Designing a Sports Betting Platform

Sports betting platforms must handle thousands of simultaneous bets on live events while managing financial risk in real-time.

Core Features

• Real-time odds updates (changes every few seconds)
• Bet placement with instant confirmation
• In-play (live) betting
• Risk management (limit exposure per outcome)
• Payout calculation and processing

Odds and Market Management

Market: Premier League — Arsenal vs Chelsea

Outcomes:
  Arsenal Win:  Odds 2.10 (implied prob 47.6%)
  Draw:         Odds 3.40 (implied prob 29.4%)
  Chelsea Win:  Odds 3.60 (implied prob 27.7%)

Margin: sum of implied probs > 100% = bookmaker profit

Architecture

Sports Data Feed (Opta, Stats Perform)
        ↓
  Odds Engine (recalculates on events)
        ↓
  Kafka (odds_updated topic)
        ↓
  WebSocket → All connected clients

Bet Placement:
  Client → Bet Service → Risk Engine
                              ↓
                    Accept / Reject / Limit
                              ↓
                       Wallet Service
                              ↓
                       Ledger DB

Risk Management

Exposure limits per outcome:
  Arsenal Win liability cap: $500,000

  Current liability = SUM(bet_amount × (odds - 1))
  for all Arsenal Win bets

  IF liability > cap:
    Shorten Arsenal odds (make less attractive)
    OR Refuse new Arsenal Win bets

In-Play Betting

Event: Arsenal scores at 67'
    ↓
Odds engine recalculates instantly
    ↓
All markets briefly suspended (3-5 seconds)
    ↓
New odds published
    ↓
Betting resumes

Latency requirement: <500ms from event to new odds

Bet Placement — Concurrency

-- Atomic bet placement
BEGIN;
  -- Deduct from wallet (prevent negative balance)
  UPDATE wallets
  SET balance = balance - :stake
  WHERE user_id = :user_id AND balance >= :stake;

  IF rows_affected = 0: ROLLBACK (insufficient funds)

  -- Record bet
  INSERT INTO bets (user_id, market_id, outcome, stake, odds);
COMMIT;

Payout Processing

Event result confirmed
    ↓
Query all winning bets for outcome
    ↓
payout = stake × odds
    ↓
Credit wallet (batch, async)
    ↓
Notify user

Conclusion

Sports betting requires sub-second odds recalculation, atomic bet placement, real-time exposure tracking, and instant payout processing — all while managing regulatory compliance.