openapi: 3.1.0
info:
  title: "NEAR Protocol RPC: Get next light client block"
  description: Advance a light client's verified chain by fetching the next block header after a known Base58 head hash.
  version: 1.0.0
servers:
  - url: https://rpc.mainnet.fastnear.com
    description: Mainnet
  - url: https://rpc.testnet.fastnear.com
    description: Testnet
  - url: https://archival-rpc.mainnet.fastnear.com
    description: Mainnet Archival
  - url: https://archival-rpc.testnet.fastnear.com
    description: Testnet Archival
paths:
  /:
    post:
      operationId: next_light_client_block
      summary: Get next light client block
      description: Advance a light client's verified chain by fetching the next block header after a known Base58 head hash.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - jsonrpc
                - id
                - method
                - params
              properties:
                jsonrpc:
                  type: string
                  enum:
                    - "2.0"
                id:
                  type: string
                  example: fastnear
                method:
                  type: string
                  enum:
                    - next_light_client_block
                params:
                  type: object
                  properties:
                    last_block_hash:
                      type: string
                      description: Base58-encoded hash
                  required:
                    - last_block_hash
            examples:
              mainnet:
                summary: Get next light client block (Mainnet)
                value:
                  jsonrpc: "2.0"
                  id: fastnear
                  method: next_light_client_block
                  params:
                    last_block_hash: 9XN7MtDywZvfGx6TKy1MT2iCZkKuHikJXmNazxdZ4x6T
              testnet:
                summary: Get next light client block (Testnet)
                value:
                  jsonrpc: "2.0"
                  id: fastnear
                  method: next_light_client_block
                  params:
                    last_block_hash: 6JYj6i1FaUCzdoqy41CqUcZJxa5n9EmLEENRDH2gLm5u
      responses:
        "200":
          description: Successful response
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/JsonRpcResponse"
        "403":
          description: The supplied API key was not recognized.
          content:
            text/plain:
              schema:
                type: string
              example: Invalid API key
security:
  - {}
  - BearerAuth: []
  - ApiKeyAuth: []
components:
  securitySchemes:
    BearerAuth:
      type: http
      scheme: bearer
      description: "FastNEAR API key as an `Authorization: Bearer` header. Preferred for backends, workers, and proxies because it keeps the key out of URLs and logs."
    ApiKeyAuth:
      type: apiKey
      in: query
      name: apiKey
      description: FastNEAR API key as the `apiKey` query parameter. Handy for curl or clients that cannot set headers, but the key can end up in URLs, logs, and shell history.
  schemas:
    JsonRpcResponse:
      type: object
      required:
        - jsonrpc
        - id
      properties:
        jsonrpc:
          type: string
          enum:
            - "2.0"
        id:
          oneOf:
            - type: string
            - type: number
        result:
          type: object
          description: A state for the current head of a light client. More info [here](https://nomicon.io/ChainSpec/LightClient).
          properties:
            approvals_after_next:
              type: array
              items:
                type:
                  - string
                  - "null"
                description: Base58-encoded cryptographic signature
            inner_lite:
              type: object
              description: A part of a state for the current head of a light client. More info [here](https://nomicon.io/ChainSpec/LightClient).
              properties:
                block_merkle_root:
                  type: string
                  description: Base58-encoded hash
                epoch_id:
                  type: string
                  description: Base58-encoded hash
                height:
                  type: integer
                  format: uint64
                  minimum: 0
                next_bp_hash:
                  type: string
                  description: Base58-encoded hash
                next_epoch_id:
                  type: string
                  description: Base58-encoded hash
                outcome_root:
                  type: string
                  description: Base58-encoded hash
                prev_state_root:
                  type: string
                  description: Base58-encoded hash
                timestamp:
                  type: integer
                  description: Legacy json number. Should not be used.
                  format: uint64
                  minimum: 0
                timestamp_nanosec:
                  type: string
              required:
                - height
                - epoch_id
                - next_epoch_id
                - prev_state_root
                - outcome_root
                - timestamp
                - timestamp_nanosec
                - next_bp_hash
                - block_merkle_root
            inner_rest_hash:
              type: string
              description: Base58-encoded hash
            next_block_inner_hash:
              type: string
              description: Base58-encoded hash
            next_bps:
              type: array
              items:
                type: object
                description: One of multiple possible types
            prev_block_hash:
              type: string
              description: Base58-encoded hash
        error:
          type: object
          properties:
            code:
              type: integer
            message:
              type: string
            data:
              type: object