Computer Science
Backend & API Development Challenges
Backend & API Development challenges put you behind the systems that power every product, where you design the contracts other teams build on. You'll work through REST API Design and HTTP Fundamentals, build services with FastAPI, model data with GraphQL schema design, and harden access with OAuth 2.0 / JWT.
From there you'll handle the harder edges — API security (OWASP API Top 10), rate limiting, API versioning, multi-tenancy architecture, and API gateway patterns (Kong, Envoy) — the way platform teams actually run them in production. Each challenge you solve earns a verified credential you can share with recruiters.
- CodeIntermediateNew
Build a GraphQL Federation Schema for an E-Commerce Platform
Receive the existing 22 REST endpoints' OpenAPI specs and a list of 5 priority subgraphs. Design a federated GraphQL schema using Apollo Federation v2 directives (@key, @externa…
- Graphql
- Graphql Federation
- API Design
API Design and GraphQL - CodeIntermediateNew
Add Idempotency Keys to a Payment Webhook System
Read the current Go webhook-sender code and 30 days of duplicate-delivery incident logs. Design the idempotency scheme: server-generated key per event (UUID v7 — time-ordered), …
- API Design
- Idempotency
- Webhooks
API Design and GraphQL - DesignIntermediateNew
Design Schema Evolution for a Multi-Tenant Event Platform
Design a schema-evolution model covering: schema-registry topology (per-tenant subjects vs shared), compatibility modes per topic class (strict vs forward-only vs none), tenant-…
- Schema Evolution
- Kafka
- Schema Registry
Event-Driven Architecture - DesignIntermediateNew
Build a Multi-Tenant SaaS Foundation on Kubernetes
Design the multi-tenant model: namespace-per-tenant for compute isolation, per-tenant Postgres schemas inside a shared RDS instance for data, per-tenant S3 prefixes with bucket …
- Kubernetes
- Multi Tenancy
- AWS
Cloud Computing Practice your coursework on real scenarios.
Every challenge is shaped from real-world context — not generic exercises. The work mirrors what your degree prepares you for.
Why Ewance
- DesignBeginnerNew
Design a Production HTTP/2 Load Balancer Configuration
Design a multi-region topology: anycast edge -> regional Envoy clusters -> origin services. Specify HTTP/2 connection pooling (max connections per upstream, idle timeout), retry…
- Application Protocols
- Load Balancing
- Envoy
Computer Networks - CodeBeginnerNew
Build a Booking Web App for a Boutique Hotel Group
Design the data model (properties, rooms, availability, bookings, guests). Build the Next.js app with the App Router: 4 public pages (search, results, room detail, checkout), 1 …
- Nextjs
- React
- REST API
Web Application Development - DesignIntermediateNew
Design a Geo-Distributed Storage Layer for an EdTech
Map the access patterns (90 percent reads from the country of origin, 10 percent cross-country via teacher reviewers). Design region routing using a metadata service backed by a…
- Geo Distribution
- Data Residency
- Cockroachdb
Distributed Systems - DesignIntermediateNew
Design a Transactional Schema for a SaaS Order-Provisioning System
Design the schema for orders, quota packs, consumption events, and refunds. Define each critical transaction (buy, consume, refund) with isolation level and locking strategy. Id…
- Transactions
- Acid
- Isolation Levels
Introduction to Database Systems - Browse challenges
Explore role
Product Manager
Ship product that solves real user problems. Combine user research, prototyping, and stakeholder alignment to turn ambiguous briefs into measurable wins — the role at the centre of modern software teams.
- AnalysisBeginnerNew
Developer-Experience Audit of a Public API
Walk through the existing public API as a first-time developer using only the public docs, OpenAPI spec, SDKs (Python + JavaScript), and example repos. Run the first-hour test 3…
- Developer Experience
- API Design
- Documentation
API Design and GraphQL - CodeBeginnerNew
Observability Injection: Distributed Tracing via Sidecars
Enable Envoy tracing with the OpenTelemetry tracer in Istio MeshConfig. Configure a Tempo backend with a Grafana frontend. Verify W3C tracecontext propagation across all 26 serv…
- Distributed Tracing
- Opentelemetry
- Envoy
Service Mesh and Microservices Networking - CodeIntermediateNew
Migrate an Internal Service from REST to gRPC
Receive the existing OpenAPI spec, the Go service code, and 7 days of traffic data. Pick the top 2 RPS-by-method endpoints and design Protocol Buffers (protobuf) message + servi…
- Grpc
- Protobuf
- API Design
API Design and GraphQL - CodeIntermediateNew
Ship a Streaming RAG Endpoint with Caching and Fallbacks
You will build a FastAPI service exposing one POST /chat endpoint that (1) streams tokens via Server-Sent Events, (2) caches identical (system_prompt, query, retrieved_context) …
- LLM API Integration
- Streaming
- Response Caching
LLM Application Development Build a verifiable portfolio.
Submissions become evidence. Reviewers with shipping experience score against a rubric; the result becomes a credential anyone can verify.
Why Ewance
- DesignIntermediateNew
Migrate a Monolithic Database to a Sharded Topology
Analyze schema (32 tables) + query workload (anonymized 7-day pg_stat_statements export) to identify the right shard key per table. Most tables shard on user_id; identify the 4-…
- Database Sharding
- Postgresql
- Vitess
Distributed Systems - DesignIntermediateNew
Drift-Detect + Self-Heal a Multi-Tenant Kubernetes Estate
Enable ArgoCD auto-sync with selfHeal + prune across all 28 clusters. Add Kyverno cluster policies enforcing baseline standards (registry, resource limits, network policy). Buil…
- Argocd
- Kyverno
- Drift Detection
GitOps and Continuous Delivery - AnalysisIntermediateNew
Audit API Governance Across a Tier-1 Bank's Integration Estate
Inventory the API estate using a combination of Swagger/OpenAPI scrapes (where present) and stakeholder interviews. Build a scorecard covering: spec completeness, auth scheme, v…
- API Governance
- Openapi Spec
- Dora Compliance
Enterprise and Business Software Engineering - AnalysisBeginnerNew
GDPR Article 25 Privacy-By-Design Review for a HealthTech API
Review the API specification (OpenAPI 3, provided, 42 endpoints). For each endpoint: identify data categories handled (special-category health data, identifiers, traffic data), …
- GDPR
- Privacy By Design
- API Design
Privacy-Enhancing Technologies - StrategyIntermediateNew
Migrating from Relational to NoSQL for a Social Media Startup
You are given a simplified relational schema of SnapVibe's current database (users, posts, comments, likes). Your task is to: (1) analyze the limitations of the relational model…
- Nosql
- Mongodb
- Data Migration
Database Systems - CodeIntermediateNew
Stand Up Contract Testing for a Microservices Backend
Inventory the 18 services and pick the 6 producer-consumer pairs with the most staging breakages in the last 90 days. Stand up a Pact broker (self-hosted or PactFlow trial). For…
- Contract Testing
- Pact
- Microservices
Software Testing and Quality Assurance - CodeBeginnerNew
Build a Crop-Disease Classifier for a Smallholder Agritech Startup
You receive a curated 22,000-image cassava-disease dataset across 5 classes (4 diseases + healthy) plus a labeled 1,200-image held-out test set. Train a CNN classifier (start wi…
- Image Classification
- Cnn Architectures
- Transfer Learning
Deep Learning for Computer Vision - DesignIntermediateNew
Design Multi-Tenant Network Policies with Calico Tier Enforcement
Receive the cluster topology (120 customer namespaces + 4 platform namespaces), the application traffic patterns (frontend talks to backend talks to its tenant's database), and …
- Kubernetes
- Network Policy
- Calico
Container Orchestration with Kubernetes - StrategyBeginnerNew
REST API Versioning Strategy for a 4-Year-Old Public API
Pick a versioning scheme (URI path vs header-based) and justify it against integrator behavior. Define the deprecation lifecycle: announce → deprecate → sunset, with concrete ti…
- REST API Design
- API Versioning
- Openapi
Engineering Software as a Service - DesignIntermediateNew
Design a Versioning Strategy for a Public REST API
Receive the OpenAPI spec for the 14 endpoints, 8 months of partner-support tickets tagged 'breaking-change', and the partner-mix breakdown (which endpoints which partner uses). …
- API Design
- REST
- API Versioning
API Design and GraphQL - CodeBeginnerNew
Build a Protein Structure Search and Visualization Tool
Build a FastAPI backend wrapping Foldseek's easy-search command, returning top-20 hits with alignment metadata. Build a React frontend with a structure upload widget and a 3D vi…
- Biomolecular Structure
- Bioinformatics
- Full Stack Development
Computational Biology and Health Informatics - DesignIntermediateNew
Design an Idiomatic REST + Webhooks API for a Logistics SaaS
Read the team's draft + the public APIs of 3 reference logistics platforms (anonymized, briefing pack provided). Author a 5-page API design guideline covering URL structure (nou…
- API Design
- REST
- Openapi
Software Design and Design Patterns
How it works
From brief to credential, in six steps.
Step 01
Browse challenges aligned to your studies.
Step 02
Accept the one that fits your goals.
Step 03
Work through it with AI Copilot guidance.
Step 04
Submit for structured evaluation.
Step 05
Earn a verified credential.
Step 06
Add it to LinkedIn with one click.
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