Learnex is an AI study platform that turns your own uploaded notes, PDFs, and lecture slides into flashcards, quizzes, and AI-narrated video lessons — all generated from and traceable back to your material.

Yes. The free plan includes basic quizzes, flashcards, and audio lessons on one subject. Paid plans (Explorer at $4.99/mo and Master at $7.99/mo) unlock unlimited subjects and full AI video lessons. Students with a .edu email get 20% off paid plans.

How is Learnex different from Quizlet?

Quizlet is built around manually-made and community flashcard sets. Learnex generates flashcards, quizzes, and video lessons automatically from your own uploaded material, so everything maps directly to what you're actually studying.

How is Learnex different from Anki?

Anki is a manual spaced-repetition flashcard tool — you create the cards yourself. Learnex automates the entire process: upload your PDF or notes and it generates flashcards, quizzes, explanations, and video lessons from them automatically.

What file types does Learnex support?

You can upload PDFs, images of lecture slides, and scanned handwritten notes. Learnex uses AI vision to extract and understand the material regardless of format.

Does Learnex use my notes to train AI models?

No. Your uploaded material is processed only to generate your own study content and is never used to train AI models or shared with other users.

How long does it take to generate study materials?

Most uploads are processed within a few minutes. The AI generates topic explanations, quizzes, flashcards, and audio or video lessons automatically — you can start studying shortly after uploading.

Find the bug. Then see why it breaks.

Paste your code. Learnex pinpoints the faulty line, shows a failing test case and walks through execution step by step, so you can see what the program is really doing.

START FREE →

How to debug your code with the Learnex Code Lab

1
Paste your code and pick the language
Python, JavaScript or TypeScript, Java, C++, Go and Rust are supported.
2
Run Find My Bug
Learnex pinpoints the faulty line, names the type of defect and gives a failing test case: input, expected output and actual output.
3
Trace the execution
Step through the algorithm on a concrete input and watch variables and the call stack change. At key branches you are asked to predict what happens next.
4
Practise the fix
Try a Parsons-style challenge: a function skeleton with the key logic missing, checked against edge cases.

Built to teach debugging, not just patch your code

Exact-line bug finder

Off-by-one errors, unbounded recursion, modifying a list while iterating, null or undefined dereferences, integer-division traps and reference-versus-value mutation.

A failing test case every time

Input, expected output and actual output, so you can see the bug rather than take it on trust.

Execution trace with a live memory table

Follow variables like low, high and mid, plus call-stack frames, one step at a time.

Predict-the-next-step prompts

At critical branches the lab asks what happens next, training the mental model you need in exams and interviews.

Parsons-style scaffolding

Fill in the missing core logic of a clean skeleton and get a pass/fail matrix on edge cases.

Big-O and a rule of thumb

Time and space complexity for the code, plus a short exam-ready rule to avoid the same bug again.

Example: an off-by-one in binary search

This binary search looks fine but crashes on some inputs.

Student code

def binary_search(arr, target):

    low, high = 0, len(arr)          # <- faulty line: should be len(arr) - 1

    while low <= high:

        mid = (low + high) // 2

        if arr[mid] == target:

            return mid

        elif arr[mid] < target:

            low = mid + 1

        else:

            high = mid - 1

    return -1

Failing test case

Input:    arr = [1, 3], target = 5

Expected: -1

Actual:   IndexError: list index out of range

Why it breaks

high starts one past the last valid index. With target 5, low becomes 2 and mid becomes 2, so arr[2] reads outside the list.

Fix and complexity

low, high = 0, len(arr) - 1      # Time O(log n), Space O(1)

Key Takeaway

Defect type: off-by-one boundary error. Rule of thumb: when the loop condition is low <= high, high must be the last valid index.

Frequently asked questions

How do I debug code step by step?

Reproduce the failure with a concrete input, then trace the variable values line by line until you find the first point where the actual state differs from what you expected. The Learnex Code Lab guides you through both parts: it pinpoints the faulty line, shows a failing test case and walks execution with a live memory table.

Which programming languages does the Code Lab support?

Python, JavaScript and TypeScript, Java, C++, Go and Rust are supported for the Find My Bug diagnostic.

Does the Code Lab run my code?

The trace is an AI-guided walkthrough built for learning. It is not a replacement for your compiler or debugger, so use it to understand what is going on, then confirm the behaviour in your own environment before you submit.

How is this different from asking a chatbot to fix my code?

A fixer hands back rewritten code. The Code Lab is built to teach: it locates the line, names the defect type, proves the problem with a failing case, and then asks you to predict and rewrite the logic yourself.

What is a Parsons problem?

A Parsons problem gives you a working structure with the key logic left out, so you practise writing the part that matters. In the Code Lab your answer is checked against edge cases and you see which tests pass and fail.

Is it okay to use this for assignments?

The Code Lab is designed to help you understand your own mistakes, not to write assignments for you. Check your course's rules on AI assistance before using any tool on graded work.

Related tools & labs

All Learnex Labs Math Mistake Finder Biology Pathway Simulator Socratic AI Tutor

Master the reasoning behind every answer

Practice the step-by-step logic exams actually test with Learnex Labs.