In-browser judge · 6 tracks · 121 quests
Reading code
is not writing
code.
Praxis gives you a brief and an empty editor. You build the thing. A judge runs your code against real checks and tells you exactly which ones you haven't met yet — no answer key, no video to nod along to.
- A <button> exists and reads “Submit”
- Its accessible name is announced to screen readers
- Its background computes to emerald-600
- It stays keyboard-focusable with a visible ring
Score
6
Tracks
64
Syllabus topics
121
Judged quests
5/track
Free to solve
The loop
Three steps, then again tomorrow.
- 01
Read the brief
A short spec: what to build and what counts as done. No lecture, no 40-minute video — you can start typing in under a minute.
- 02
Build it your way
Write real HTML, CSS, JS, Python or SQL in a full editor. Checks test intent, not structure, so a different-but-correct solution still scores 100.
- 03
Let the judge answer
Your code runs in the browser and every check reports back individually. A failed check tells you what it wanted — never how to write it.
Curriculum
Six tracks. Every one runs in your browser.
HTML Mastery
structure the web — from first tag to full semantic pages
CSS Mastery
make it beautiful — selectors to animation, box model to grid
JavaScript Mastery
make it alive — from typeof to async/await
Python Mastery
real Python 3 in your browser — zero to decorators
SQL Mastery
talk to databases — real SQLite running in your browser
DSA Drills
data structures & algorithms — the interview classics, in Python
The workbench
Everything a practice session needs. Nothing it doesn't.
Python and SQLite, actually running
Not a simulation. Real CPython and a real SQLite database execute in the tab, so your loops, exceptions and queries behave the way they will on your machine.
Checks that test intent
Checks read computed styles, accessible names and program output — never your class names or DOM order. Solve it your way and still score 100.
A mentor that refuses to solve it
Hints point at the gap between what you wrote and what the check wanted. You never get handed the answer, because that isn't the part you need practice at.
Progress that follows you
Every attempt, score and streak syncs to your account. Close the tab mid-quest and your code is waiting on the next device.
Certificates you earn per track
A track certificate unlocks when every quest in it passes. It records what you actually completed, so it means something.
Sessions that fit a lunch break
Quests are sized in minutes, not hours. The daily streak rewards showing up rather than marathoning once a month.
Pricing
Pay once for a stretch of time. Never a surprise renewal.
A payment buys a fixed window of Pro. When it runs out you drop back to Free — nothing auto-charges, and extending stacks onto whatever time you have left.
The first quest takes about three minutes.
No card, no install, no onboarding tour. Open the editor and get something to pass.