{"openapi":"3.1.0","info":{"title":"Balloon Decor API","version":"1.0.0","description":"Party-balloon maths as an API, computed locally and deterministically — the helium-lift and balloon-count numbers a party planner or balloon artist decorates by. The helium endpoint gives a balloon’s lift from its inflated diameter: net lift is the inflated volume times the difference between air and helium density, about 1.046 grams per litre, so a fully inflated 11-inch latex balloon (around 11.4 litres) lifts roughly 12 grams gross and about 9 after its own weight, while a 36-inch giant lifts hundreds of grams. The float endpoint flips it around — how many balloons to float a payload = the weight divided by the net lift per balloon, rounded up, so a 50-gram card floats on six 11-inch balloons. The garland endpoint sizes an organic balloon garland or arch from its length: about 12 balloons per foot in a mix of sizes — roughly 40 % 5-inch, 45 % 11-inch and 15 % 16-inch for that full, textured look — so a 10-foot garland takes about 120 balloons, denser if you want it lush. Everything is computed locally and deterministically, so it is instant and private. Ideal for party-planning, event-decor, balloon-artist and celebration app developers, decor-estimator and shopping-list tools, and event software. Pure local computation — no key, no third-party service, instant. Inches and grams. Live, nothing stored. 3 compute endpoints.","contact":{"name":"PremiumApi","url":"https://www.oanor.com/by/premiumapi"}},"servers":[{"url":"https://api.oanor.com/balloon-api","description":"oanor gateway"}],"tags":[{"name":"Balloon"},{"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/float":{"get":{"operationId":"get_v1_float","tags":["Balloon"],"summary":"Balloons to float a payload","description":"","parameters":[{"name":"payload_g","in":"query","required":true,"description":"Weight to lift (g)","schema":{"type":"string"},"example":"50"},{"name":"diameter_in","in":"query","required":false,"description":"Balloon diameter (default 11)","schema":{"type":"string"},"example":"11"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"note":"Balloons needed = payload ÷ net lift per balloon, rounded up. Helium leaks, so floats fade within a day or two — add a few extra and use a balloon treatment (HiFloat) for longevity.","inputs":{"payload_g":50,"diameter_in":11},"balloons_needed":6,"net_lift_per_balloon_g":9.15},"meta":{"timestamp":"2026-06-06T15:30:49.742Z","request_id":"5acab8ef-a158-4abd-9980-8c8224cc2ad7"},"status":"ok","message":"Balloons to float","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/garland":{"get":{"operationId":"get_v1_garland","tags":["Balloon"],"summary":"Garland balloon count","description":"","parameters":[{"name":"length_ft","in":"query","required":true,"description":"Garland/arch length (ft)","schema":{"type":"string"},"example":"10"},{"name":"balloons_per_foot","in":"query","required":false,"description":"Density (default 12)","schema":{"type":"string"},"example":"12"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"note":"An organic balloon garland uses roughly 12 balloons per foot in a mix of sizes — about 40 % 5\", 45 % 11\" and 15 % 16\" for depth and texture. Denser (16/ft) looks lush; sparser (8/ft) is lighter. Buy ~10 % extra for pops.","inputs":{"length_ft":10,"balloons_per_foot":12},"size_mix":{"5in":48,"11in":54,"16in":18},"total_balloons":120},"meta":{"timestamp":"2026-06-06T15:30:49.845Z","request_id":"cbdad343-c305-4adf-abc0-9dd0e25152db"},"status":"ok","message":"Garland count","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/helium":{"get":{"operationId":"get_v1_helium","tags":["Balloon"],"summary":"Helium lift of a balloon","description":"","parameters":[{"name":"diameter_in","in":"query","required":true,"description":"Inflated diameter (in)","schema":{"type":"string"},"example":"11"},{"name":"balloon_weight_g","in":"query","required":false,"description":"Latex weight (g) override","schema":{"type":"string"}}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"note":"Helium lift = inflated volume × (air − helium density) = ~1.046 g per litre. A fully inflated 11\" latex balloon (~11.4 L) lifts about 12 g gross, ~9 g after the balloon's own weight. Net lift floats the string and any attached weight.","inputs":{"diameter_in":11,"balloon_weight_g":2.8},"net_lift_g":9.15,"gross_lift_g":11.95,"volume_liters":11.42},"meta":{"timestamp":"2026-06-06T15:30:49.943Z","request_id":"87e3d522-4906-4087-bb41-d58b2e515974"},"status":"ok","message":"Helium lift","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/meta":{"get":{"operationId":"get_v1_meta","tags":["Meta"],"summary":"Spec","description":"","parameters":[],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"notes":"Diameters in inches, lift in grams. Net helium lift ≈ 1.046 g/L (air 1.225 − helium 0.1786); subtract the latex weight. Garland ≈ 12 balloons/ft. Party planning — helium and temperature vary. For physics buoyancy use a buoyancy API.","service":"balloon-api","endpoints":{"GET /v1/meta":"This document.","GET /v1/float":"Balloons needed to float a payload weight.","GET /v1/helium":"Helium lift (gross & net) of a balloon from its inflated diameter.","GET /v1/garland":"Balloon count and size mix for an organic garland of a given length."},"description":"Party-balloon maths: helium lift by size, balloons to float a payload, and the balloon count for an arch/garland."},"meta":{"timestamp":"2026-06-06T15:30:50.035Z","request_id":"9d95bb03-eeda-40a9-8745-922b671e1d06"},"status":"ok","message":"Meta","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"}}}}},"x-oanor-pricing":[{"slug":"free","name":"Free","price_cents_month":0,"monthly_call_quota":7320,"rps_limit":2,"hard_limit":true},{"slug":"starter","name":"Starter","price_cents_month":388,"monthly_call_quota":59100,"rps_limit":6,"hard_limit":true},{"slug":"pro","name":"Pro","price_cents_month":1090,"monthly_call_quota":240500,"rps_limit":15,"hard_limit":true},{"slug":"mega","name":"Mega","price_cents_month":3470,"monthly_call_quota":1372000,"rps_limit":40,"hard_limit":true}],"x-oanor-marketplace-url":"https://www.oanor.com/api/balloon-api"}