{"openapi":"3.1.0","info":{"title":"Vinyl Record API","version":"1.0.0","description":"Vinyl-record geometry maths as an API, computed locally and deterministically — the playing-time, groove-length and groove-speed numbers a cutting engineer, pressing plant or audio hobbyist works a record out with. The playing-time endpoint gives a side's maximum time = the number of groove turns ÷ the turntable speed, where the turns = the recorded band's radial width ÷ the groove pitch (the spacing between adjacent grooves): a 12-inch LP with ~85 mm of band at a 100 µm pitch holds about 850 turns, so at 33⅓ rpm that is roughly 25 minutes a side — a tighter pitch fits more time but cuts groove amplitude and so loudness and bass, the classic time-versus-level trade. The groove-length endpoint unrolls the spiral: length ≈ turns × the mean circumference (π × the average of the outer and inner diameters), on the order of 400–500 metres for an LP side, the whole of which the stylus traces once. The groove-speed endpoint gives the linear speed under the stylus = 2π × rpm/60 × radius, so the outer grooves of an LP pass at about 50 cm/s but the inner ones only ~20 cm/s — the cause of inner-groove distortion and why engineers place quieter tracks last. Everything is computed locally and deterministically, so it is instant and private. Ideal for record-cutting and mastering tools, hi-fi and collector apps, and audio-engineering calculators. Pure local computation — no key, no third-party service, instant. 3 compute endpoints. For musical note and tempo maths use a music API.","contact":{"name":"PremiumApi","url":"https://www.oanor.com/by/premiumapi"}},"servers":[{"url":"https://api.oanor.com/vinyl-api","description":"oanor gateway"}],"tags":[{"name":"Vinyl"},{"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/groove-length":{"get":{"operationId":"get_v1_groove_length","tags":["Vinyl"],"summary":"Total spiral groove length","description":"","parameters":[{"name":"outer_diameter_mm","in":"query","required":true,"description":"Outer recorded diameter (mm)","schema":{"type":"string"},"example":"290"},{"name":"inner_diameter_mm","in":"query","required":true,"description":"Inner recorded diameter (mm)","schema":{"type":"string"},"example":"120"},{"name":"groove_pitch_um","in":"query","required":true,"description":"Groove pitch (µm)","schema":{"type":"string"},"example":"100"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"note":"Unrolled, the spiral groove is astonishingly long: its length ≈ the number of turns × the mean circumference (π × the average of the outer and inner diameters). A 12-inch LP side runs on the order of 400–500 metres of groove. The stylus traces this whole length once per side, which is why a tiny mistracking error repeated over half a kilometre of wall undulations is audible.","inputs":{"groove_pitch_um":100,"inner_diameter_mm":120,"outer_diameter_mm":290},"revolutions":850,"groove_length_m":547.42},"meta":{"timestamp":"2026-06-07T08:17:49.359Z","request_id":"908e7ebb-5ede-4481-9add-b1e38b0fdad4"},"status":"ok","message":"Groove length","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/groove-speed":{"get":{"operationId":"get_v1_groove_speed","tags":["Vinyl"],"summary":"Linear groove speed at a radius","description":"","parameters":[{"name":"rpm","in":"query","required":true,"description":"Turntable speed (rpm)","schema":{"type":"string"},"example":"33.333"},{"name":"radius_mm","in":"query","required":true,"description":"Radius on the disc (mm)","schema":{"type":"string"},"example":"145"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"note":"The linear speed the stylus sees = the angular speed × the radius (v = 2π × rpm/60 × r). On a constant-rpm record the outer grooves pass the stylus far faster than the inner ones — about 50 cm/s at the start of a 12-inch LP but only ~20 cm/s near the label. Less groove length per second at the inside means less room for detail, the cause of 'inner-groove distortion' and why engineers put quieter tracks last.","inputs":{"rpm":33.333,"radius_mm":145},"linear_speed_m_per_s":0.5061,"linear_speed_cm_per_s":50.61},"meta":{"timestamp":"2026-06-07T08:17:49.453Z","request_id":"ec7a6301-e3c6-4e92-8378-97f8e0e8d80d"},"status":"ok","message":"Groove speed","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/playing-time":{"get":{"operationId":"get_v1_playing_time","tags":["Vinyl"],"summary":"Playing time of a side","description":"","parameters":[{"name":"outer_diameter_mm","in":"query","required":true,"description":"Outer recorded diameter (mm)","schema":{"type":"string"},"example":"290"},{"name":"inner_diameter_mm","in":"query","required":true,"description":"Inner recorded diameter (mm)","schema":{"type":"string"},"example":"120"},{"name":"groove_pitch_um","in":"query","required":true,"description":"Groove pitch / spacing (µm)","schema":{"type":"string"},"example":"100"},{"name":"rpm","in":"query","required":true,"description":"Turntable speed (rpm)","schema":{"type":"string"},"example":"33.333"}],"security":[{"oanorKey":[]}],"responses":{"200":{"description":"OK","content":{"application/json":{"example":{"data":{"note":"A record's playing time = the number of groove turns ÷ the turntable speed. 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A tighter pitch fits more time but cuts the groove amplitude — and so the loudness and bass — which is the classic time-versus-level trade a cutting engineer makes.","inputs":{"rpm":33.333,"groove_pitch_um":100,"inner_diameter_mm":120,"outer_diameter_mm":290},"revolutions":850,"playing_time_min":25.5,"playing_time_formatted":"25:30"},"meta":{"timestamp":"2026-06-07T08:17:49.554Z","request_id":"a8571154-0550-4e70-a61a-86cc0615bcc8"},"status":"ok","message":"Playing time","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":"mm, µm, rpm. turns = (outer−inner)/2 ÷ pitch; time = turns/rpm; length = turns × π × mean diameter; speed = 2π·rpm/60·r. 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