Schema

A schema defines a type system of GraphQL API. It describes the complete set of possible data (objects, fields, relationships, everything) that a client can access.

• Root types

• Non-root types

• Query types

• Subscription types (coming soon)

• Mutation types

• Syntax

Root types

GraphQL schema has three root types:

• query

• mutation

• subscription (coming soon)

The query type defines GraphQL operations that retrieve data from the server.

The mutation type defines GraphQL operations that change data on the server. It is analogous to performing HTTP verbs such as POST, PATCH, and DELETE. Mutations are used to send messages to the blockchain. We recommend to do it only via SDK, not directly.

The subscription root type – a long‐lived request that fetches data in response to source events.

Check out TVM-SDK net module - the wrapper over GraphQL API for root queries and subscriptions.

Non-root types

See non-root type descriptions in Field descriptions section.

Query types

Root resolvers

name	description
info	Info query is used to get GraphQL API version, as well as health parameters of the API, such as latency of blocks, messages and transactions
blockchain	API that includes a set of functions for pagination of blocks, key blocks, transactions and account’s transactions and messages.
blocks	Blocks collection
accounts	Accounts collection
messages	Messages collection
transaction	Transactions collection

Subscription types (Soon)

• blocks

• accounts

• messages

• transaction

Mutation types

• postRequests - used to send messages to blockchain.

Syntax

Read about GraphQL syntax in its official documentation. In this example we query account info:

query {
  blockchain{
   account(address:"0:653b9a6452c7a982c6dc92b2da9eba832ade1c467699ebb3b43dca6d77b780dd"){
    info{
      address
      acc_type
      balance
      last_paid
      last_trans_lt
      boc
      data
      code
      library
      data_hash
      code_hash
      library_hash
    }
    transactions(last:1){
      edges{
        node{
          hash
          now
          balance_delta
        }
      }
    }
  }
  }
}

Here you can see a request for account's information and the last transaction with a subset of fields. All available fields with their descriptions can be found in data schema in playground.

A selection set must contain only scalar fields, otherwise you will get an error. A scalar field describes one discrete piece of information available to a request within a selection set. If field is an object, you need to specify the fields of this object.

Read more in the next sections.