Code Challenges

Build a working backend, frontend, integration, or data pipeline against a real-shaped spec.

DisciplineAll Analysis Code Design Strategy Research Presentation

LevelAll Foundational Beginner Intermediate Senior

SkillsBrowse skill families

CodeFoundationalNew
Replace a Naive List with a Heap in a Delivery Dispatcher
Read the current dispatcher source (around 400 lines of Python). Identify the linear scan and the operations that touch it (insert, decrease-key on a re-scored courier, extract-…
- Heap Data Structure
- Complexity Analysis
- Python Or Javascript
Data Structures
CodeSeniorNew
Build a Lock-Free MPMC Queue for a Trading-Backend Hot Path
Implement Vyukov's bounded MPMC queue in C++20 using atomic operations with explicit memory orderings (relaxed where safe, acquire/release on the enqueue/dequeue handshake). Use…
- Lock Free Algorithms
- Memory Models
- Systems Language Proficiency (Go, Rust, C++)
Advanced Concurrency and Parallel Computing
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
CodeBeginnerNew
Build a Wake-Word Detector for a Smart-Speaker Startup
You receive a small public Japanese-speech dataset, 30 hours of recorded wake-phrase utterances from 50 volunteers, and 200 hours of background-noise recordings. Train a lightwe…
- Keyword Spotting
- Speech Recognition
- On Device Ml
Speech Recognition and Spoken Language Processing
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
CodeSeniorNew
Reverse-Engineer and Patch an N-Day Vulnerability in a Vendor Binary
Receive the vulnerable binary (Linux ELF, x86-64), the public CVE-2025-XXXX advisory + PoC, and the bank's deployment context (RHEL 9, the binary runs as a non-root service). Lo…
- Reverse Engineering
- Binary Exploitation
- Ghidra
Computer Systems Security
CodeBeginnerNew
Shortest-Path Routing for a Bike-Share Operator
Receive the graph (nodes with lat/lon/elevation, edges with length and slope) and 50 origin-destination test pairs. Implement Dijkstra's algorithm with a custom edge-weight func…
- Graph Algorithms
- Dijkstra
- Algorithm Analysis
Algorithm Design and Analysis
CodeIntermediateNew
Build a Multilingual Customer-Email Classifier
You receive 28,000 labeled emails (skewed toward English and Mandarin). Try at least two approaches: (1) a fine-tuned multilingual transformer (XLM-RoBERTa or mDeBERTa) and (2) …
- Text Classification
- Multilingual NLP
- Hugging Face Transformers
Natural Language Processing
CodeBeginnerNew
Quantize a Vision Model for a Smart-Doorbell SoC
You receive a trained FP32 PyTorch person-detector (mAP 0.74 on a 5k validation set) plus a calibration dataset of 500 unlabeled doorbell frames. Convert to ONNX, then apply pos…
- Quantization
- Model Optimization
- Onnx Optimization
Edge ML and On-Device Machine Learning
Explore role
Marketing Analyst
Plan and measure campaigns that grow the business. Funnel analytics, attribution, segmentation, and the rigorous measurement that lets marketing defend its budget at the leadership table.
Browse challenges
CodeBeginnerNew
Reduce Dimensionality on Sensor Streams for a Mid-Cap Robotics OEM
You receive 120 robot-hours of windowed sensor data (5s windows, 240 channels) with labels for normal vs. one of four fault classes. Implement (1) PCA, (2) kernel PCA with an RB…
- Dimensionality Reduction
- Kernel Methods
- Autoencoders
Machine Learning
CodeIntermediateNew
Build an Audio-Visual Speaker Diarization Pipeline
Build the pipeline: face detection + active-speaker detection on video, voice-activity detection + speaker embeddings on audio, then a fusion step that ties tracks to detected f…
- Audio Visual Fusion
- Speaker Diarization
- Active Speaker Detection
Multimodal Machine Learning
CodeBeginnerNew
Convert an Imperative Recommendation Service to Pure Functional Style
Take the Python ranking module (around 900 lines). Identify side-effects (DB reads, cache lookups, logging, time) and lift them to the boundary. Rewrite the ranking core in Scal…
- Scala Programming
- Pure Functions
- Functional Core Imperative Shell
Functional Programming
CodeBeginnerNew
Bootstrap a Production-Grade CI/CD Pipeline for a Pre-Seed Startup
Audit the current deploy process and document the 6-point checklist of risk it removes. Build the pipeline in GitHub Actions: (1) PR check workflow, (2) main-branch build with m…
- Ci Cd
- Github Actions
- Container Signing
DevOps and Secure Deployment
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
CodeSeniorNew
HyperLogLog Cardinality for Real-Time Ad-Auction Analytics
Implement HyperLogLog with precision parameter p in {12, 14, 16} (4KB, 16KB, 64KB sketches) and benchmark relative error on a replayed 3-hour production trace (around 13 billion…
- Hyperloglog
- Probabilistic Data Structures
- Streaming Systems
Randomized Algorithms
CodeIntermediateNew
Distributional Embeddings for a Multilingual Legal Search
Use a public multilingual corpus (e.g., MultiEURLEX or a subset of EUR-Lex) plus a small hand-built test set of around 100 cross-lingual query-passage pairs. Fine-tune (or evalu…
- Distributional Semantics
- Multilingual NLP
- Sentence Embeddings
Computational Semantics
CodeIntermediateNew
Migrate Stateful Workloads to StatefulSets with Storage Class Tuning
Receive the current Redis Sentinel topology (3 nodes, ~120GB data), the EBS gp3 baseline performance requirements (3,000 IOPS, 125 MB/s), and the cluster (EKS 1.29 with the EBS …
- Kubernetes Orchestration
- Statefulsets
- Storage Classes
Container Orchestration with Kubernetes
CodeIntermediateNew
Build a Tool-Calling Agent for an Internal Reporting Bot
You will implement the agent in either LangChain or LlamaIndex (your choice; defend it in the readme). Wire 4 tools: (1) read-only SQL on a sample warehouse, (2) a mocked BI met…
- Agent Orchestration
- Tool Calling
- Langchain Or Llamaindex
LLM Application Development
CodeIntermediateNew
Train a Domain-Specific Reranker for a Legal-Tech Search Box
You receive 20,000 (query, document, relevance-label) triples from the firm's contract corpus. Fine-tune a small cross-encoder (e.g., ms-marco-MiniLM-L-6-v2 or BAAI/bge-reranker…
- Cross Encoder Reranker
- Fine Tuning
- Ir Evaluation
Information Retrieval and Search
CodeIntermediateNew
Build an Evaluation Harness for an Internal LLM Assistant
You will design and implement an evaluation harness in Python that runs four test suites: (1) helpfulness (LLM-as-judge with rubric), (2) factual grounding (compare cited source…
- LLM Evaluation
- LLM As Judge
- Prompt Injection Testing
Large Language Models
CodeIntermediateNew
Restore Smartphone Low-Light Photos for a Consumer AI App
You receive 200 paired low-light / well-lit phone photos plus 1,000 unpaired low-light photos. Build a pipeline that combines a learned denoiser (e.g. a small DnCNN-style model …
- Image Restoration
- Denoising
- Tone Mapping
Image Processing and Computational Imaging
CodeIntermediateNew
Offline-First Mobile App for Field Service Technicians
Build a Flutter prototype against a mock API serving work orders, asset history, and a parts catalog. Implement: local-first storage with Drift (or Isar) for relational data and…
- Mobile Development
- Flutter
- Offline First Design
Mobile Application Development
CodeBeginnerNew
Build a Functional Image-Filter Pipeline for a Photography SaaS
Design a Filter as a function from (pixel matrix → pixel matrix). Build a compose helper that takes a list of filters and returns a single composed filter (function composition)…
- Higher Order Functions
- Function Composition
- Abstraction
Programming Abstractions
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
- Apache Spark
Data Engineering and Big Data Systems
CodeIntermediateNew
Implement Model Predictive Control for a Delivery Robot
You receive a kinematic bicycle model of the robot, a published track layout, and 30 minutes of recorded waypoint trajectories. Implement a nonlinear MPC controller using acados…
- Model Predictive Control
- Optimal Control
- Robotics Simulation
Advanced Robotics
CodeBeginnerNew
Add Constant Folding and Dead Code Elimination to a Toy Compiler
Fork the repo, read the IR specification (3-address code, register-based, documented in /docs/ir.md). Implement constant folding as an IR-to-IR pass: any operation on literal op…
- Intermediate Representation
- Constant Folding
- Dead Code Elimination
Compiler Construction

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Step 03
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Step 04
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Step 05
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Code Challenges | Ewance