About Sweaty Imposter
A free, local-only interview prep app for junior, mid, and senior engineers. Pattern recognition, system design, Big O, behavioral, and timed mock loops — everything runs in your browser.
Most interview prep assumes the problem is that you cannot solve things. Usually it is not. You solved these before — you just have not looked at a monotonic stack in eight months, and the thing that fails you at 1 AM is recall, not intelligence. So this app drills recognition and recall in short reps: name the pattern, name the complexity, pick the building block, defend the tradeoff. The kind of practice that fits in the fifteen minutes you actually have.
It also covers the rounds that quietly decide loops and that almost nobody rehearses — behavioral, code review, SQL, security, API and database design — because a strong coding round rarely saves a weak everything-else.
Built by Disco Volante Labs as a personal side project.
What's inside
Coding rounds
Recognize the pattern before you write anything, then implement it. Pattern Triage, Solve, Write, Complexity, Algorithms, and Big O.
System design rounds
Four angles on the same skill — assemble the architecture, go deep on one system, survive escalating scale, or read the canonical write-up.
The rounds people skip
Behavioral is 30-50% of most loops, and senior loops lean hard on code review, SQL, security, and API design.
Reference and planning
Read up before you drill, follow a curriculum sized for your level, or run a timed mixed-mode session under real pressure.
Common questions
Is Sweaty Imposter free?
Yes — everything is free. There is no paywall, no subscription, and no premium tier. Every practice mode and every page of the reference library is open to everyone.
Do I need an account?
No. Your streak, accuracy, and review history are written to your own browser's local storage, which means they stay on the device you practiced on and disappear if you clear site data.
How is this different from LeetCode?
LeetCode is a bank of problems to solve end to end. Sweaty Imposter drills the things around that: recognizing which pattern a problem wants before you start coding, recalling complexity cold, and rehearsing the system design, code review, SQL, security, and behavioral rounds that decide most loops.
What should I practice first?
Start with Pattern Triage — you see a problem and name the pattern, no coding. It is the fastest way to find the gaps. If you would rather follow a plan, pick the study track that matches the level you are interviewing at.
Does it cover system design interviews?
Yes, four ways: pick the building blocks for a classic prompt, work one system facet by facet in the deep dive, handle escalating scale in evolving scenarios, or read the canonical write-ups in the library.
Which programming languages are supported?
Write mode accepts Java and Python, and shows the canonical solution in both so you can compare against your own implementation.
How long does interview prep take?
The study tracks are sized by level: roughly 25 hours for the junior track, 60 for mid-level, and 120 for senior. Spreading that across several weeks beats cramming, since most of what is being trained here is recall.
Does it work on a phone?
Yes. Every mode except Write is built for one-handed practice on a phone, and the site installs as a home-screen app. Write mode is available on mobile but genuinely easier on a real keyboard.
Other apps from Disco Volante Labs
Privacy
All your study progress lives in your own browser's localStorage. Anonymous usage analytics (page views, mode rates, session timezone) are collected via Firebase Analytics to understand what's useful — no personal data.