AWS Lambda Durable Execution SDK for .NET hits GA
C# developers can now build long-running, checkpointed workflows directly in Lambda without external orchestration services.
Can .NET developers build long-running workflows directly in AWS Lambda?
Yes. AWS announced general availability of the Lambda Durable Execution SDK for .NET on July 23, 2026. The SDK lets C# developers write multi-step, stateful workflows inside Lambda functions without wiring up a separate orchestration service or hand-rolling progress tracking.
What problems does this solve?
Standard Lambda functions are stateless and short-lived, which makes them awkward for workflows that span minutes, hours, or days. Developers working on payment pipelines, AI agent orchestration, or human-in-the-loop approval flows have historically had to reach for services like Step Functions or build custom state management.
The durable execution model changes that by automatically checkpointing progress at each step. If a function is waiting on an external event, it can pause for up to a year without consuming compute resources, then resume where it left off.
What does the SDK actually include?
AWS describes four core capabilities in the SDK:
- Steps for tracking progress through multi-stage workflows
- Callback integration to handle human-in-the-loop and agent-in-the-loop patterns
- Durable invocation for reliable chaining between Lambda functions
- Waits that suspend execution efficiently while the function is idle
The SDK is distributed through NuGet, so it drops into existing .NET toolchains without additional setup. AWS also ships a local testing emulator alongside the SDK, letting teams develop and debug workflows on their own machines before pushing to production.
How do you get started?
Installing the package follows standard NuGet conventions:
dotnet add package Amazon.Lambda.DurableExecution
From there, developers can reference the Lambda durable functions developer guide for workflow patterns and the NuGet listing for package details. Regional availability and pricing are listed on the AWS Regional Services List and Lambda pricing page, respectively.
Who is the target audience?
The announcement is aimed squarely at C# developers already using Lambda who need workflows that outlast a single invocation. Specific use cases called out by AWS include payment processing pipelines, AI agent orchestration, and approval workflows where a human or another agent must act before execution continues.
What is the broader context?
The .NET SDK joins what AWS calls the Lambda durable functions programming model, which extends Lambda's existing event-driven approach rather than replacing it. By framing durable execution as an extension of familiar Lambda concepts, AWS appears to be targeting teams that want workflow durability without adopting a distinct orchestration paradigm.
The local emulator is a notable inclusion for developer experience. Testing stateful, long-running workflows has traditionally been difficult in serverless environments, and an emulator that runs locally lowers the iteration cost before a workflow reaches production.