AWS Protocols Overview

NSmithy’s AWS protocol support exists primarily as a proof of concept — a vehicle for validating the generator’s protocol abstraction, codec layer, and conformance test infrastructure against real AWS protocol definitions. This is especially true for aws.protocols#restXml and the AWS JSON protocols.

AWS restJson1 is the exception — see below.

(smithy.protocols#rpcv2Cbor is a Smithy-standard binary protocol, not AWS-specific; it is documented as a top-level protocol rather than under this AWS section.)

Use the Official AWS SDK for .NET Instead

If your goal is to call AWS services in production with restXml or AWS JSON, you should use the AWS SDK for .NET instead:

• It is officially supported and maintained by AWS.
• It covers the full breadth of AWS services.
• It includes authentication (SigV4/SigV4a), retries, endpoint resolution, pagination helpers, and presigned URLs.

AWS restJson1 Is Different

aws.protocols#restJson1 is not AWS-specific in practice — it is a well-defined REST/JSON wire format usable by any HTTP service, whether or not it runs on AWS. Many teams use it to define internal or public APIs that follow the same protocol as AWS services.

For AWS restJson1, NSmithy targets more than proof-of-concept use:

• Non-AWS services — generated clients and servers work today and are a reasonable choice for services modelled with restJson1 outside of AWS.
• AWS services in production — the goal is for NSmithy-generated restJson1 clients to be usable against real AWS services. Explicit SigV4 signing exists in early preview, but AWS SDK-style endpoint resolution, credential chains, retries, and pagination helpers are not there yet.

Until those pieces exist, use the official SDK when targeting AWS directly.

AWS SigV4 Is Early Preview

NSmithy.Aws includes explicit SigV4 signing through AwsSigV4AuthScheme. Callers provide the endpoint, signing service name, region, and credentials provider. This is enough for LocalStack examples and narrow smoke tests, but it is not a production AWS auth stack.

See Authentication for configuration details and current limitations.

AWS JSON Is Client-Only

NSmithy includes early client runtime support for aws.protocols#awsJson1_1 and aws.protocols#awsJson1_0. The current conformance project exercises an initial awsJson1_1 slice: target/header construction, empty input/output behavior, special floating-point values, and client-side error discrimination.

There is no AWS JSON server generation, and production AWS concerns such as AWS SDK-style credential resolution, endpoint resolution, retries, and pagination helpers are still outside the generated client.