Run your office football prediction league in one app

I want an app my team opens every week to run our office football prediction league, so the whole thing stops living in a spreadsheet. It reads fixtures and results from API-Sports and posts the table to Slack.

In settings I pick the competition and season the league runs on, for example the Premier League for the current season, plus the timezone everyone should see kickoff times in. Settings also holds the scoring rules: 3 points for an exact score and 1 point for the correct result by default, both editable. Store these settings in the app so they persist for the whole team.

The main screen is the current round. Use the API-Sports Get Fixture Rounds operation to find the round for the chosen league and season, then List Fixtures filtered to that league, season and round to load the matches. Always pass the timezone parameter so kickoff times match what the viewer expects. Show each match as a card with both teams, the kickoff time and the match status.

Under every fixture card, the signed-in person types a predicted score for the home team and the away team and saves it. A person's picks for a match lock at that match's kickoff time, so after kickoff the inputs are read-only for that match while matches later in the round stay editable. Before kickoff a prediction is visible only to the person who made it, so nobody can copy. Once a match has kicked off, everyone's prediction for that match becomes visible.

A results view re-reads the round with List Fixtures and scores every prediction. Only score matches whose status is finished, meaning FT, AET or PEN, and skip anything postponed, cancelled or still in progress. Award the exact-score points when both numbers match, otherwise the correct-result points when the predicted winner or draw matches, otherwise zero. Show each person's picks next to the real score with the points earned.

A season leaderboard ranks everyone by total points and includes a column for each of the last three rounds, so streaks and slumps are visible at a glance. Show position, name, the three recent round scores and the season total.

A button posts the current leaderboard to Slack. Use the Slack List Channels operation to let the person choose the destination channel, then Send a Message to post the table along with the biggest movers, meaning who climbed and who fell the most positions since the previous round. Format the message with Slack markup so it reads well in the channel.

Predictions, awarded points and the scoring rules all live in the app's own storage rather than a spreadsheet. Each person can only create and edit their own predictions and cannot touch anyone else's, while everyone can read the leaderboard and the results view.

The API-Sports free plan allows 100 requests a day, so fetch a round's fixtures once and cache them rather than calling per user or per page load. Refresh the cached fixtures when someone opens the results view after matches have finished. League standings from Get Standings are optional colour on the fixture cards, so only add them if the request budget allows.