{"openapi":"3.1.0","info":{"title":"Colligative Properties API","version":"1.0.0","description":"Colligative-properties maths for solutions as an API, computed locally and deterministically. The osmotic endpoint computes the osmotic pressure by the van 't Hoff equation, π = i·M·R·T, from the molarity, the temperature and the van 't Hoff factor (the number of dissolved particles per formula unit — 1 for sugar, 2 for NaCl, 3 for CaCl₂), reported in atmospheres, bar and kilopascals, and also solves the molarity back from a measured pressure. The freezing endpoint computes the freezing-point depression, ΔTf = i·Kf·m, from the molality and the cryoscopic constant (1.86 °C·kg/mol for water), and the new freezing point. The boiling endpoint computes the boiling-point elevation, ΔTb = i·Kb·m, from the ebullioscopic constant (0.512 °C·kg/mol for water), and the new boiling point. Everything is computed locally and deterministically, so it is instant and private. Ideal for chemistry, biology and food-science tools, reverse-osmosis and desalination estimates, antifreeze and de-icing formulation, lab and education apps. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is colligative-properties chemistry; for solution dilution use a dilution API and for pH and buffers use a pH API.","contact":{"name":"PremiumApi","url":"https://www.oanor.com/by/premiumapi"}},"servers":[{"url":"https://api.oanor.com/osmosis-api","description":"oanor gateway"}],"tags":[{"name":"Colligative"},{"name":"Meta"}],"components":{"securitySchemes":{"oanorKey":{"type":"apiKey","in":"header","name":"x-oanor-key","description":"Get your key at https://www.oanor.com/developer/keys"}}},"security":[{"oanorKey":[]}],"paths":{"/v1/boiling":{"get":{"operationId":"get_v1_boiling","tags":["Colligative"],"summary":"Boiling-point elevation","description":"","parameters":[{"name":"molality","in":"query","required":true,"description":"Molality m (mol/kg)","schema":{"type":"string"},"example":"1"},{"name":"kb","in":"query","required":false,"description":"Ebullioscopic constant Kb (default 0.512)","schema":{"type":"string"},"example":"0.512"},{"name":"van_t_hoff_factor","in":"query","required":false,"description":"van 't Hoff factor i (default 1)","schema":{"type":"string"},"example":"1"},{"name":"solvent_boiling_point","in":"query","required":false,"description":"Solvent boiling point (°C, default 100)","schema":{"type":"string"},"example":"100"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"note":"ΔTb = i·Kb·m. Kb for water = 0.512 °C·kg/mol. The solution boils above the pure-solvent point.","inputs":{"kb":0.512,"molality":1,"van_t_hoff_factor":1,"solvent_boiling_point":100},"new_boiling_point_c":100.512,"boiling_point_elevation_c":0.512},"meta":{"timestamp":"2026-06-04T18:38:22.896Z","request_id":"8dc38475-a8b5-4552-bef3-53c543cbdbb4"},"status":"ok","message":"Boiling point elevation","success":true}}}},"401":{"description":"Missing or invalid x-oanor-key header"},"402":{"description":"Active subscription required"},"429":{"description":"Rate-limit or monthly quota reached"},"502":{"description":"Upstream did not respond"}}}},"/v1/freezing":{"get":{"operationId":"get_v1_freezing","tags":["Colligative"],"summary":"Freezing-point depression","description":"","parameters":[{"name":"molality","in":"query","required":true,"description":"Molality m (mol/kg)","schema":{"type":"string"},"example":"1"},{"name":"kf","in":"query","required":false,"description":"Cryoscopic constant Kf (default 1.86)","schema":{"type":"string"},"example":"1.86"},{"name":"van_t_hoff_factor","in":"query","required":false,"description":"van 't Hoff factor i (default 1)","schema":{"type":"string"},"example":"1"},{"name":"solvent_freezing_point","in":"query","required":false,"description":"Solvent freezing point (°C, default 0)","schema":{"type":"string"},"example":"0"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"note":"ΔTf = i·Kf·m. Kf for water = 1.86 °C·kg/mol. 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