Online Python Code Editor for Interviews

Open a shared Python editor, send the candidate a link, and solve the problem together: you both see the code, cursors, and the run result in real time. Free, no sign-up, no install — everything works in the browser.

Free, no sign-up

Code sample

def two_sum(nums, target):
    seen = {}
    for i, x in enumerate(nums):
        if target - x in seen:
            return [seen[target - x], i]
        seen[x] = i
    return []


print(two_sum([2, 7, 11, 15], 9))  # [0, 1]

Output

[0, 1]

What the editor does

  • Python 3.12: the code runs on the server in an isolated sandbox, so the version is the same for every participant, and everyone sees the output and errors.
  • Real-time collaborative editing: up to 5 participants in one session, with edits and cursors visible instantly.
  • The problem statement is written in Markdown right in the session, next to the code — the candidate never has to switch tabs.
  • Autotests: if the task has unit tests, you can run them from the session and immediately see how many passed.
  • After a free sign-in: a task bank, an interview mode with a task playlist and timers, candidate scoring, and interview history.

How to run the interview

  1. Click "Open the Python editor" — the session is created right away with sample code you can delete or build your task on.
  2. Write the problem statement in Markdown and send the link to the candidate. They need no sign-up: they enter a name and land straight in the editor.
  3. Ask the candidate to think out loud and run the code as they go. Provide input data directly in the code — the session has no keyboard input.

Typical interview tasks

  • Two Sum: find a pair of numbers with a given sum — a dictionary instead of a double loop, a conversation about O(n) complexity.
  • Check whether a sequence of brackets is valid using a stack.
  • Group anagram words by sorting their letters or with collections.Counter.
  • Reverse a linked list and detect a cycle in it with the two-pointer method.
  • Write a generator: your own version of range, or read a large file line by line without loading it into memory.
  • Write a decorator that times a function or caches its results, and compare it with functools.lru_cache.

Limitations

  • No keyboard input: input() gets no data, so define the data in the code — as a list, a string or function arguments.
  • A single run is limited to 3 seconds and 64 KB of output — enough for interview-sized problems, but not for long computations.

FAQ

Which Python version is used?
Python 3.12. The code runs on the server, so the version is the same for every participant and does not depend on what is installed on their computers.
Can I run unit tests?
Yes. If the task has tests, you can run them from the session and see how many passed. Your own tasks with tests and the task bank are available after a free sign-in.
Does the candidate need to sign up?
No. The candidate opens the link, enters a name, and sees the editor right away. You do not need to sign in either, unless you want to keep the interview history.
How do I pass input data to the program?
The session has no keyboard input. Provide data directly in the code: for example, call the function with the arguments you need, or describe test cases as a list and loop over it.

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