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Curated practice for the Google SWE interview loop, calibrated to L4 expectations.
Google's L4 SWE loop is built around two coding rounds, a system design round, and a Googleyness/leadership round. Coding rounds emphasize algorithmic clarity, edge-case handling, and clean code over raw speed. System design enters the loop at L4, but expectations are bounded - you should be fluent in fundamentals (caching, sharding, load balancing, queues) without needing to design a full Spanner-scale system. The Googleyness round is not a soft round - structured behavioral questions probe collaboration, ambiguity, and your motivation for working at Google. This pack groups practice questions by the topics actually tested at L4, with framing on what each round is looking for.
Two of three coding rounds focus here. Expect Medium difficulty with optimization follow-ups - 'can you do this in better space?'
Trees, graphs, hash tables, heaps. Tries appear more often than you would expect for autocomplete-style problems.
Required at L4 but bounded. Don't try to design Spanner. Pick a sensible scale, walk through the components, defend trade-offs.
The Googleyness round is structured. Prepare 6-8 STAR stories covering conflict, ambiguity, leadership, learning, impact.
Comes up inside system design - sharding, indexing, ACID vs BASE. Rare as a standalone topic.
Used in a coding round if you get a design-y problem (parking lot, elevator). Less common at L4 than at L3.
Curated walkthroughs for the bounded designs that show up in Google's system design rounds. Capacity estimation, architecture, deep-dives, and trade-offs.
The canonical bounded system design problem. Read-heavy, hot-key prone, and a great vehicle for hashing, caching, and capacity estimation.
The classic write-vs-read amplification trade-off. Push, pull, or hybrid fanout - and how to handle the celebrity user with 100M followers.
Long-lived connections, ordering guarantees, presence, and the difference between 1:1 chat and a 50K-member group.
Five algorithms, three sharding strategies, one fail-open vs fail-closed decision. The bounded design that surfaces in every backend interview loop.
Encoding ladders, adaptive bitrate, CDN economics, and the difference between live and VOD. Petabyte-scale storage meets millisecond-scale playback.
Geo-indexing, real-time matching, ETA prediction, and surge. The canonical geo-spatial design problem with hard real-time constraints.
Politeness, deduplication, freshness, and the URL frontier. The classic crawl-the-internet question that surfaces deep distributed systems judgment.
Sample STAR answers, common prompts, pitfalls, and follow-up strategies for the behavioral themes that decide Google's loop.
Not a soft round. Structured questions about collaboration, ambiguity, learning, and motivation - scored against rubrics, not vibes.
Tested at Google, Anthropic, OpenAI, and any senior+ loop. Strong candidates show how they get curious; weak candidates show how they get anxious.
The most universal behavioral question. Tested everywhere. The signal is in how you investigate the disagreement, not in how you 'won.'
Microsoft's Growth Mindset core. Also tested at Google, Anthropic, and any company that screens for self-awareness. The signal is whether you actually changed.
Total comp ranges, base, equity, and bonus across the levels tested in this loop. Aggregated from public sources.
5 SWE levels covered. Updated 2026-05.
357 MCQs and 237 coding challenges, grouped by topic. Free preview shows question titles - premium unlocks full content.
Behavioral and system design rounds reward practice with a live AI interviewer that probes follow-ups, not silent reading.
Start an AI mock interview →L3 is entry-level (new grad). L4 is mid-level with 3-5 years of experience. The bar at L4 includes system design as a required round, deeper behavioral signal, and an expectation that coding rounds will surface follow-up questions to test depth. L3 candidates often skip system design or get a much lighter version.
Yes, but less than the meme suggests. Coding rounds use LeetCode-style problems as a vehicle for evaluating problem solving, code clarity, and communication. Memorizing 300 problems will not help if you can't articulate your approach. Practice talking through problems out loud.
Enough to drive a 45-minute design of a moderately complex system (chat app, news feed, URL shortener) without freezing. You should know caching layers, load balancing, database sharding, eventual vs strong consistency, and message queues. You don't need staff-level depth on consensus protocols or custom storage engines.
Three things: do you collaborate well, do you handle ambiguity, and do you actually want to work at Google. It's structured - questions are scored against rubrics, not vibes. Vague stories or 'I'm a hard worker' answers score poorly. Prepare specific incidents using STAR.
Recruiter screen to onsite typically takes 4-8 weeks. After the onsite, hiring committee review takes 1-3 weeks, then team matching can take another 2-6 weeks. Plan for 2-4 months end to end. Use that time to keep practicing - most candidates lose momentum between rounds.
Yes. Standard cooldown is 6-12 months depending on how close you were. Recruiters track which round was the weak signal and will sometimes coach you on what to focus on. Many engineers get hired on attempt two or three.