#outdoor

Rock-climbing grade conversion as an API, computed locally and deterministically — the cross-system grade translations a climber, gym or guidebook app needs when the same route reads differently in every country. The route endpoint takes a roped-climbing grade in any major system — the American Yosemite Decimal System (5.5 to 5.15d), French sport grades (4b to 9c+), the UIAA scale used across Central Europe (IV to XIII-) or the Australian/New Zealand Ewbank numbers (12 to 40) — and returns the equivalents in all of them, so a 5.11a is a French 6c, a UIAA VII+ and an Ewbank 22. The boulder endpoint converts between the American V-scale (VB and V0 to V17) and the French Fontainebleau scale (3 to 9A), so a V5 is Font 6C and a problem graded 7A is about V6. You can pass a grade in any supported system and it finds the row and gives the rest — handy for syncing a tick list across regions or showing a climber a grade they recognise. Everything is computed locally and deterministically, so it is instant and private. Ideal for climbing, bouldering, gym, guidebook and outdoor-sports app developers, tick-list and route-database tools, and training-log software. Pure local computation — no key, no third-party service, instant. Chart equivalents — grades are inherently approximate across systems. Live, nothing stored. 2 conversion endpoints.

api.oanor.com/climbgrade-api

Archery and arrow maths as an API, computed locally and deterministically — the FOC, energy and arrow-weight numbers an archer or bowhunter tunes a setup with. The FOC endpoint finds the front-of-center balance, the share of an arrow’s weight that sits forward of the middle: FOC = ((balance point − length ÷ 2) ÷ length) × 100 measured from the throat of the nock, so a 28-inch arrow balancing at 16 inches is 7.1 % — and it bands the result, since target archers run about 7–12 % while hunters push 12–19 % for penetration and forgiveness. The energy endpoint turns arrow weight and speed into terminal performance: kinetic energy (ft-lb) = grains × fps² ÷ 450,240 and momentum (slug-fps) = grains × fps ÷ 225,218, so a 400-grain arrow at 280 fps carries about 69.7 ft-lb and 0.50 slug-fps, with a suggested game class — momentum, not KE, is the better penetration predictor for heavy arrows. The weight endpoint totals a finished arrow from its parts — shaft (grains-per-inch × length) plus point, insert, nock and fletching — and divides by draw weight for grains-per-pound, flagging the 5-GPP minimum that protects the bow. Everything is computed locally and deterministically, so it is instant and private. Ideal for archery, bowhunting, traditional-archery and outdoor-sports app developers, arrow-builder and bow-tuning tools, and pro-shop calculators. Pure local computation — no key, no third-party service, instant. Imperial archery units. Live, nothing stored. 3 compute endpoints. For sight marks or bow tuning use a different API.

api.oanor.com/archery-api