{
  "openapi": "3.1.0",
  "info": {
    "title": "UK Lease Extension Term Calculator API",
    "description": "Computes the arithmetic of a lease extension, such as years remaining and a proposed new term. Pre-launch design; endpoints are not live yet.",
    "version": "0.1.0",
    "x-planned-pricing": {
      "model": "free tier for evaluation, paid tiers by volume",
      "status": "planned; nothing charged before launch"
    }
  },
  "servers": [
    {
      "url": "https://openapiregistry.com/api/v1/lease-renewal-calc",
      "description": "Pre-launch: endpoints are not live yet and answer 503."
    }
  ],
  "security": [
    {
      "ApiKeyAuth": []
    }
  ],
  "paths": {
    "/lease/renewal": {
      "get": {
        "summary": "Compute lease renewal maths",
        "description": "Computes years remaining on a lease and the resulting term of a fixed extension.",
        "tags": [
          "property"
        ],
        "operationId": "lease-renewal-calc-get-lease-renewal",
        "parameters": [
          {
            "name": "start",
            "in": "query",
            "required": true,
            "description": "Lease start date (YYYY-MM-DD).",
            "schema": {
              "type": "string"
            }
          },
          {
            "name": "termYears",
            "in": "query",
            "required": true,
            "description": "Original term in years.",
            "schema": {
              "type": "integer"
            }
          },
          {
            "name": "extendTo",
            "in": "query",
            "required": false,
            "description": "Proposed new term in years.",
            "schema": {
              "type": "integer"
            }
          }
        ],
        "responses": {
          "200": {
            "description": "Renewal maths computed.",
            "content": {
              "application/json": {
                "example": {
                  "yearsRemaining": 68,
                  "extendTo": 199,
                  "notation": "as at today"
                },
                "schema": {
                  "type": "object"
                }
              }
            }
          },
          "400": {
            "description": "Lease appears to have expired."
          }
        }
      }
    }
  },
  "components": {
    "securitySchemes": {
      "ApiKeyAuth": {
        "type": "apiKey",
        "in": "header",
        "name": "X-API-Key",
        "description": "Planned for launch: an API key issued on request. Free tier for evaluation, paid tiers by volume; nothing is charged before launch."
      }
    }
  }
}