Backend Study Games

Backend concept map

Use this map to connect games to the backend ideas they teach, then revisit weak concepts from your local review history.

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Your local concept signals

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Concepts

Each concept links to games, learning objectives, common mistakes, and local review items.

All games by concept

The same 15 games are preserved; the concept map simply gives them a study structure.

Auth Intermediate

Auth Token Inspector

Inspect authentication scenarios and choose safe backend decisions for tokens, scopes, sessions, CSRF, and object-level authorization.

Time
6-9 minutes
Concept
Authentication, authorization, sessions, and token safety
  • Foundations
  • Auth
  • JWT
  • sessions
Play Auth Token Inspector
APIs Beginner

API Route Builder

Design REST-style methods and routes for product requirements such as creating users, updating email, searching products, and nested comments.

Time
6-9 minutes
Concept
REST API route design
  • Foundations
  • REST
  • API design
  • routes
Play API Route Builder
Caching Beginner

Cache Eviction Lab

Predict cache hits and misses as requests flow through an LRU cache, then experiment with TTL behavior and stale data tradeoffs.

Time
5-8 minutes
Concept
Cache hits, misses, LRU, TTL, and stale data
  • Data & Performance
  • cache
  • LRU
  • TTL
Play Cache Eviction Lab
Reliability Intermediate

Circuit Breaker Clinic

Diagnose dependency failures and choose circuit breaker, timeout, fallback, retry, half-open, and bulkhead strategies that reduce blast radius.

Time
6-9 minutes
Concept
Circuit breakers, timeouts, retries, fallbacks, and dependency isolation
  • Production Reliability
  • resilience
  • circuit breaker
  • timeouts
Play Circuit Breaker Clinic
Reliability Intermediate

Idempotency Key Clinic

Diagnose retry scenarios and choose safe idempotency behavior for payments, emails, imports, orders, PUT updates, and scarce inventory.

Time
6-9 minutes
Concept
Idempotency, retries, duplicate prevention, and consistency
  • Production Reliability
  • Idempotency
  • Reliability
  • Consistency
Play Idempotency Key Clinic
APIs Intermediate

CORS Preflight Pilot

Guide browser API requests through CORS decisions covering origins, preflight, credentials, exposed headers, and cache safety.

Time
6-9 minutes
Concept
CORS, browser security boundaries, and preflight response design
  • Foundations
  • CORS
  • HTTP
  • browser security
Play CORS Preflight Pilot
APIs Beginner

HTTP Status Defender

Choose the correct HTTP status code for realistic backend scenarios and learn the response semantics behind each answer.

Time
5-8 minutes
Concept
HTTP status codes and response semantics
  • Foundations
  • HTTP
  • REST
  • status codes
Play HTTP Status Defender
Queues Intermediate

Message Queue Simulator

Tune workers, retries, and dead-letter behavior while jobs move through an async queue with failures and poison messages.

Time
7-11 minutes
Concept
Async jobs, retries, visibility timeout, and dead-letter queues
  • Production Reliability
  • queues
  • retries
  • dead-letter queue
Play Message Queue Simulator
Reliability Intermediate

Observability Incident Triage

Triage production incidents by choosing useful metrics, logs, traces, queue signals, database evidence, request ids, and alerting strategies.

Time
6-9 minutes
Concept
Production observability, incident triage, metrics, logs, traces, and alerts
  • Production Reliability
  • observability
  • incidents
  • metrics
Play Observability Incident Triage
Scaling Intermediate

Load Balancer Challenge

Route simulated traffic across backend servers using round robin, weighted round robin, least connections, and random strategies.

Time
6-10 minutes
Concept
Load balancing strategies
  • Production Reliability
  • load balancing
  • scaling
  • latency
Play Load Balancer Challenge
APIs Intermediate

Webhook Signature Forensics

Investigate webhook requests and choose safe handling for signatures, replay windows, retries, idempotency, and durable acknowledgement.

Time
6-9 minutes
Concept
Webhook verification, replay protection, idempotency, and retry-safe processing
  • Foundations
  • webhooks
  • HMAC
  • idempotency
Play Webhook Signature Forensics
Databases Advanced

Transaction Isolation Arena

Defend database invariants from concurrent requests by choosing transactions, locks, constraints, snapshot reads, and optimistic concurrency.

Time
7-10 minutes
Concept
Database transactions, isolation anomalies, locks, and invariant protection
  • Data & Performance
  • SQL
  • transactions
  • isolation
Play Transaction Isolation Arena
Scaling Intermediate

Rate Limit Architect

Choose rate limiting designs for realistic backend traffic patterns, from public APIs and login endpoints to queues, webhooks, and retry storms.

Time
6-9 minutes
Concept
Rate limiting, fairness, backpressure, and abuse protection
  • Data & Performance
  • Rate limiting
  • Scaling
  • 429
Play Rate Limit Architect
Databases Intermediate

SQL Index Quest

Choose the best database index for simplified schemas and queries while learning full scans, covering indexes, sort avoidance, and composite order.

Time
7-10 minutes
Concept
Database indexing and query performance
  • Data & Performance
  • SQL
  • indexes
  • performance
Play SQL Index Quest
Databases Intermediate

Schema Migration Runbook

Choose safe zero-downtime database migration steps for expanding schemas, backfilling data, rolling out indexes, enforcing constraints, and recovering from failures.

Time
6-9 minutes
Concept
Zero-downtime schema migration planning and expand-contract releases
  • Data & Performance
  • migrations
  • schema design
  • backfill
Play Schema Migration Runbook