Computer Science
Database & Storage Challenges
Database & Storage challenges put you inside the work of designing data layers that stay fast and correct under load. You'll develop skills in Data Modeling, Database Schema design, and Domain Modeling, and you'll write SQL with JOINs & Aggregations against PostgreSQL or MySQL.
From there you'll handle the harder edges — Indexing strategy, Query optimization, Replication basics, and Multi-region writes — working through High availability & disaster recovery and Oracle database administration the way data teams actually do. Each challenge you solve earns a verified credential you can share with recruiters.
Recommended Challenges
- ResearchSeniorNew
SAT-Based Planner for Smart-Grid Demand Response
Encode the dispatch problem (which customers to curtail by how much, respecting per-customer contractual caps and grid-cell totals) as a SAT or MaxSAT instance. Solve 50 histori…
- Sat Based Planning
- Constraint Encoding
- Benchmarking
Automated Planning - 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 - CodeIntermediateNew
Hierarchical Plans for an Aerospace Maintenance Crew Scheduler
You receive a synthetic week of 80 work orders with hierarchical decompositions, technician certifications, and shared-tool constraints. Implement an HTN planner (PyHOP or HDDL …
- Htn Planning
- Domain Modeling
- Constraint Handling
Automated Planning - CodeIntermediateNew
Tame Lock Contention on a Shared Property-Manager CRM Database
Working only from the four provided materials, produce a fix-and-prove package. Start with the recorded lock snapshots (lock_snapshots) and the environment case file (db_environ…
- Concurrency Control
- Lock Contention
- Postgresql
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
- CodeIntermediateNew
Build an Indexer for an On-Chain DeFi Analytics Product
Receive the 6 protocols' ABIs + the team's required event coverage spec (around 40 event types). Build a TypeScript indexer using viem + Postgres: subscribe to new blocks via We…
- Blockchain Indexing
- Typescript
- Ethereum
Blockchain and Decentralized Systems Engineering - AnalysisBeginnerNew
Plan and Validate a MySQL-to-PostgreSQL Records Migration
Using the de-identified case record (incident-file-records-office), the representative schema export (mysql-schema-sample), and the anonymized staging extract (staging-records-s…
- Database Migration
- Mysql
- Postgresql
Open coursework - CodeIntermediateNew
Design a Change-Data-Capture Pipeline for an E-Commerce Reseller
Receive the MySQL schema (220 tables), 7 days of binlog samples, and the data team's freshness + correctness requirements. Design the CDC pipeline: Debezium for MySQL binlog cap…
- Change Data Capture
- Debezium
- Kafka
Big Data and Data-Intensive Systems - DesignFoundationalNew
Redesign a Vet-Clinic SaaS Database to Third Normal Form
Using the current schema dump and the eight most-common reporting queries provided to you, design a replacement database structure for VetLedger. First, produce an entity-relati…
- Data Modeling
- Normalization
- SQL
Open coursework - 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
Author a Ubiquitous-Language Glossary for a Telco Billing Domain
Conduct 12 structured interviews (30 min each) with stakeholders across CRM, billing, AR, customer portal, and finance. Capture each team's terminology for the top 25 domain con…
- Ubiquitous Language
- Context Mapping
- Stakeholder Interviews
Domain-Driven Design - StrategyIntermediateNew
Decompose a CRM Monolith into Bounded Services
Analyze the monolith using NDepend or similar (provided). Identify the top 4-6 candidate service boundaries based on coupling + business-capability seams (likely: Quotation, Pol…
- Strangler Fig Pattern
- Service Decomposition
- Csharp Programming
Enterprise and Business Software Engineering - CodeIntermediateNew
Apply Hexagonal Architecture to a Payments Microservice
Design the settlement domain in pure Kotlin (no Spring imports, no framework annotations). Define ports for: payment-network adapter (one inbound per network — SEPA, Faster Paym…
- Hexagonal Architecture
- Ports And Adapters
- Kotlin Programming
Domain-Driven Design - DesignIntermediateNew
Design a Real-Time Order Pipeline for a Fintech Payments Platform
You receive a synthetic Kafka stream of around 500 transactions per second, a static merchant dimension table (about 80,000 rows), and a daily FX rate snapshot. Design an end-to…
- Streaming Data
- Kafka
- Stream Processing
Data Engineering and Big Data Systems 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
- AnalysisBeginnerNew
Index a Slow 90-Million-Row FinTech Reporting Database
Your analysis task is to read the engineering ticket and the six reporting queries in the case file (M1), study the transactions table definition, column statistics, and write w…
- Indexing
- Query Optimization
- Explain Analyze
Open coursework - CodeIntermediateNew
Design an Event-Sourced Inventory System for a Third-Party Warehouse
Working from the operations case file and the warehouse domain specification, design an event model of twelve to fifteen events that covers the warehouse lifecycle (receive, put…
- Event Sourcing
- Cqrs
- Eventstoredb
Open coursework - CodeIntermediateNew
Migrate a Legacy Warehouse to a Lakehouse for an Edtech AI Platform
You receive a Postgres dump of around 50 GB and the current dbt models that produce the student-attempts mart. Land the raw data in object storage (S3 or GCS) as Parquet partiti…
- Lakehouse Architecture
- Delta Lake
- Spark
Data Engineering and Big Data Systems - DesignSeniorNew
Designing a Data Warehouse for a Renewable Energy Firm
You are given sample data from three sources: energy production logs, weather data, and equipment maintenance records. Your task is to: (1) design a star schema with fact and di…
- Data Warehousing
- Star Schema
- Etl
Database Systems - AnalysisSeniorNew
Diagnose and Fix Query-Planner Misestimates in a FinTech Warehouse
For each of the 6 queries, capture EXPLAIN (ANALYZE, BUFFERS) and compare estimated vs actual rows at each node. Identify the misestimate source per query (single-column stats s…
- Query Optimization
- Postgresql Planner
- Extended Statistics
Advanced Database Systems - 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 - CodeIntermediateNew
Multi-Tenant SaaS Backend with Postgres Row Security
Design the multi-tenant schema: shared tables with a tenant_id column, indexed appropriately. Write a forward + backward migration (using Drizzle or Prisma). Implement Postgres …
- Multi Tenant Architecture
- Postgresql
- Row Level Security
Open coursework - 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
Plan Warehouse Pick Routes with a Classical Planner
You receive a stylized warehouse map (aisle graph), 30 sample shifts of pick tasks, and the current heuristic's outputs. Write a PDDL domain + problem generator, solve with at l…
- Pddl Modeling
- State Space Search
- Classical Planning
Open coursework - DesignBeginnerNew
Optimizing Inventory for a Toronto D2C Cosmetics Brand
Your task is to design a multidimensional data model (star schema) for inventory management, create an ETL pipeline to load sample data (provided as CSV files), and develop an O…
- Data Warehousing
- Etl
- Olap
Open coursework - 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
Open coursework - CodeIntermediateNew
Design an Anti-Corruption Layer for a Legacy Hospital EHR
Map the legacy EHR's HL7 v2 message schema (ADT, ORM, ORU segments) to the new platform's domain (Patient, Encounter, Order, Result). Identify the 6-10 anti-patterns in the lega…
- Anti Corruption Layer
- Hl7 Integration
- Domain Modeling
Domain-Driven Design
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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