Introducing drillcode: coding interview prep that builds muscle memory
560+ free drills across 22 categories. No accounts, no paywalls, no fluff.
Most interview prep feels like reading a textbook. You understand the concept, nod along to the solution, and then freeze when you see it on a whiteboard.
The gap isn't knowledge — it's recall speed. You know what a monotonic stack is, but can you write it in 30 seconds under pressure?
drillcode closes that gap with repetition. Short drills you type from memory until the patterns stick.
What's on the site
249 Micro Drills — the core of the site. Each one is a single code snippet: swap two elements, BFS template, sliding window, trie insert. You see the title, recall the code, type it. Target time: 5–15 seconds. No problem-solving, no reading — just raw pattern recall.
150 Pattern Recognition Drills — given a problem description, identify the pattern before looking at the solution. Trains the "which algorithm do I use?" skill that separates quick solvers from slow ones.
15 Decision Frameworks — the newest section. Decision trees for algorithm selection: BFS vs DFS, backtracking vs DP, stack vs queue, fixed vs variable window. When you're staring at a problem and don't know where to start, these frameworks give you the first move.
Foundations — one essential drill per topic. If you're short on time, start here. Each foundation links to related micro drills so you can go deeper.
How to use it
The site is designed for daily reps, not marathon sessions.
Morning warm-up (5 min): Hit "Random Micro" a few times. Type each snippet from memory. If you can't, read it once and try again.
Focused practice (15 min): Pick a weak category. Work through the micro drills in order. Then do 2–3 coding drills from the same topic.
Pattern training (10 min): Do 5 pattern recognition drills. Read the problem, guess the pattern, check the answer. Speed matters here.
The goal is to make common patterns automatic. When you see "shortest path in unweighted graph" your fingers should reach for BFS without thinking.
Email subscriptions
Don't want to remember to visit? Subscribe and get drills in your inbox. Pick your drill type (micro, patterns, or foundations), set your frequency (every 20 minutes to every 4 hours), and choose your active hours.
What's next
The site is in beta and I'm actively adding content. Coming soon:
More frameworks for advanced topics (segment trees, union-find strategies, advanced DP patterns)
Spaced repetition tracking — surface drills you've struggled with more often
Difficulty progression within each category
Everything is free. No sign-up required to browse. The subscription is optional and also free.
Try it: drillcode.xyz