Hyperledger Sawtooth provides a REST API (see the REST API Reference) that allows clients to interact with a validator using common HTTP/JSON standards. It is a pragmatic RESTful API that provides a language-neutral interface for submitting transactions and reading blocks.
The Sawtooth REST API is intended only as a simple interface for client use. The validator and transaction processors use a ZMQ/Protobuf interface that is more efficient and robust, as well as slightly more complicated. Note that clients also have the option of using the ZMQ/Protobuf interface to communicate with the validator.
The REST API is a lightweight layer on top of Sawtooth's internal ZMQ communication. As a result, the API offers no authorization. It simply passes every request to the validator to be authorized with signature verification or another strategy that is defined by a transaction processor.
The REST API process runs as a separate process, rather than as part of the validator process. It treats the validator as a black box, simply submitting transactions and fetching the results.
The REST API uses a JSON envelope to send metadata back to clients in a way that is simple to parse and easily customized. All successful requests return data in an envelope that may include the requested resource, chain head ID, a link to the requested resource, and paging information (described below).
The JSON response envelope also includes the details needed to parse errors. For more information, see the Error Responses.
The API endpoints include RESTful references to resources stored in the Sawtooth ledger that clients might be interested in, like blocks and transactions, as well as RESTful metadata like batch status.
All endpoints that return lists of resources will automatically paginate the results, up to a default limit of 100 resources.