This guide tracks 10 patterns (2 of them typically hard), 14 commonly reported questions, and a 5-round loop that usually runs 4-8 weeks.
Key patterns
Showing 3 of 10Common questions
Showing 3 of 14Interview process
Showing 1 of 5 roundsStart studying now, without an account
Every lesson below is a free public reading page. No sign-up, no install, and the worked examples run in the tab.
The Python behind Google's top patterns
These lessons do not teach the patterns themselves. They teach the language mechanics each pattern is built from, which is the part you have to have in your hands before the pattern is worth practicing.
- Arrays & HashingPython10 min readTuples & setsGroup fixed records with tuples and track uniqueness with sets.
- Arrays & HashingPython10 min readDictionariesMap keys to values: read safely, assign, and merge dictionaries.
- Binary SearchPython22 min readShrink the failing inputA bug report with a 400 row file is not a diagnosis. Cut the input down until removing anything else makes the failure disappear, and the answer is usually visible.
- TreesPython11 min readRecursion: a function that calls itselfSolve a problem in terms of a smaller version of itself, with a base case to stop.
- BFS (Breadth-First Search)Python12 min readCounter, defaultdict & dequeReach for specialized collections: count with Counter, group with defaultdict, queue with deque.
- Dynamic Programming (1D)Python20 min readProfiling, complexity & cachingFind the hot path, fix complexity, and memoize repeated work with lru_cache.
Google runs a system design round
The System Design course opens with the method itself: how to scope a vague prompt, turn it into requirements you can defend, and budget the clock. You write your own answer first, then reveal a model answer to compare against.
- System design roundSystem Design25 min readClarifying a Vague PromptTurn a one-line prompt into a scoped problem with three to five sharp questions and explicit out-of-scope.
- System design roundSystem Design20 min readFunctional RequirementsPick the three user capabilities that define the core loop, phrase them as 'users can X', and defer the rest with a reason.
- System design roundSystem Design25 min readNon-Functional Requirements, QuantifiedTurn 'scalable and reliable' into quantified, testable targets (p99, nines, QPS) and name the design lever each one forces.
How Google judges you outside the code
The values and engineering norms the interviewers are calibrated against. Useful for the behavioral round, and useful for deciding which trade-off to argue for in the technical one.
Values they name
- Focus on the user and all else will follow
- Democracy on the web works
- You can make money without doing evil
- Great just isn't good enough - 10x thinking
- You can be serious without a suit
- Fast is better than slow
What they look for in behavioral rounds
- Demonstrate Googliness: humble, collaborative, intellectually curious
- Show you can navigate ambiguity and make data-driven decisions
- Exhibit leadership without authority - influence through expertise
- Display comfort with technical depth and breadth
- Show passion for technology and solving complex problems
How the team builds
- Design docs are required for significant changes
- Code reviews are thorough and educational
- Testing is a first-class citizen - high coverage expected
- Prefer simple solutions over clever ones
- Readability and maintainability over brevity
Primary stack
- C++
- Java
- Python
- Go
- JavaScript/TypeScript
- Borg/Kubernetes
- Spanner
- BigTable
- Code review
- thorough async reviews with readability focus
- Deployment
- continuous deployment with canary releases
- Documentation
- design docs required for significant changes
Reading the guide is the easy part. Google will ask you to perform.
CodeSparring is a practice environment, not a question bank. You sit a full round against an AI interviewer, in an editor that runs your code, and you leave with a score and a specific next rep.
An interviewer that reacts
Carry one problem from clarifying questions through to working code while an AI interviewer responds to what you say and what you type, by voice or by text.
Code that actually runs
An editor in the page with a real runtime and real test cases. You run your solution and read the output, the same way you would in a shared editor on the day.
A scored round, not a vibe
Every session ends with a rubric covering problem solving, communication, and code quality, so you can see which part of the round is costing you the offer.
And 364 lessons you can read right now, free
The whole curriculum is public. Read the concept, run the worked example in the tab, and only sign in when you want the graded exercise at the end of a lesson.