Glossary

Plain-English definitions for the terms you'll see across Who Play and the pickup-sports world.

Who Play is built around a small set of concepts: ELO ratings adapted for amateur sports, a season-archive cadence that resets monthly, automatic team balancing, and a few sport-specific terms. This glossary defines each one in plain English, in the same form a player or organiser would expect.

ELO rating: A relative skill-rating system originally invented by Arpad Elo for chess. Each player has a numeric rating that goes up when they beat stronger opponents and down when they lose to weaker ones. Who Play uses ELO across six sports — padel, futsal, soccer, tennis, basketball and volleyball — to keep amateur standings honest and to auto-balance teams before each game.
K-factor: The maximum rating change possible in a single game in an ELO system. Who Play uses K=32 as the base value: a moderate sensitivity that updates ratings noticeably after each game but doesn't whipsaw on a single unlucky result.
MVP vote: A one-tap post-match vote where each player picks the most valuable player of the game. Votes close automatically; the result shows on the post-match card and counts toward Player of the Month, which earns a small ELO bonus at season archive.
RSVP: A player's Yes / No / Maybe response to a game invitation. In Who Play, an RSVP can be confirmed without an account; only players who want to track stats or vote MVP need to sign in. RSVPs close on the deadline the organiser sets when creating the game.
Recurring game: A game that auto-creates on a weekly schedule — same day, same time, same venue. Who Play opens new RSVPs automatically and promotes players from the waitlist when a confirmed player drops. Ideal for groups who play every Tuesday or Sunday morning.
Waitlist: An automatic standby queue once a game's maximum players is full. If a confirmed player cancels, the next person on the waitlist is promoted automatically and notified. Keeps recurring games full without manual messaging.
Round-robin tournament: A tournament format where every player (or team) plays every other player exactly once. Who Play's Tournaments v1 supports round-robin brackets across a group, with a shared champions hero and automatic ELO updates for every match.
Monthly recap: A 9:16 Stories-format image generated once a month per group, summarising standings, MVPs, win streaks and attendance. Designed to be shared straight to Instagram or WhatsApp, the recap is what brings groups back when the season feels routine.
Pickup game: An informal sports session organised among friends or colleagues rather than a club or federation. Pickup games are typically peer-organised, flexible on dates and venues, and use loose rules. Who Play is built specifically for the pickup-game format.
Balanced teams: Automatically computed team pairings that minimise the ELO difference between sides. Once all players have RSVP'd Yes, Who Play splits the roster so the two teams have similar total skill. The organiser can override picks manually for guests or known injuries.
Season archive: The monthly rollover that locks the previous month's standings, applies small ELO bonuses for top finishers and the MVP of the month, then resets the leaderboard for a fresh month. Keeps long-term groups from getting stuck at the top or bottom of the table.
Padel: A racket sport for two pairs played on a smaller, walled court. Padel uses a perforated paddle and a slightly depressurised tennis ball, and walls are in play. It is one of the fastest-growing racket sports in Europe and one of the formats Who Play groups most often organise.
Futsal: A five-a-side indoor variant of soccer played on a hard court with a low-bounce ball. Games are shorter than full-pitch soccer (typically 2 × 20 minutes) and emphasise close ball control. Many Who Play groups play weekly futsal as their main sport.
Group invite link: A shareable URL that anyone can use to join a Who Play group without an account, then sign in only if they want to track stats. The link stays valid until the organiser rotates it. Use it instead of manually adding each player by email.
PWA (Progressive Web App): A web app that can be installed on iOS or Android directly from the browser, runs full-screen like a native app, and works offline for content that is already cached. Who Play ships as a PWA: no app-store wait, same codebase, same URL for sharing.

Last updated: May 12, 2026