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 Java EE REST API for the EcoThreads Marketplace
Using the EcoThreads operations file, the sample product catalog export, and the API requirements specification provided to you, design and implement a RESTful backend with Java…
- Java Ee
- REST API
- Jpa
Open coursework - 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
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 - DesignIntermediateNew
Counterfactual Explanations for an Insurance Pricing Model
You receive a trained LightGBM regression model (premium in GBP), the feature schema (28 features, 14 mutable from the customer's side), and 500 sample quotes. Use DiCE (Diverse…
- Counterfactual Explanations
- Dice Ml
- Interpretability
Open coursework 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
- 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 - DesignIntermediateNew
Resolve the Quota Double-Spend: Design Meterly's Order-Provisioning Schema
Working only from the materials provided, reach and defend a database design. Read the de-identified incident record (incident-file) and the business-rules brief (requirements-b…
- Transactions
- Acid
- Isolation Levels
Open coursework - DesignBeginnerNew
Design a Resilient Bridge Between New Commerce and Legacy SAP
Using the integration requirements case file, design how all five interactions move between the storefront and SAP ECC: order create, pricing inquiry, inventory availability, cr…
- Enterprise Integration
- SAP Integration
- Apache Camel
Open coursework - 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 - 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.
- DesignBeginnerNew
Design the Architecture for a Library Management System
Read the 30-page replacement RFP. Author a 15-page architecture document covering the C4 model levels 1-3 (context, container, component) for the new system: web app, mobile app…
- Software Architecture
- C4 Model
- Data Modeling
Open coursework - DesignIntermediateNew
Build a Multi-Tenant Kubernetes Foundation for Veterinary-Clinic SaaS
Using the provided tenant tier specification and tenant roster, design and prototype a multi-tenant model where each tenant gets its own Kubernetes namespace for compute, its ow…
- Kubernetes
- Multi Tenancy
- AWS
Open coursework - 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 - 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 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 6TB Social-Commerce Database to a Sharded Topology
Using the supplied schema specification and the seven-day anonymized query-workload export, decide the correct shard key for each table and justify it from observed access patte…
- Database Sharding
- Postgresql
- Vitess
Open coursework - 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 - 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
Open coursework - 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 - 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 - StrategyIntermediateNew
Stand Up Contract Testing for a Logistics Microservices Backend
Using only the materials provided, choose and justify the six producer-consumer service pairs to migrate first. Read the 90-day staging breakage log to rank pairs by how much pa…
- Contract Testing
- Pact
- Microservices
Open coursework - CodeSeniorNew
Envoy WASM Filter for Per-Tenant Rate Limiting
Implement the filter in Rust using the proxy-wasm-rust-sdk. The filter computes a (tenant_id, endpoint, method) key, calls a Redis token-bucket service via a sidecar HTTP client…
- Envoy
- Wasm
- Rust Programming
Service Mesh and Microservices Networking - CodeIntermediateNew
Design Prompt Versioning and Observability for a Coding Assistant
You will (1) design a prompt-registry data model (versions, owners, environments, change log) and implement it in Postgres + a small Python SDK, (2) instrument the assistant to …
- Prompt Versioning
- Observability
- Pii Scrubbing
LLM Application Development - CodeBeginnerNew
REST API + Admin Dashboard for a Tutoring Marketplace
Map the 5 operator workflows by shadowing 2 operators for 4 hours (recordings provided). Design REST endpoints (Open API spec) covering each workflow with role-based scopes (ope…
- REST API
- Vuejs
- Rbac
Web Application Development - DesignIntermediateNew
Design a Region-Routed Storage Layer for a Nordic EdTech
Working only from the materials in this file, produce a recommendation for how Lärnova should store student assignments so each country's data stays in its home region. Start by…
- Geo Distribution
- Data Residency
- Cockroachdb
Open coursework - CodeBeginnerNew
Build a Product Knowledge Graph for a Fast-Fashion Retailer
You receive 200 sample SKUs across 4 markets (Spain, Germany, Japan, Brazil) as CSVs with country-specific attribute names. Design an OWL ontology with shared classes for Produc…
- Knowledge Graphs
- Owl Ontology
- Rdf
Open coursework 
CodeIntermediateNewDrift-Detect and Self-Heal a Multi-Tenant Kubernetes Estate
Using the estate-case-file and the baseline-policy-spec, design a drift-detection and self-heal rollout for all 28 single-customer clusters built on ArgoCD continuous-sync (auto…
- Argocd
- Kyverno
- Drift Detection
Open coursework
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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