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
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), …
- REST API Design
- Idempotency
- Webhooks
API Design and GraphQL - 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…
- Precedent Transactions
- Acid
- Isolation Levels
Introduction to Database Systems - 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 Orchestration
- Network Policy
- Calico
Container Orchestration with Kubernetes - 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…
- Cnn Classification
- Cnn Architectures
- Transfer Learning
Deep Learning for Computer Vision Develop in-demand professional skills.
Each challenge names the skills it strengthens. Over time, your profile fills with the competences a hiring manager would actually look for.
Why Ewance
- 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 - DesignIntermediateNew
IT Architecture Overhaul for a 40-Person SaaS Scale-Up
Design a microservices-based architecture with multi-tenancy, API gateway, and compliance features. Propose a migration strategy (strangler fig pattern) over 12 months. Deliver …
- Microservices Patterns
- Multi Tenancy Architecture
- Multi Cloud Architecture
Information Systems and IT Management - 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
Knowledge Graphs and Semantic Web - 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 Orchestration
- Multi Tenancy Architecture
- AWS Or Azure
Cloud Computing - Browse challenges
Explore role
Strategy Analyst
Frame the business question, model the options, build the recommendation. From market sizing to competitive analysis, this role is where strategy consulting meets in-house decision-making.
- 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…
- REST API Design
- Graphql Federation
- REST API Design
API Design and GraphQL
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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