{"openapi":"3.1.0","info":{"title":"Guitar Luthier API","version":"1.0.0","description":"Guitar and luthier maths as an API, computed locally and deterministically — the string-tension and fret numbers a player, builder or tech sets an instrument up with. The string-tension endpoint gives the tension a string pulls at pitch from the physics, tension = unit weight × (2 × scale length × frequency)² ÷ 386.4, where the unit weight (lb/in) comes from the string maker's chart — a .010 plain-steel high E on a 25.5-inch scale tuned to 329.6 Hz pulls about 16 lb. The fret-position endpoint gives the distance from the nut to any fret in equal temperament, scale × (1 − 2^(−fret/12)), so the 12th fret sits exactly halfway and the first fret of a 25.5-inch scale is 1.43 inches down — the maths behind every fretboard slot. The set-tension endpoint sums a whole string set into the total load on the neck (a typical six-string runs ~95–120 lb), the number that decides whether a gauge or tuning change needs a truss-rod re-setup. Everything is computed locally and deterministically, so it is instant and private. Ideal for luthier and guitar-tech apps, string-tension and fret-slotting calculators, setup and re-string tools, and music-gear sites. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 compute endpoints. Get unit weights from the string maker's chart. For note↔frequency conversion use a music-theory API.","contact":{"name":"PremiumApi","url":"https://www.oanor.com/by/premiumapi"}},"servers":[{"url":"https://api.oanor.com/guitar-api","description":"oanor gateway"}],"tags":[{"name":"Guitar"},{"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/fret-position":{"get":{"operationId":"get_v1_fret_position","tags":["Guitar"],"summary":"Fret distance from the nut","description":"","parameters":[{"name":"scale_length_in","in":"query","required":true,"description":"Scale length in inches","schema":{"type":"string"},"example":"25.5"},{"name":"fret_number","in":"query","required":true,"description":"Fret number","schema":{"type":"string"},"example":"12"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK"},"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/set-tension":{"get":{"operationId":"get_v1_set_tension","tags":["Guitar"],"summary":"Total neck tension of a set","description":"","parameters":[{"name":"unit_weights_lb_in","in":"query","required":true,"description":"Comma-separated unit weights (lb/in)","schema":{"type":"string"},"example":"0.0003297,0.0001705,0.0000889,0.00006402,0.00003744,0.00002215"},{"name":"frequencies_hz","in":"query","required":true,"description":"Comma-separated frequencies (Hz)","schema":{"type":"string"},"example":"82.41,110,146.83,196,246.94,329.63"},{"name":"scale_length_in","in":"query","required":true,"description":"Scale length in inches","schema":{"type":"string"},"example":"25.5"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK"},"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/string-tension":{"get":{"operationId":"get_v1_string_tension","tags":["Guitar"],"summary":"Tension of one string","description":"","parameters":[{"name":"unit_weight_lb_in","in":"query","required":true,"description":"Unit weight in lb/in (maker chart)","schema":{"type":"string"},"example":"0.00002215"},{"name":"scale_length_in","in":"query","required":true,"description":"Scale length in inches","schema":{"type":"string"},"example":"25.5"},{"name":"frequency_hz","in":"query","required":true,"description":"Tuned frequency in Hz","schema":{"type":"string"},"example":"329.63"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK"},"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"},"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":700,"rps_limit":2,"hard_limit":true},{"slug":"starter","name":"Starter","price_cents_month":455,"monthly_call_quota":16500,"rps_limit":8,"hard_limit":true},{"slug":"pro","name":"Pro","price_cents_month":1580,"monthly_call_quota":98000,"rps_limit":20,"hard_limit":true},{"slug":"mega","name":"Mega","price_cents_month":4780,"monthly_call_quota":330000,"rps_limit":48,"hard_limit":true}],"x-oanor-marketplace-url":"https://www.oanor.com/api/guitar-api"}