L-01Difficulty: easyeasy
LRU Eviction Debug
Core Algorithms
- clear bar
- ~2200 tokens / 3 prompts
- Go
- ~20 min
Index · 20 challenges / 4 stages
The catalog.
Twenty challenges, four stages. No account needed to start.
Showing 20 / 20 levels
Stage 1 — The Bootsector
easyWarm up on real, gnarly-but-small problems — mostly fix a bug or fill one function — and learn the Promptly optimization loop in under 25 minutes.
L-02Difficulty: easyeasy
Bounded Ring Buffer
Data Pipelines
- clear bar
- ~2600 tokens / 3 prompts
- Go
- ~25 min
L-03Difficulty: easyeasy
Sliding-Window Rate Limiter
Web Systems
- clear bar
- ~2400 tokens / 3 prompts
- TypeScript
- ~25 min
L-04Difficulty: easyeasy
Crawler Race Fix
Concurrency
- clear bar
- ~2400 tokens / 3 prompts
- Rust
- ~25 min
L-05Difficulty: easyeasy
ORM N+1 Fix
Database
- clear bar
- ~2000 tokens / 2 prompts
- Python
- ~20 min
Stage 2 — Distributed Chaos
medium2/5 unlockedApply distributed-systems thinking by debugging or completing one slice of a protocol — not building Raft or SWIM end to end.
2 of 5 unlocked · clear more in The Bootsector to open the rest.
L-06Difficulty: mediummedium
Leader Election Debug
Distributed
- clear bar
- ~3800 tokens / 3 prompts
- Python
- ~30 min
L-07Difficulty: mediummedium
Vector Clock
Distributed
- clear bar
- ~3400 tokens / 4 prompts
- Go
- ~25 min
L-08Locked
CRDT Convergence Debug
Real-time
L-09Locked
Worker Pool Deadlock
Systems
L-10Locked
Goroutine / Conn Leak
Resource Leaks
Stage 3 — The Black Hat
hard2/5 unlockedSecurity and correctness work where AI helps you verify, patch, or pinpoint — provided primitives mean no implementing crypto from zero.
2 of 5 unlocked · clear more in Distributed Chaos to open the rest.
L-11Difficulty: hardhard
AEAD Timing-Leak Debug
Cryptography
- clear bar
- ~4200 tokens / 3 prompts
- Rust
- ~30 min
L-12Difficulty: hardhard
Constant-Product AMM
DeFi logic
- clear bar
- ~4400 tokens / 4 prompts
- TypeScript
- ~30 min
L-13Locked
Schnorr + Merkle Verify
Auth / ZK
L-14Locked
SQLi + Proto Pollution
AppSec
L-15Locked
Obfuscated Loop Debug
Reverse Eng.
Stage 4 — Quantum & Scale
expert2/5 unlockedPrestige capstones (30–45 min) — scaffolded single-module implementations or deep debugging, still CPU-gradable.
2 of 5 unlocked · clear more in The Black Hat to open the rest.
L-16Difficulty: expertexpert
Online-Softmax Block
AI Systems
- clear bar
- ~6000 tokens / 5 prompts
- C++
- ~45 min
L-17Difficulty: expertexpert
Bytecode Constant-Fold
Compilers
- clear bar
- ~5600 tokens / 4 prompts
- Python
- ~35 min
L-18Locked
Sweep-and-Prune Collision
Game Dev
L-19Locked
NumPy Training NaN
ML Ops
L-20Locked
Scheduler Deadlock
Systems