sosw — bootstrap AWS Lambda functions

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sosw is a Python framework for bootstrapping AWS Lambda functions.

It gives every Lambda in your account the same production-grade skeleton in a dozen lines of code:

  • Processor — a base class with layered configuration (code defaults + DynamoDB / SSM overrides), automatic initialization of AWS clients, statistics counters and a uniform entry point;

  • warm start — the generated lambda_handler caches the initialized Processor for the lifetime of the Lambda container, so warm invocations skip all the initialization work (see Warm start);

  • LambdaApi — a declarative router base class for Lambdas behind API Gateway (routes, Cognito claims, CORS, uniform JSON error envelopes);

  • durable functions support — an optional wrapper integrating the AWS Lambda Durable Execution SDK (pip install sosw[durable]);

  • components and helpers — battle-tested middleware for DynamoDB, SNS, configuration sources, SigV4-signed requests, sibling invocations and a large helpers library.

The only mandatory runtime dependency is boto3. Python 3.12 – 3.14 are supported.

Note

Upgrading from the 0.7.x line? Read the migration guide first — the major release removed a whole layer of the package. The documentation of the previous versions is preserved: 0.7.51 docs.

Install it and build your first function in minutes:

pip install sosw

Note

Please pronounce sosw correctly: /ˈsɔːsəʊ/

Contents:

Previous versions

  • sosw 0.7.51 documentation — the archived documentation of the 0.7.x line (covering everything this major release removed from the package).

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