Server and Client Side - How They Interact
Introduction
The architecture of online casinos is based on the clarity of the division of responsibilities between the client (frontend) and server (backend) parts. The client is responsible for interface display, user input and basic validation, the server for game logic, data storage, security and integration with external services. The effectiveness of their interaction directly affects the responsiveness, stability and reliability of the platform.
1. Main components of the client side
1. UI/UX layer
HTML/CSS/JavaScript (React, Vue. js, Angular) for rendering game tables, machines, statistics.
WebAssembly for high-performance browser-side logic (for example, fast 3D graphics rendering).
2. Condition management
Redux, Vuex or contextual APIs for storing session, rates and current results.
3. Communication modules
WebSocket client (Socket. IO, native WebSocket API) for real-time updates: spin result, balance changes, chats.
HTTP client (fetch, Axios) for profile REST requests, transaction history, resource downloads.
4. Security on the client
Encrypting sensitive data (for example, using the Web Crypto API).
Validation of input data before sending (card entry forms, bet amount).
2. Main components of the server part
1. API layer
REST (Express. js, Spring Boot, ASP. NET Core) and/or gRPC for data exchange: authorization, balance, game histories, bonuses.
WebSocket server for instant transmission of game events and notifications.
2. Game logic
Pseudo-random number generation (RNG module in C++ or Rust) with certification and audit.
Business rules: checking bets, calculating winnings, managing rounds.
3. Data warehouses
Relational databases (PostgreSQL, MySQL) for accounting profiles, transactions, bid history.
NoSQL (Redis, MongoDB) for caching sessions, fast leaderboard tables, storing episodic information.
4. Integration
Payment gateways (REST/Webhooks) for deposit and withdrawal.
Game providers (SDK modules, APIs) for connecting ready-made slot machines and tables.
3. Interaction protocols
1. HTTP/HTTPS и REST
Requests for authorization, work with balance, transaction history.
JSON-payload; JWT or session cookies for authentication.
2. WebSocket
Persistent bidirectional connection for instant updates:
High-performance binary serialization for microservices inside the backend.
4. Webhooks
Asynchronous alerts from external services (payment providers, KYC/AML).
4. Request-Response Sequence
1. Connection and authorization
The client sends POST/auth/login → the server checks credentials → returns a JWT + WebSocket-token.
The client establishes a WebSocket connection with a token transfer.
2. Game Content Request
GET/games/list → the server gives a JSON list of available games with metadata (name, bet, RTP).
3. Round initiation
Client via WebSocket: '{action: "spin," gameID:42, bet: 1. 5} '→ the server checks the balance, reserves the bet.
4. Result generation
The RNG module gives out numbers, the server calculates payments, updates the balance in the database.
5. Sending the result
The server sends a response via WebSocket: '{result: [...], payout: 3. 0, balance: 102. 5 }`.
6. Logging and analytics
Each event is fluffed in Kafka/Elasticsearch for subsequent processing and monitoring.
5. Provides low latency and scalability
1. Caching
Redis to store frequently requested data (currency rates, game settings, static).
2. Load balancing
NGINX/HAProxy before WebSocket clusters and REST services.
3. Sharding and Replication
Horizontal database sharding by region or transaction volume.
Replication for fault tolerance.
4. Microservices and containers
Each domain (games, payments, users) in its own container (Docker + Kubernetes) with auto-scaling.
6. Security of communications
TLS/SSL on all channels (HTTPS, WSS).
Digital signatures of WebSocket messages to prevent spoofing.
Rate limiting and DDoS protection at the WAF (ModSecurity) level.
Regular penetration tests and RNG module code audit.
7. Logging and interaction monitoring
Metrics (Prometheus): API response time, spin session duration, throughput WebSocket.
Logs (ELK stack): request-response tracing, authorization errors, unsuccessful transactions.
Alerts in Slack/Email for p99-latency drops above 200 ms or 5xx errors.
Conclusion
Architecturally correct separation of the client and server parts ensures a smooth user experience, security and the ability of the platform to withstand constant peak loads. Key principles: using WebSocket for real-time exchange, REST/gRPC for data requests, strong authentication and encryption, distributed caching and automatic scaling. Following these recommendations, developers create fast, reliable and flexible solutions for the online casino industry.
The architecture of online casinos is based on the clarity of the division of responsibilities between the client (frontend) and server (backend) parts. The client is responsible for interface display, user input and basic validation, the server for game logic, data storage, security and integration with external services. The effectiveness of their interaction directly affects the responsiveness, stability and reliability of the platform.
1. Main components of the client side
1. UI/UX layer
HTML/CSS/JavaScript (React, Vue. js, Angular) for rendering game tables, machines, statistics.
WebAssembly for high-performance browser-side logic (for example, fast 3D graphics rendering).
2. Condition management
Redux, Vuex or contextual APIs for storing session, rates and current results.
3. Communication modules
WebSocket client (Socket. IO, native WebSocket API) for real-time updates: spin result, balance changes, chats.
HTTP client (fetch, Axios) for profile REST requests, transaction history, resource downloads.
4. Security on the client
Encrypting sensitive data (for example, using the Web Crypto API).
Validation of input data before sending (card entry forms, bet amount).
2. Main components of the server part
1. API layer
REST (Express. js, Spring Boot, ASP. NET Core) and/or gRPC for data exchange: authorization, balance, game histories, bonuses.
WebSocket server for instant transmission of game events and notifications.
2. Game logic
Pseudo-random number generation (RNG module in C++ or Rust) with certification and audit.
Business rules: checking bets, calculating winnings, managing rounds.
3. Data warehouses
Relational databases (PostgreSQL, MySQL) for accounting profiles, transactions, bid history.
NoSQL (Redis, MongoDB) for caching sessions, fast leaderboard tables, storing episodic information.
4. Integration
Payment gateways (REST/Webhooks) for deposit and withdrawal.
Game providers (SDK modules, APIs) for connecting ready-made slot machines and tables.
3. Interaction protocols
1. HTTP/HTTPS и REST
Requests for authorization, work with balance, transaction history.
JSON-payload; JWT or session cookies for authentication.
2. WebSocket
Persistent bidirectional connection for instant updates:
- Beginning and end of the game round.
- Push notifications about balance changes and bonus status.
- 3. gRPC (optional)
High-performance binary serialization for microservices inside the backend.
4. Webhooks
Asynchronous alerts from external services (payment providers, KYC/AML).
4. Request-Response Sequence
1. Connection and authorization
The client sends POST/auth/login → the server checks credentials → returns a JWT + WebSocket-token.
The client establishes a WebSocket connection with a token transfer.
2. Game Content Request
GET/games/list → the server gives a JSON list of available games with metadata (name, bet, RTP).
3. Round initiation
Client via WebSocket: '{action: "spin," gameID:42, bet: 1. 5} '→ the server checks the balance, reserves the bet.
4. Result generation
The RNG module gives out numbers, the server calculates payments, updates the balance in the database.
5. Sending the result
The server sends a response via WebSocket: '{result: [...], payout: 3. 0, balance: 102. 5 }`.
6. Logging and analytics
Each event is fluffed in Kafka/Elasticsearch for subsequent processing and monitoring.
5. Provides low latency and scalability
1. Caching
Redis to store frequently requested data (currency rates, game settings, static).
2. Load balancing
NGINX/HAProxy before WebSocket clusters and REST services.
3. Sharding and Replication
Horizontal database sharding by region or transaction volume.
Replication for fault tolerance.
4. Microservices and containers
Each domain (games, payments, users) in its own container (Docker + Kubernetes) with auto-scaling.
6. Security of communications
TLS/SSL on all channels (HTTPS, WSS).
Digital signatures of WebSocket messages to prevent spoofing.
Rate limiting and DDoS protection at the WAF (ModSecurity) level.
Regular penetration tests and RNG module code audit.
7. Logging and interaction monitoring
Metrics (Prometheus): API response time, spin session duration, throughput WebSocket.
Logs (ELK stack): request-response tracing, authorization errors, unsuccessful transactions.
Alerts in Slack/Email for p99-latency drops above 200 ms or 5xx errors.
Conclusion
Architecturally correct separation of the client and server parts ensures a smooth user experience, security and the ability of the platform to withstand constant peak loads. Key principles: using WebSocket for real-time exchange, REST/gRPC for data requests, strong authentication and encryption, distributed caching and automatic scaling. Following these recommendations, developers create fast, reliable and flexible solutions for the online casino industry.
