---
title: "Coder in 90 Classroom: the GitHub Classroom replacement"
description: "Autograded coding assignments on the GitHub you already use. Distributed, graded on every push, and explained. A leaner, GitHub-native alternative to Codio. Students never pay; their institution pays per student."
url: https://coderin90.com/
---

# The GitHub Classroom replacement

Coding assignments on the GitHub you already use. Distributed, auto-graded on every push, and explained. When a student fails, our AI tells them *why*. Students start real coding work faster, in the GitHub they already know, with nothing to install.

[See the plans](https://coderin90.com/pricing/) See how it works →

Paid by the institution · runs on your GitHub org

$0

Instructors never pay

¼

the per-student cost of a managed platform

0

lock-in, it’s just GitHub repos

The difference

## A red “Fail” isn’t feedback.  
*This* is.

Most tools show a score. Coder in 90 turns it into teaching. The AI reads the real test output and your course notes, then explains why it failed and what to look at next, with the output shown right beside it, so it’s verifiable, never a black box.

**Most autograders:** a score, and analytics that flag frustration

**AI quiz tools:** generated questions, not failure explanations

Coder in 90: explains why it failed and what to look at next

barbara → Recursion Lab

scored 38 / 100

Autograder output

```
FAILED test_base_case: RecursionError:
maximum recursion depth exceeded
1 passed, 4 failed
```

AI explanation

Your `fib()` never reaches a return, so it calls itself until Python gives up. Which inputs should stop the recursion, and what does your function do with them? Trace `fib(1)` by hand to see.

How it works

## Publish. Push. *Graded.*

Three steps on the GitHub you already use. No new IDE for your students, no platform to onboard onto.

01 · PUBLISH

### Point us at a template repo

One click installs the GitHub App on your org. We generate a private repo per student and add them as collaborators. Nothing to import.

02 · PUSH

### Students code and push

In their own editor or free Codespaces. A GitHub Actions workflow runs your tests on every push, the workflow they’ll use at work.

03 · GRADED

### Scores and explanations land

The cohort gradebook fills automatically. Failing students surface with the reason, and an AI explanation they can act on.

Where we fit

## Built for the GitHub  
you *already* use.

Coder in 90 is deliberately leaner than a full managed platform: no new IDE to onboard, no courseware to import. Instructors spend less time on setup, troubleshooting, and manual grading, and students get instant, actionable guidance on every push. If you want a managed cloud IDE with GPU/Jupyter or a big ready-made courseware library, a platform like Codio is the stronger fit, and we’ll happily say so.

[See how we compare to Codio →](https://coderin90.com/codio-alternative/)

## Bring your course over.

Set up a cohort in minutes, on the GitHub you already use. The institution pays per learner, and students never pay.

[See the plans](https://coderin90.com/pricing/) [Book a 15-min migration call](mailto:hello@coderin90.com?subject=Coder%20in%2090%20Classroom%20migration%20call)

Last updated November 8, 2026