more about activity tasks.
AWS Step Functions coordinates your existing Lambda functions and microservices into robust applications, and lets you quickly rewire them into new compositions. The tasks in your workflow can run anywhere, including on instances, containers, functions, and mobile devices. Learn how to reuse existing application components.
Step Functions keeps the logic of your application strictly separated from the implementation of your application. You can add, move, swap, and reorder steps without having to make changes to your business logic. Through this separation of concerns, your workflows gain modularity, simplified maintenance, scalability, and code reuse.
Step Functions maintains the state of your application during execution, including tracking what step of execution it is in, and storing data that is moving between the steps of your workflow. This means you don't have to manage state yourself with data stores or by building complex state management into all of your tasks.
Built-in error handling
AWS Step Functions automatically handles errors and exceptions with built-in try/catch and retry, whether the task takes seconds or months to complete. You can automatically retry failed or timed-out tasks, respond differently to different types of errors, and recover gracefully by falling back to designated cleanup and recovery code. Learn more about Step Functions error handling and how you can handle error conditions using a state machine.
History of each execution
AWS Step Functions delivers real-time diagnostics and dashboards, integrates with Amazon CloudWatch and AWS CloudTrail, and logs every execution, including overall state, failed steps, inputs, and outputs. If things go wrong, you can quickly identify not only where, but why, and quickly troubleshoot and remediate failures. Learn more about Step Functions monitoring and logging.
Launching an application is as simple as pressing a button, then watching the steps execute visually, so you can quickly verify that everything is operating in order – and as expected. The console clearly highlights errors, so you can quickly pinpoint their root-cause, and troubleshoot issues.
AWS Step Functions has built-in fault tolerance and maintains service capacity across multiple Availability Zones in each region to protect applications against individual machine or data center failures. This helps ensure high availability for both the service itself and for the application workflow it operates.
AWS Step Functions automatically scales the operations and underlying compute to run the steps of your application for you in response to changing workloads. Step Functions scales automatically to help ensure the performance of your application workflow remains consistent as the frequency of requests increases.
Pay per use
With AWS Step Functions, you pay for each transition from one state to the next. Billing is metered by state transition, and you do not pay for idle time, regardless of how long each state persists (up to one year). This keeps Step Functions cost-effective as you scale from a few executions to tens of millions. Learn more about Step Functions pricing.