{
  "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"
              }
            }
          }
        }
      }
    }
  }
}