API Reference > itwin-client > iTwinServiceClients iTwinServiceClients Classes for communicating with various iTwin services. Classes Name Description AuthenticationError Error for issues with authentication. Beta ChunkedQueryContext Context for holding chunked query data. Beta Client Base class for all Client implementations Beta ECInstance Base class for all typed instances mapped to ECInstance-s in an ECDb Beta RequestGlobalOptions Beta ResponseError Error object that's thrown/rejected if the Request fails due to a network error, or if the status is not in the range of 200-299 (inclusive) Beta SasUrlExpired Error thrown when sas-url provided for download has expired Beta WsgClient Base class for Client implementations of services that are based on WSG Beta WsgError Error that was returned by a WSG based service. Beta WsgInstance Base class for all typed instances mapped to ECInstance-s in both an ECDb, and the WSG repository Beta WsgQuery Base class for Query objects. Beta Constants Name Description requestIdHeaderName Beta Interfaces Name Description CancelRequest Interface to cancel a request Beta FileHandler Handler for file system, and upload / download. Beta HttpRequestOptions Additional options used for requests Beta ProgressInfo Beta RequestBasicCredentials Beta RequestOptions Beta RequestQueryOptions Typical option to query REST API. Beta RequestQueryStringifyOptions Beta RequestTimeoutOptions Option to control the time outs Beta Response Response object if the request was successful. Beta WsgRequestOptions Options for WSG requests sent to the service Beta Type Aliases Name Description ChangeState Beta ProgressCallback Last Updated: 29 November, 2022