core-lightning/doc/schemas/signmessage.schema.json

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "additionalProperties": false,
  "required": [
    "signature",
    "recid",
    "zbase"
  ],
  "properties": {
    "signature": {
      "type": "hex",
      "description": "The signature",
      "minLength": 128,
      "maxLength": 128
    },
    "recid": {
      "type": "hex",
      "description": "The recovery id (0, 1, 2 or 3)",
      "minLength": 2,
      "maxLength": 2
    },
    "zbase": {
      "type": "string",
      "description": "*signature* and *recid* encoded in a style compatible with **lnd**'s [SignMessageRequest](https://api.lightning.community/#grpc-request-signmessagerequest)"
    }
  }
}