@smithy/core breaking changes

3.38.0

1 breaking change, first published November 3, 2026.

• Signature changed protocols:getHttpHandlerExtensionConfiguration
  Was const getHttpHandlerExtensionConfiguration: <HandlerConfig extends {logger?: Logger;}>(runtimeConfig: HttpHandlerExtensionConfigType<HandlerConfig> & {logger?: Logger;}) => {setHttpHandler(handler: HttpHandler<HandlerConfig>): void... npmjs.com

3.37.0

5 breaking changes, first published October 26, 2026.

• Removed cbor:SmithyRpcV2CborProtocol.constructor
  new SmithyRpcV2CborProtocol() was removed in @smithy/core 3.37.0 npmjs.com
• Removed protocols:SmithyRpcV2JsonProtocol.constructor
  new SmithyRpcV2JsonProtocol() was removed in @smithy/core 3.37.0 npmjs.com
• Behavior changed
  Responses with a 2xx status other than 200 (such as 201 or 204) are now raised as errors by the Smithy RPC v2 JSON and CBOR client protocols. Code that relied on those statuses succeeding must handle the error instead. github.com
• Signature changed cbor:SmithyRpcV2CborProtocol
  Was class SmithyRpcV2CborProtocol extends RpcProtocol; now class SmithyRpcV2CborProtocol extends AbstractRpcV2Protocol. npmjs.com
• Signature changed protocols:SmithyRpcV2JsonProtocol
  Was class SmithyRpcV2JsonProtocol extends RpcProtocol; now class SmithyRpcV2JsonProtocol extends AbstractRpcV2Protocol. npmjs.com

3.35.0

3 breaking changes, first published September 22, 2026.

• Behavior changed
  Responses with status code 500 from CBOR services are now classified as server faults. Code that handled these responses as a different error category may need to be updated. github.com
• Behavior changed
  Error identification for CBOR responses no longer falls back to the code property in the response body. Code that relied on that fallback to identify errors must check for other error fields. github.com
• Signature changed client:Client.send
  Was send<InputType extends ClientInput, OutputType extends ClientOutput>(command: Command<ClientInput, InputType, ClientOutput, OutputType, SmithyResolvedConfiguration<HandlerOptions>>, options: HandlerOptions, cb: (err: any, data?... npmjs.com

3.33.1

11 breaking changes, first published August 15, 2026.

• Signature changed client:getDefaultClientConfiguration
  Was const getDefaultClientConfiguration: (runtimeConfig: DefaultExtensionRuntimeConfigType) => {addChecksumAlgorithm(algo: import("@smithy/types").ChecksumAlgorithm): void; checksumAlgorithms()... npmjs.com
• Signature changed event-streams:EventStreamSerde.deserializeEventStream
  Was deserializeEventStream({response, responseSchema, initialResponseContainer}: {response: IHttpResponse; responseSchema: NormalizedSchema; initialResponseContainer?: any;}): Promise<AsyncIterable<{[key: string]: any; $unknown?... npmjs.com
• Signature changed event-streams:EventStreamSerde.serializeEventStream
  Was serializeEventStream({eventStream, requestSchema, initialRequest}: {eventStream: AsyncIterable<any>; requestSchema: NormalizedSchema; initialRequest?: any;}): Promise<IHttpRequest["body"] | Uint8Array>; now... npmjs.com
• Signature changed retry:Retry.modifiedCostType
  Was static modifiedCostType(): "TRANSIENT" | "THROTTLING"; now static modifiedCostType(): "THROTTLING" | "TRANSIENT". npmjs.com
• Signature changed retry:Retry.throttlingDelay
  Was static throttlingDelay(): 1000 | 500; now static throttlingDelay(): 500 | 1000. npmjs.com
• Signature changed schema:TypeRegistry.find
  Was find(predicate: (schema: ISchema) => boolean): number | "unit" | import("@smithy/types").StaticSimpleSchema | import("@smithy/types").StaticListSchema | import("@smithy/types").StaticMapSchema |... npmjs.com
• Signature changed serde:expectInt
  Was const expectInt: (value: any) => number | undefined; now const expectInt: typeof expectLong. npmjs.com
• Signature changed serde:handleFloat
  Was const handleFloat: (value: string | number) => number | undefined; now const handleFloat: typeof limitedParseDouble. npmjs.com
• Signature changed serde:limitedParseFloat
  Was const limitedParseFloat: (value: string | number) => number | undefined; now const limitedParseFloat: typeof limitedParseDouble. npmjs.com
• Signature changed serde:strictParseFloat
  Was const strictParseFloat: (value: string | number) => number | undefined; now const strictParseFloat: typeof strictParseDouble. npmjs.com

And 1 more in this version.

3.33.0

3 breaking changes, first published August 14, 2026.

• Removed protocols:HttpHandlerExtensionConfigType.httpHandler
  HttpHandlerExtensionConfigType.httpHandler was removed in @smithy/core 3.33.0 npmjs.com
• Signature changed protocols:getHttpHandlerExtensionConfiguration
  Was const getHttpHandlerExtensionConfiguration: <HandlerConfig extends object = {}>(runtimeConfig: HttpHandlerExtensionConfigType<HandlerConfig>) => {setHttpHandler(handler: HttpHandler<HandlerConfig>): void; httpHandler()... npmjs.com
• Signature changed protocols:HttpHandlerExtensionConfigType
  Was type HttpHandlerExtensionConfigType<HandlerConfig extends object = {}> = Partial<{httpHandler: HttpHandler<HandlerConfig>;}>; now type HttpHandlerExtensionConfigType<HandlerConfig extends object = {}> = Partial<{requestHandler... npmjs.com

3.31.1

5 breaking changes, first published July 29, 2026.

• Removed schema:NormalizedSchema.structIteratorCbor
  NormalizedSchema.structIteratorCbor was removed in @smithy/core 3.31.1 npmjs.com
• Signature changed cbor:CborCodec.createDeserializer
  Was createDeserializer(): CborShapeDeserializer; now createDeserializer(): CborShapeDeserializer2. npmjs.com
• Signature changed cbor:CborCodec.createSerializer
  Was createSerializer(): CborShapeSerializer; now createSerializer(): CborShapeSerializer2. npmjs.com
• Signature changed cbor:SmithyRpcV2CborProtocol.deserializer
  Was protected deserializer: import(".").CborShapeDeserializer; now protected deserializer: import(".").CborShapeDeserializer2. npmjs.com
• Signature changed cbor:SmithyRpcV2CborProtocol.serializer
  Was protected serializer: import(".").CborShapeSerializer; now protected serializer: import(".").CborShapeSerializer2. npmjs.com

Check your code

These are the changes. To see which of them reach your code, scan a public repository, or have your coding agent call check_code with your manifest or lockfile over MCP. The API reads every change in every version, not only the newest. On Team and up, a fix pull request opens for the changes that reach a connected repository. Nothing merges or deploys.