How to walk an interviewer through your GitHub project

This guide is published by Techtonic Innovations LLC, the company behind Co-Help. The walkthrough advice works with or without any tool; the Co-Help section near the end explains one way to rehearse it.

What the interviewer is actually testing

In a project walkthrough round, the interviewer opens your repository (or asks you to share your screen) and says some version of "walk me through this." There is no algorithm puzzle. What they are listening for is more personal:

• Decision-making. Can you explain why you chose this database, this framework, this folder structure, and what you gave up?
• Ownership. Which parts did you build yourself, and how deep does your understanding go when they ask a third "why"?
• Debugging judgment. Can you tell a real story about something that broke and how you found the cause?
• Self-awareness. Do you know the weak spots, and what you would do differently now?
• Fluency in your own code. Can you find the file you are talking about without searching for it?

Size and polish matter far less than people expect. A small project you can defend several levels deep beats an impressive one you half remember. F1Jobs' guide to this round makes the same point: choose the repository where you can justify your choices and name a real bug you fixed.

Pick the right project

• Choose the repo where you wrote the hardest parts yourself.
• Prefer a project with real decisions (a data model you redesigned, a queue you added, a cache you removed) over a long feature list.
• If it came from a class, bootcamp, internship or team, say so up front and be precise about your contribution. Overstating solo ownership is one of the fastest ways to lose trust in this round.
• If the deployed demo is broken or out of date, either fix it or do not show it.

A five-part walkthrough structure

Use this as the spine of your opener. Each part is one or two short paragraphs when spoken, which lands you at roughly three to five minutes in total.

1. The problem (about 30 seconds). Who it is for and what was painful before. "I built this because…" is a fine first sentence. Avoid reading the README aloud.
2. The architecture (about a minute). The main pieces and how a request or a piece of data moves through them. Name the two or three folders that matter, so the interviewer can follow along in the repo.
3. One key decision and its trade-off (about a minute). Pick the choice you can defend best: why this storage, this sync model, this library. Say what you rejected and why. "I chose X over Y because Z, and the cost was W" is the sentence interviewers want to hear.
4. The hardest bug (about a minute). Symptom, how you narrowed it down, the actual cause, the fix, and what you added so it would not come back (a test, a log line, a guard).
5. What you would change now (30 seconds). One or two specific things: a missing test suite, a schema you would split, a dependency you would drop. This shows growth, not weakness.

Example opener (illustrative)

That is around 150 words, under a minute and a half spoken. Expand each part only as far as the interviewer's questions take you.

Handling the follow-up questions

• "Why did you use X?" Give the reason you had at the time, even if it was "I knew it already." Then say what you would weigh today. Defensiveness reads worse than a simple reason.
• "How would this scale?" Name the first thing that would break and how you would notice. Do not claim it is already ready for millions of users.
• "How did you test it?" If there are no tests, say so and explain what you would test first and why.
• "Can you change this live?" Talk through the plan before you type. Interviewers care about your approach more than speed.
• "Who wrote this part?" Be exact. "My teammate built the auth; I integrated it and fixed the token refresh bug" is a strong answer.

Prep checklist for the week before

• Reread the code, especially entry points and the files behind your key decision and hardest bug.
• Check that the project still builds and any demo still works.
• Make sure the README and repository description are accurate.
• List each major dependency and the alternative you rejected.
• Write a one-paragraph summary and time yourself saying it out loud.
• Explain your hardest bug to someone without context, and notice where they get lost.
• Do a screen-share run-through, opening files without using search.
• Ask a friend to interrupt you with "why?" and "what if?" questions.

Rehearse it against your real code with Co-Help

The hard part of rehearsing alone is checking yourself: when you say "the retry logic lives in the worker," is that still true? Co-Help's GitHub-connected mode is built for exactly this kind of question, and you can use it as a rehearsal tool before the interview.

1. Connect GitHub. In the setup wizard, connect GitHub by pasting a GitHub personal access token. Co-Help can then read the repositories that token can access, including private ones if you grant it that permission. The token is stored encrypted on your device.
2. Add the project. Paste the repository URL. Co-Help reads the README, the real file structure and key files such as package manifests and entry points.
3. Run a rehearsal session. Ask a friend to play the interviewer on a call, or ask the questions yourself. For questions about the code, Co-Help searches your repositories and grounds its suggested answer in the matching source excerpts, each with a location in the form Project > folder > file > line you can open. Broad questions such as "walk me through the project" are answered from the README and the actual file list.
4. Check your explanation against it. Compare what you said with the cited code. When Co-Help says it would need to open a file to be exact, rather than guessing, treat that as a gap to close before the interview.

Two honest limits. Retrieval is keyword-based, so it can miss the right file or attach code that is not relevant; behavioral questions are answered without the code. And access to a repository is not proof of authorship: Co-Help explains what the code does and does not claim you wrote it, so the "who built what" answer still has to come from you.

To rehearse delivery as well as content, use practice mode with the coding or system design type and the job description pasted in. Each answer is scored on criteria such as "communication of approach" or "scalability and trade-offs", with a model answer. Practice mode writes its own questions from the role and job description; it does not read your repository.

Before you run a session: Some places require every participant's consent before a call is transcribed. You're responsible for getting it. The same GitHub grounding also works during live interviews. You're responsible for following the rules of your employer, school, interviewer and any platform you use. Many allow AI tools; some don't, so check first. AI answers can be wrong or incomplete. Review every suggestion before you rely on it.

More on how this fits technical rounds: coding interview assistant and system design interview assistant. For spoken practice in general, see AI mock interview practice.

Frequently asked questions