$MOEDADA is a web platform for heads-or-tails duels: one player challenges another, both bet fictional points, the coin is flipped on the server round by round, and the result feeds a global ranking. It is a solo project built during the Systems Development technical course at SENAI, from the requirements specification to delivery. The interface is in Portuguese.

Features

• Accounts: sign up, login and logout, with 1,000 starting points for each player.
• Challenge CRUD: create, list with opponent search and status filter, edit and cancel.
• Accept or decline: the opponent decides whether to take the challenge.
• Duels of 3, 5 or 10 rounds, with bets from 10 to 1,000 points.
• Arena that flips the coin without reloading the page, with round history.
• Automatic settlement: points only change hands when the duel ends.
• Global ranking by wins and by points.

Technical highlights

• Server-side draw with random_int(): the browser only requests the flip and shows the result.
• Consistency under concurrency: each flip runs in a transaction that locks the challenge with SELECT ... FOR UPDATE, and a unique key prevents duplicate rounds.
• Security: PDO with prepared statements, CSRF tokens on every form and on the API, passwords with password_hash(), session regeneration on login and escaped output against XSS.
• Engineering documentation: specification with 19 functional requirements, 16 non-functional requirements and 18 business rules, architecture with 12 recorded decisions, a test plan with 25 test cases and its own design system.

Stack

• PHP 7.4+ with PDO
• MySQL 8
• Bootstrap 5 with custom CSS
• JavaScript (fetch)