Protocol Buffers JSON Mapping

{
  "$id": "protobuf-json-mapping.json",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "Protocol Buffers JSON Mapping",
  "description": "Schema describing the proto3 JSON encoding rules for Protocol Buffers messages. Proto3 JSON mapping defines how protobuf scalar types, well-known types, and composite types are represented in JSON format as specified by the Protocol Buffers Language Guide.",
  "type": "object",
  "properties": {
    "message": {
      "type": "object",
      "description": "A protobuf message serialized to JSON. Each field uses its proto field name in lowerCamelCase as the JSON key. Fields with default values are omitted by default.",
      "additionalProperties": true
    },
    "@type": {
      "type": "string",
      "description": "The type URL for google.protobuf.Any messages, identifying the packed message type (e.g., type.googleapis.com/package.MessageName).",
      "format": "uri",
      "examples": [
        "type.googleapis.com/google.protobuf.Duration",
        "type.googleapis.com/google.protobuf.Struct"
      ]
    },
    "value": {
      "description": "The value field used by wrapper types (e.g., google.protobuf.StringValue, google.protobuf.Int32Value) and google.protobuf.Value."
    }
  },
  "definitions": {
    "Duration": {
      "type": "string",
      "description": "google.protobuf.Duration encoded as a string with suffix 's' for seconds (e.g., '3.5s'). Nanosecond precision is supported.",
      "pattern": "^-?[0-9]+(\\.[0-9]+)?s$",
      "examples": ["1.5s", "0.001s", "-42s"]
    },
    "Timestamp": {
      "type": "string",
      "description": "google.protobuf.Timestamp encoded as an RFC 3339 date-time string in UTC with suffix 'Z'.",
      "format": "date-time",
      "examples": ["2025-01-15T12:00:00Z", "2025-06-01T00:00:00.000Z"]
    },
    "FieldMask": {
      "type": "string",
      "description": "google.protobuf.FieldMask encoded as a single comma-delimited string of field paths in lowerCamelCase.",
      "examples": ["fieldOne,fieldTwo.subField", "name,displayName"]
    },
    "Struct": {
      "type": "object",
      "description": "google.protobuf.Struct encoded as a regular JSON object with string keys and google.protobuf.Value values.",
      "additionalProperties": {
        "$ref": "#/definitions/Value"
      }
    },
    "Value": {
      "description": "google.protobuf.Value can represent any JSON value: null, number, string, boolean, struct, or list.",
      "oneOf": [
        { "type": "null" },
        { "type": "number" },
        { "type": "string" },
        { "type": "boolean" },
        { "type": "object", "additionalProperties": true },
        { "type": "array" }
      ]
    },
    "ListValue": {
      "type": "array",
      "description": "google.protobuf.ListValue encoded as a JSON array of google.protobuf.Value elements.",
      "items": {
        "$ref": "#/definitions/Value"
      }
    },
    "NullValue": {
      "type": "null",
      "description": "google.protobuf.NullValue is always encoded as JSON null."
    },
    "Empty": {
      "type": "object",
      "description": "google.protobuf.Empty encoded as an empty JSON object.",
      "additionalProperties": false
    },
    "Int64Value": {
      "type": "string",
      "description": "64-bit integer types (int64, uint64, sint64, fixed64, sfixed64) are encoded as decimal strings in JSON to preserve precision.",
      "pattern": "^-?[0-9]+$"
    },
    "BytesValue": {
      "type": "string",
      "description": "The bytes scalar type is encoded as a base64-encoded string using standard base64 encoding with padding.",
      "contentEncoding": "base64"
    },
    "EnumValue": {
      "description": "Enum values are encoded as the string name of the enum value. If unrecognized, the integer value is used instead.",
      "oneOf": [
        { "type": "string" },
        { "type": "integer" }
      ]
    },
    "RepeatedField": {
      "type": "array",
      "description": "Repeated fields are encoded as JSON arrays. An empty repeated field may be omitted or represented as an empty array."
    },
    "MapField": {
      "type": "object",
      "description": "Map fields are encoded as JSON objects. Map keys are always converted to strings. Sort order is not guaranteed.",
      "additionalProperties": true
    }
  },
  "additionalProperties": true
}