Two good tools.
Different bets.
Codio built one platform for every course, a managed cloud IDE with a deep courseware library. We made a narrower bet: keep students in the GitHub they’ll use at work, autograde on every push, and explain the failures. Here’s where each one shines, so you can pick honestly.
The whole shortlist
Most instructors leaving GitHub Classroom are weighing five options, not two. Here they all are, with the concessions included.
| Capability | Coder in 90 | Codio | Classmoji | Classroom 50 | CodeGrade |
|---|---|---|---|---|---|
| Price | From $39/mo per instructor, students never pay | About $48 per student per semester | Free, open source | Free, self-hosted | Free under 50 students |
| Hosted convenience | Yes hosted, install one GitHub App | Yes full managed cloud IDE | No you host it yourself | No you run and patch the server | Yes hosted |
| Cohort analytics | Yes per-assignment and per-student | Yes keystroke-level | Emoji grading, TA auto-assign, resubmission, extension tokens | No | Yes rubric-based |
| AI-explained failures | Yes Unique to Coder in 90 | No score only | No its AI does quizzes, not failure explanation | No score only | No manual inline comments |
| Lock-in | None plain repos in your own org | Platform, IDE, and courseware | None GitHub-native, your own install | None it is your server | Assignments live in CodeGrade |
Competitor details are from their own public docs and change often, so check before you commit. If you can self-host, Classmoji is the closest thing to what we do: GitHub-native, free, and further along on the classroom mechanics. If you can self-host and do not need analytics, Classroom 50 is a fine choice. If your class is small and you grade by rubric, CodeGrade’s free tier will carry you. We built Coder in 90 for the instructor who wants hosted autograding, real cohort analytics, and an explanation attached to every failure.
Side by side
Coder in 90
- 2-week free trial. Students always free
- Students code in real GitHub repos: branches, PRs, CI
- AI explains every failed test, grounded in your notes
- Zero lock-in. Your repos, your org, walk away anytime
- Set up in an afternoon by installing one GitHub App
Codio
- One platform, every course, with a managed cloud IDE included
- Browser IDE so students start real coding work faster, nothing to install
- Auto-graded labs, rubric scoring, and keystroke-level analytics
- A large ready-made courseware library and LMS grade-sync
- GPU and Jupyter support for data and ML courses
Pick Codio if you want a managed cloud IDE with GPU/Jupyter, a big ready-made courseware library, or built-in plagiarism detection today. Pick Coder in 90 if you’d rather keep students on real GitHub, pay one flat instructor plan while students stay free, and give them an AI mentor that explains every failure.
A red “Fail” isn’t feedback.
This is.
Both platforms auto-grade. The gap is what a student sees when they fail. The Coder in 90 AI mentor reads the real test output and your course notes, then explains the failure and the fix, with the output shown right beside it, so it’s verifiable, never a black box. It’s the autograder that tutors.
FAILED test_base_case: RecursionError: maximum recursion depth exceeded 1 passed, 4 failed
fib() never reaches its base case, so it calls itself forever. Add if n <= 1: return n before the recursive call. That stops the infinite descent, and the other four tests pass.One flat plan.
Per instructor.
One flat plan per instructor. $39 to $199 a month by class size. Students never pay. 2-week free trial.
Before you switch
Is Coder in 90 a drop-in GitHub Classroom replacement?
Yes for the core workflow: roster, assignment distribution, autograding, and a gradebook. We rebuilt what GitHub Classroom actually did, on the same GitHub primitives, and added the AI mentor on top.
Do students have to pay?
No. Students never pay. One instructor pays a flat monthly plan from $39 to $199 depending on class size, and every student in that class is covered. Fair-use AI is included in the plan; a heavy class can add metered AI or bring its own provider key. Grading runs on GitHub Actions, and GitHub Codespaces has a free monthly allowance that covers typical coursework.
Can I move my existing GitHub Classroom assignments over?
They’re already GitHub repos, which is the whole point. You point them at Coder in 90, keep your history, and nothing is re-authored. We walk you through it before the August 28, 2026 shutdown.
Do you integrate with my LMS (Canvas, Moodle, Google Classroom)?
Not yet. Today the gradebook lives on screen in the instructor dashboard, per assignment and per student. CSV export and LTI 1.3 or Google Classroom grade passback are on the roadmap, built when an institution that needs them comes on board.
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