Developer interview preparation advice tends to assume one particular process — the multi-round algorithmic gauntlet used by a handful of very large technology companies. Most developer jobs do not interview that way, and preparing as though they do wastes weeks.
The first useful step is working out which process you are actually facing.
Find out the format before you prepare
It is entirely normal to ask a recruiter what the interview stages are. Most will tell you. What you want to know is how many rounds there are, whether there is a take-home or a live coding exercise, and whether the technical round is algorithmic or practical.
That single question changes what you should spend your preparation time on more than anything else in this article.
The four things being tested
Across almost every format, developer interviews are assessing four things:
Can you write working code. Not perfect code, and rarely optimal code. Working code, in front of someone, without freezing.
Can you explain your reasoning. Interviewers care more about how you approach an unfamiliar problem than whether you land on the ideal answer. Silence is the failure mode; a wrong approach explained clearly is often a pass.
Do you understand what you have previously built. Anything on your CV is fair game. If you cannot explain a technical decision in your own project, that is worse than not having the project.
Would working with you be straightforward. Almost every process has a round that is really about this, whatever it is called.
Preparing for a practical or take-home exercise
This is the most common format outside big tech. Usually you are asked to build something small, or to extend an existing codebase.
Treat it as a work sample, because it is one. That means a README explaining your decisions and trade-offs, tests if the brief mentions testing at all, clear commit history, and — importantly — finishing within the stated time rather than gold-plating for three days. Reviewers notice when a "four hour exercise" clearly took twenty, and it does not read as enthusiasm.
If you had to leave something out, say so in the README and explain what you would do with more time. That is a stronger signal than pretending the omission was deliberate.
Preparing for an algorithmic round
If the process genuinely includes one, the highest-value preparation is narrow: arrays and strings, hash maps, two pointers, basic recursion, and one sorting and one searching approach you can implement from memory. Being able to talk about time and space complexity in ordinary language matters more than memorising which exotic structure solves which puzzle.
Practise saying your reasoning out loud while you code. It feels unnatural and it is the specific skill the round tests.
Preparing to discuss your own work
Pick two projects. For each, be able to answer: what problem did it solve, why did you choose that approach, what broke, and what would you do differently. Write the answers down once; you will not need the notes again.
The "what broke" answer is the one that distinguishes candidates. Everyone's project worked in the demo. Being able to describe a real failure and what you learned from it is far more convincing than a flawless narrative.
Questions worth asking them
Ask what the first three months look like for this role. Ask how code gets reviewed and released. Ask what the team is finding difficult right now.
These are not scoring points — they are how you find out whether the job is any good. A vague answer to "how does code get to production" tells you something real.
The evening before
Do not learn anything new. Re-read the job description, re-read your own CV, check the interview link and timezone, and stop. Preparation done the night before mostly buys anxiety.
A realistic expectation
Interview processes are noisy. Strong candidates get rejected for reasons that have nothing to do with them — an internal candidate, a changed budget, a bad interviewer. Preparation improves your odds substantially; it does not make any single outcome certain. Judge your process by how you performed, not by whether one particular company said yes.