Practice the engineering
skills AI can't replace.
A gym for software engineers. Solve real production incidents, debug actual code, review pull requests, and write postmortems — then get AI coaching on your reasoning.
Structured Language Practice Zero to Hero
Step-by-step curated problem series to take you from foundational syntax to advanced data structures and dynamic programming.
Java Zero to Hero
150 curated Java problems covering Basic Programming, Arrays, Strings, Trees, DP & System Design.
Python Zero to Hero
150 Python practice problems focused on clean code, list comprehensions, OOP & algorithms.
C++ Zero to Hero
High-speed competitive programming & memory management track with STL algorithms.
JavaScript & TS
Fullstack JS & TypeScript track: event loop, async/await, closures & algorithms.
Hack With Infy
14 official Infosys competitive programming questions.
CHALLENGE TYPES
More than just coding exercises.
Real engineering requires debugging, communication, code review, and architectural thinking. We practice all of it.
Debug & Fix
Real production bugs. Find the root cause, fix it, explain why it broke.
Root Cause Analysis
Given logs and metrics, identify what went wrong — no coding required.
Code Review
Read a PR. Find the bugs, security issues, and code quality problems.
Communication
Write incident postmortems, explain bugs to PMs, draft release notes.
AI Collaboration
Use AI as your partner. We evaluate whether you verify and improve its output.
Architecture
Improve a system's scalability, reliability, security, or performance.
LEARNING FLOW
Every challenge follows a deliberate practice loop.
01
Read the scenario
A real production context — not a toy example.
02
Explore the evidence
Logs, code, metrics — whatever the incident provides.
03
Solve the problem
Fix code, write analysis, or both depending on the type.
04
Explain your reasoning
The how matters as much as the what.
05
Receive feedback & reflect
AI coaching + a moment to note what you learned.
AI COLLABORATION
AI is your learning partner,
not something to penalize.
Every workspace includes a built-in AI assistant. Use it freely — ask questions, explore ideas, get unstuck. We never penalize you for it.
We do evaluate whether you understood, verified, and improved what the AI gave you. That's the skill that matters.
AI ASSISTANT
YOUR SKILLS
SKILL RADAR
See exactly where
you're improving.
Track 7 independent engineering skills. See your strengths clearly. Know exactly what to practice next.
Am I becoming a better engineer?
Proofstack answers that.
Deliberate practice. Real engineering scenarios. AI coaching. One challenge a day builds real skills.
Start your first challenge