{"openapi":"3.1.0","info":{"title":"Stamp Duty Calculator API","version":"1.0.0","summary":"Free public API for Indian property stamp duty + registration fee calculation. No API key, no signup.","description":"Deterministic calculation against a bundled dataset of state IGR (Inspector General of Registration) rates. Snapshot: 2025-04-01. Covers 24 states across sale, gift, lease, mortgage, exchange, partition deeds. Treat as a goodwill resource — cache aggressively.","contact":{"name":"Krake Labs India","url":"https://krakelabsindia.com"},"license":{"name":"Best-effort free service","url":"https://stampduty.krakelabsindia.com/developers"}},"servers":[{"url":"https://stampduty.krakelabsindia.com","description":"Production"}],"tags":[{"name":"Calculate","description":"Stamp duty + registration calculation"},{"name":"Meta","description":"Dataset metadata and state list"}],"paths":{"/api/calculate":{"get":{"tags":["Calculate"],"summary":"Calculate stamp duty + registration fee","parameters":[{"name":"state","in":"query","required":true,"schema":{"type":"string","example":"MH"},"description":"ISO 3166-2:IN code or slug (e.g. MH or maharashtra)"},{"name":"deedType","in":"query","required":true,"schema":{"type":"string","enum":["sale","gift","gift-blood-relative","lease","mortgage","exchange","partition"],"example":"sale"},"description":"Deed type — sale, gift, lease, mortgage, etc."},{"name":"consideration","in":"query","required":true,"schema":{"type":"number","minimum":1,"example":8500000},"description":"Property value in INR."},{"name":"isWomanBuyer","in":"query","required":false,"schema":{"type":"boolean","example":true}},{"name":"cityTier","in":"query","required":false,"schema":{"type":"string","enum":["metro","other"],"example":"metro"}}],"responses":{"200":{"description":"Successful calculation","content":{"application/json":{"schema":{"$ref":"#/components/schemas/CalcResult"}}}},"400":{"description":"Invalid input"},"404":{"description":"Unknown state or deedType"},"429":{"description":"Rate limit exceeded"}}},"post":{"tags":["Calculate"],"summary":"Calculate via JSON body","requestBody":{"required":true,"content":{"application/json":{"schema":{"$ref":"#/components/schemas/CalcInput"},"example":{"state":"MH","deedType":"sale","consideration":8500000,"isWomanBuyer":true,"cityTier":"metro"}}}},"responses":{"200":{"description":"Successful calculation","content":{"application/json":{"schema":{"$ref":"#/components/schemas/CalcResult"}}}}}}},"/api/states":{"get":{"tags":["Meta"],"summary":"List all supported states with deed types","responses":{"200":{"description":"State list","content":{"application/json":{"schema":{"type":"object"}}}}}}},"/api/meta":{"get":{"tags":["Meta"],"summary":"Dataset metadata","responses":{"200":{"description":"Counts and snapshot date","content":{"application/json":{"schema":{"type":"object"}}}}}}}},"components":{"schemas":{"CalcInput":{"type":"object","required":["state","deedType","consideration"],"properties":{"state":{"type":"string","example":"MH"},"deedType":{"type":"string","enum":["sale","gift","gift-blood-relative","lease","mortgage","exchange","partition"],"example":"sale"},"consideration":{"type":"number","example":8500000},"isWomanBuyer":{"type":"boolean","example":true},"cityTier":{"type":"string","enum":["metro","other"],"example":"metro"}}},"CalcResult":{"type":"object","properties":{"state":{"type":"object","properties":{"code":{"type":"string","example":"MH"},"name":{"type":"string","example":"Maharashtra"}}},"deedType":{"type":"string","example":"sale"},"deedLabel":{"type":"string","example":"Sale deed"},"consideration":{"type":"number","example":8500000},"cityTier":{"type":"string","example":"metro"},"isWomanBuyer":{"type":"boolean","example":true},"stampDuty":{"type":"number","example":425000},"registrationFee":{"type":"number","example":30000},"total":{"type":"number","example":455000},"breakdown":{"type":"array","items":{"type":"object","properties":{"label":{"type":"string"},"amount":{"type":"number"},"formula":{"type":"string"}}}},"sourceUrl":{"type":"string"},"asOf":{"type":"string","example":"2025-04-01"},"honestyNotes":{"type":"array","items":{"type":"string"}}}}}}}