# Fieldday > Fixtures, brackets, ratings and training plans for your club — in one workspace. Fieldday is a free workspace for club organisers, coaches and captains. Keep one roster and run Americano or Mexicano nights, tournament brackets, a league with title odds and what-if scenarios, Elo and Glicko-2 ratings fed by every scored match, away-trip fatigue and jet-lag plans, running and strength training plans and a shared calendar. Nine usefulweb tools do the maths; Fieldday connects them, keeps the history and turns it into a club report. Fieldday (Sports club & training organiser) is a premium app of usefulweb.site (https://usefulweb.site/): a full program that runs in the browser. Its engine is deterministic and the same functions are exposed as tools, so an agent can compute exactly what the app shows. ## Use it - Landing page: https://fieldday.usefulweb.site/ - Workspace (browser app): https://fieldday.usefulweb.site/app - open a project with https://fieldday.usefulweb.site/app#project= or a template with https://fieldday.usefulweb.site/app#template= - Project file format (JSON Schema): https://fieldday.usefulweb.site/project.schema.json - Tutorials: https://fieldday.usefulweb.site/tutorials - JSON API: POST https://fieldday.usefulweb.site/api/v1/tools//calculate (catalog: https://fieldday.usefulweb.site/api/v1/tools) - OpenAPI: https://fieldday.usefulweb.site/openapi.json - MCP (Streamable HTTP): https://fieldday.usefulweb.site/mcp ## Engine tools - [Padel & Pickleball Scheduler](https://padelpickleballscheduler.usefulweb.site/): Fair Americano or Mexicano doubles rounds with balanced sit-outs, scores and standings. API: POST https://fieldday.usefulweb.site/api/v1/tools/padel-pickleball-scheduler/calculate · MCP tool `padel_pickleball_scheduler` - [Tournament Bracket Maker](https://tournamentbracketmaker.usefulweb.site/): Single or double elimination or round robin: seeded brackets, byes, results and downloads. API: POST https://fieldday.usefulweb.site/api/v1/tools/tournament-bracket-maker/calculate · MCP tool `tournament_bracket_maker` - [Elo/Glicko Rating Lab](https://eloglickoratinglab.usefulweb.site/): Rate players from game results with Elo, Glicko-1 and Glicko-2; history chart and win odds. API: POST https://fieldday.usefulweb.site/api/v1/tools/elo-glicko-rating-lab/calculate · MCP tool `elo_glicko_rating_lab` - [Sports What-If Simulator](https://sportswhatifsimulator.usefulweb.site/): Simulate a match or a small league with a Poisson goal model — and replay “what if”. API: POST https://fieldday.usefulweb.site/api/v1/tools/sports-what-if-simulator/calculate · MCP tool `sports_what_if_simulator` - [Sports Travel-Fatigue Estimator](https://sportstravelfatigueestimator.usefulweb.site/): Travel distance, time-zone jumps, rest and back-to-backs per game as a fatigue score. API: POST https://fieldday.usefulweb.site/api/v1/tools/sports-travel-fatigue-estimator/calculate · MCP tool `sports_travel_fatigue_estimator` - [Running Pace & Splits](https://runningpacecalculator.usefulweb.site/): Pace, time or distance in km or miles, splits, race predictions, treadmill speed, laps. API: POST https://fieldday.usefulweb.site/api/v1/tools/running-pace-calculator/calculate · MCP tool `running_pace_calculator` - [One-Rep-Max & Plate Loader](https://onerepmaxcalculator.usefulweb.site/): 1RM from any set (7 formulas + average), % and RPE tables, and which plates to load. API: POST https://fieldday.usefulweb.site/api/v1/tools/one-rep-max-calculator/calculate · MCP tool `one_rep_max_calculator` - [Random Generator](https://randomgenerator.usefulweb.site/): Random numbers, dice, coins, list picks, shuffles, fair teams, dates, strings and UUIDs. API: POST https://fieldday.usefulweb.site/api/v1/tools/random-generator/calculate · MCP tool `random_generator` - [Jet Lag Planner](https://jetlagplanner.usefulweb.site/): A day-by-day sleep, light and caffeine plan to beat jet lag, with calendar export. API: POST https://fieldday.usefulweb.site/api/v1/tools/jet-lag-planner/calculate · MCP tool `jet_lag_planner` ## Formats - Import: Fieldday project (.fieldday.json), Player list (CSV/TSV or one name per line), Player table from another premium app (App Bridge), Project link (#project=…) - Export: Fieldday project (.fieldday.json), CSV: roster, schedules, standings, fixtures, ratings, training tables, Bracket as SVG and PNG, iCalendar (.ics) with reminders, Jet-lag plan (.ics), Printable club report (PDF via print), Share link ## Limits - Fieldday is an organiser, not a booking system: no online sign-ups, payments, messaging or member logins. - Tools run on the usefulweb server: without a connection you can edit and view saved results but not run new calculations. - Mixer nights are doubles only (4 players per court); singles ladders go through tournaments and the game log. - One rating run uses the latest 200 games and at most 100 starting ratings; older games stay in the log. - The league simulator handles up to 16 teams and 240 fixtures with a Poisson goal model (football-style scores). - Travel fatigue knows 118 major sports cities; other venues need latitude,longitude and a time zone. - Training plans cover running paces and barbell percentages; there is no heart-rate, GPS or wearable import. - Calendar files are exported, not synced: re-export after changes.