# Coding interview prep, out loud

Canonical: https://duckyhelper.com/for/coding-interviews/
Updated: 2026-10-01

DuckyHelper helps you prep for coding interviews by tutoring you on the problem in your own editor or on LeetCode. Talk through your approach out loud, the way you would in an interview. Ducky gives hints one at a time, runs your code against test cases in a sandbox on your Mac, traces it step by step to show where it breaks, and can walk you through writing a solution chunk by chunk.

## One problem, start to finish

**Two Sum, with Ducky**

1. You open the problem and press **fn**: "I'll try a nested loop first. Is that OK?" Ducky asks you for the time complexity, and whether you can do better.
2. You're not sure. You open a hint: a nudge about remembering numbers you've already seen. Then a bigger hint about a dictionary.
3. You write the code. Ducky runs it against the examples and edge cases, LeetCode style. Each test ticks in; one fails and shows expected versus what you got.
4. You ask why. Ducky plays your code step by step on a card: the line running, the dictionary filling up, and the step where the index goes wrong.
5. You fix it and run the tests again. All pass. Ducky saves a flashcard about the pattern for later.

## The coding tools

| Tool | What it does |
| --- | --- |
| Run code | Runs your function or program against 3 to 8 tests in a sandbox on your Mac with no internet. Python, JavaScript and TypeScript. |
| Step-through visualizer | Plays your code step by step like Python Tutor: frames, variables, arrays with index pointers, dicts, linked lists and trees. |
| Code walkthrough | Ghosts the next small chunk of code at your caret in your own editor (LeetCode, VS Code, any text box). Type it and the next step follows. Say "let me try myself" to hide it. |
| Hint ladder | A nudge, a bigger hint, the worked step, and the answer last. You choose how far to go. |
| Whiteboard | Diagrams and sketches while you explain your approach, step by step. |

> **Note: These tools are in the Mac app**
>
> In a browser at [app.duckyhelper.com](https://app.duckyhelper.com), share your LeetCode tab and talk the problem through: Ducky reads it, marks up the preview, works steps and uses the whiteboard. Running your code, the visualizer and the code walkthrough need the Mac app.

## Practice the talking part

Interviewers want to hear how you think. With Ducky you already practice out loud: explain your plan before you code, and Ducky asks the follow-up questions an interviewer might, like the time and space cost or an edge case you skipped.

## What it won't do

- Don't use DuckyHelper during a real interview or a graded coding test unless you're allowed to. It's a study tool.
- It isn't a mock-interview service with real interviewers, and it has no list of any company's questions.
- Its code and explanations can be wrong. Running your code against tests is the check; trust what passes.

## Frequently asked questions

### Does DuckyHelper work with LeetCode?

Yes. Ducky sees your screen, so it can read a LeetCode problem and your code, run your solution against test cases in a sandbox on your Mac, and ghost code at your caret right in LeetCode's editor during a walkthrough.

### Which programming languages does DuckyHelper run?

Its code runner and step-through visualizer support Python, JavaScript and TypeScript. These run in the Mac app. Ducky can talk about code in other languages on your screen, but it runs only those three.

### Will Ducky just give me the solution?

Only if you ask for it. It starts with questions and a hint ladder, and in a code walkthrough you can hide the ghost text and write each step yourself. The aim is that you can solve the next one without it.

### Can I use DuckyHelper in a live interview?

No. Don't use it during a real interview or coding test unless you're allowed to. Use it to practice beforehand: talk through problems out loud, run your code against tests and review the patterns you missed.

## Related

- [Study from your own lectures, out loud](https://duckyhelper.com/for/college-students/)
- [DuckyHelper for Mac](https://duckyhelper.com/for/mac/)
- [Plans and pricing](https://duckyhelper.com/pricing/)
- [DuckyHelper features](https://duckyhelper.com/features/)
- [DuckyHelper compared](https://duckyhelper.com/compare/)

## Try asking Ducky

- "Give me a hint for this one, not the answer."
- "Run my solution against the examples and some edge cases."
- "Step through my code and show me where the index goes wrong."
- "Ask me the questions an interviewer would ask about this solution."

## Get DuckyHelper

Free to start. The web app works in any browser, Chromebooks included; the Mac app can also draw on your real screen. [Try it free in your browser](https://app.duckyhelper.com/?utm_source=duckyhelper.com&utm_medium=for) or [Get the Mac app](https://duckyhelper.com/download/)