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Prep Plan
How to prepare, what to prioritise, and a week-by-week roadmap.
Last reviewed 2 Sept 2026
A full-stack interview loop usually has four kinds of round: coding / DSA, system design, a deep-dive on your own work, and behavioral. Bigger companies weight DSA and system design heavily; smaller teams weight practical coding and your project history. This plan gets all four warm at once.
The one rule for talking about your own work
Never claim a decision you cannot defend. For every non-trivial choice in a project — a database, a framework, an auth model, a caching layer — be ready to say why it was the right call and what the alternatives cost. “It was generated / it was already there and I kept it” is fine only if you can then justify keeping it. Interviewers find the gap between a senior-sounding resume and shallow ownership with three follow-ups: why that way?, what broke?, what would you change?
What each round is really testing
| Round | What they score | How to prepare |
|---|---|---|
| Coding / DSA | Can you pattern-match a problem, code it cleanly, reason about complexity, and communicate while doing it | Volume + a fixed problem-solving script (see the DSA track) |
| System design | Can you take a vague prompt to a working architecture, make trade-offs explicit, and handle scale and failure | A repeatable framework + building blocks + worked problems (see the System Design track) |
| Project deep-dive | Do you actually understand what you built, or only describe it | Re-open the repo, trace one request end to end, redraw the schema from memory |
| Behavioral | Ownership, conflict, judgement, communication — with real examples | 7–8 rehearsed STAR stories (see the Behavioral track) |
A four-week schedule
Assumes roughly 2–3 focused hours on weekdays and more on weekends. Compress to two weeks by doubling the daily load; stretch to eight by halving it. Start applying at the end of week two so real interviews land in weeks three and four — early ones are calibration.
Week 1 — DSA engine on, re-own your systems
- DSA every day: arrays and hashing, two pointers, sliding window, stack. Start a “pattern → trigger” log.
- Clone and run every project you will talk about. For the two or three you will lean on: trace one full request end to end, then redraw the schema and architecture from memory and check.
- Fill a “must be able to explain” list for each project — write the answers out loud.
- Behavioral: draft one STAR story per day.
Week 2 — Finish deep-dives, fundamentals, start applying
- DSA: binary search, linked lists, trees (traversal, BFS, BST). Re-solve week-1 misses.
- Fundamentals pass: the language runtime, HTTP and idempotency, auth and token handling, SQL indexing and isolation levels, caching and cache invalidation.
- Finish the STAR set (7–8 stories); draft “why leaving”, “why this company”, and your questions for them.
- Start applying. Referrals first.
Week 3 — System design and behavioral, first mocks
- DSA: heaps, backtracking, graphs (BFS/DFS, grid problems, topological sort). First timed mock interview.
- Learn the system-design framework and building blocks. Two timed 45-minute mock designs; record yourself and note every hand-wave.
- Rehearse four STAR stories aloud with follow-ups; do one full behavioral mock.
Week 4 — Integrate and run real loops
- DSA: intervals, greedy, light dynamic programming. Then re-drill every problem you missed all month.
- Two full mock loops (coding + system design + behavioral). Debrief hard.
- Real interviews start landing. Before each: a 20-minute DSA warm-up and a re-read of that company’s notes.
Beyond week 4 — sustain
Maintenance mode: one medium problem, one spoken design prompt, and two STAR stories re-read, daily. After every real interview, write down each question you fumbled and fix it that night. Keep several processes alive to the offer stage — it is your only real negotiating leverage.
Interview-day checklist
- 20–30 minute DSA warm-up so you are not cold on the first problem.
- Re-read your one-pager on the company and your questions for them.
- Have ready in one sentence each: your current role and dates, why you are leaving, your years of experience.
- Coding: clarify, examples, brute force with its complexity, optimise, code, test edge cases — narrating throughout.
- Design: run the framework out loud; state trade-offs unprompted.
- Behavioral: STAR, lead with the result, keep each story under about two and a half minutes, then stop.
- If you do not know something, say so and reason toward an answer aloud. That scores better than bluffing.