October 6th, 2025

New this release:

• 🎉 (server, smithy-rs#4321, @jasgin) Adds the custom traits @validationException, @validationMessage, @validationFieldList, @validationFieldName, and @validationFieldMessage
  for defining custom validation exceptions.

Contributors
Thank you for your contributions! ❤

• @jasgin (smithy-rs#4321)

October 2nd, 2025

New this release:

• 🐛 (server) Fix bug where servers rejected application/vnd.amazon.evenstream ACCEPT header for RPCv2Cbor

  This change allows this header while also allowing application/cbor for backwards compatibility.

October 1st, 2025

New this release:

• 🎉 (client, smithy-rs#4299, @greenwoodcm) Added a new then_compute_output to aws-smithy-mocks rule builder that allows using the input type when computing a mocked response, e.g.

  // Return a computed output based on the input
  let compute_rule = mock!(Client::get_object)
      .then_compute_output(|req| {
          let key = req.key().unwrap_or("unknown");
          GetObjectOutput::builder()
              .body(ByteStream::from_static(format!("content for {}", key).as_bytes()))
              .build()
      });

• 🐛 (client, smithy-rs#4226, @haydenbaker) Fixed problematic assertion on HttpApiKeyAuthTrait scheme, which was causing client-codegen to fail when the correct settings for api-key based auth were set.

Contributors
Thank you for your contributions! ❤

• @greenwoodcm (smithy-rs#4299)
• @haydenbaker (smithy-rs#4226)

September 10th, 2025

New this release:

• 🐛 (client, smithy-rs#4274) The HickoryDnsResolver and TokioDnsResolver were not Clone making it impossible to use them in the http_client builder's build_with_resolver method.

August 28th, 2025

New this release:

• 🎉 (client, smithy-rs#4274) Add a new crate, aws-smithy-dns that contains a HickoryDnsResolver. This wraps a hickory_resolver::Resolver and provides some minimal configuration options (timeouts, retries, etc.) Instructions for overriding the DNS resolver on your HTTP client can be found in our documentation at https://docs.aws.amazon.com/sdk-for-rust/latest/dg/http.html#overrideDns
• 🐛 (client, smithy-rs#4282) Set the pool_timer for the default Hyper client. This is required to allow the pool_idle_timeout to work. Now idle connections will be released by the pool after 90 seconds.
• (client, smithy-rs#4263) Make TokenBucket and ClientRateLimiter configurable through RetryPartition.

August 18th, 2025

New this release:

• 🎉 (client, aws-sdk-rust#169) Add support for proxy environment variables (HTTP_PROXY, HTTPS_PROXY, ALL_PROXY, NO_PROXY). Service clients will now automatically respect these proxy environment variables on the latest BehaviorVersion. Older behavior versions do not automatically detect these environment variables and will require manually building a aws_smithy_http_client::Connector` with a proxy config explicitly set to use this feature.
• 🎉 (client, @WillChilds-Klein) Enable rustls post-quantum by default.
• (client) fix aws-smithy-eventstream feature derive-arbitrary on arbitrary >= 1.4.2

Contributors
Thank you for your contributions! ❤

• @WillChilds-Klein

August 13th, 2025

New this release:

• 🐛 (client) pin crc-fast to <1.4 to workaround SIGILL

August 11th, 2025

New this release:

• 🎉 (client, smithy-rs#4208) Add the ability to insert hints.mostly-unused = true in Cargo.toml. Enable this hint for the below crates:

  • aws-sdk-cloudformation
  • aws-sdk-dynamodb
  • aws-sdk-ec2
  • aws-sdk-s3
  • aws-sdk-sns
  • aws-sdk-sqs
  • aws-sdk-ssm
  • aws-sdk-sts

  See more information about this hint at https://blog.rust-lang.org/inside-rust/2025/07/15/call-for-testing-hint-mostly-unused/

• 🎉 (client, smithy-rs#4208, @joshtriplett) Enable hints.mostly-unused = true for aws-sdk-lambda (taking a release
  build from 57s to 40s) and aws-sdk-rds (taking a release build from 1m34s to
  49s).

Contributors
Thank you for your contributions! ❤

• @joshtriplett (smithy-rs#4208)

August 4th, 2025

New this release:

• 🎉 (all, @Dorenavant) Add EnumSection to allow decorators to modify enum member attributes
• 🐛 (client, smithy-rs#4227) Fix canonical request sort order

Contributors
Thank you for your contributions! ❤

• @Dorenavant

July 25th, 2025

New this release:

• 🐛 (client, smithy-rs#4232) Add fallback equality on no auth AuthSchemeId for backward compatibility, treating AuthSchemeId::from("no_auth") (legacy) and AuthSchemeId::from("noAuth") (updated) as equivalent.