Practice coding online, free
Write and run Python, Java, C++, JavaScript or SQL in your browser. Nothing to install, works on a phone, and a free account is all it takes. Below is exactly what is free and what is not — no surprises.
What’s free and what isn’t
| What | Signed out | Free account | Membership |
|---|---|---|---|
| Read every compiler page | Yes | Yes | Yes |
| Run code in 5 languages | — | Yes | Yes |
| Daily run limit | — | 300 | 300 |
| Graded exercises, hidden tests | — | Yes | Yes |
| Full course lessons | — | Preview | Yes |
| Verifiable certificate | — | — | Yes |
| Price | ₹0 | ₹0 | ₹600/mo |
What actually runs your code
Real toolchains, not simulations — which is why the error messages match what you would see locally:
- • Python 3.12 — CPython compiled to WebAssembly
- • Java 21 — a real JDK, so javac reports the genuine compiler errors
- • C++17 — GCC 13
- • JavaScript — QuickJS engine
- • SQL — genuine PostgreSQL, so ILIKE, JSONB and window functions behave correctly
Common questions
Where can I practice coding online for free without installing anything?
You can use the free online compilers on this site for Python, Java, C++, JavaScript and SQL. Nothing to install, and it works on a phone. Running code needs a free account — no card, no trial — which also unlocks graded exercises with hidden test cases.
Is it really free, or is there a catch?
Running code is free — it needs a free account, with a daily cap so the service stays available for everyone. No card is asked for at any point. Full course access is a paid membership at ₹600/month, which covers every path rather than charging per course.
Can I practice DSA online in Java or C++ specifically?
Yes. The DSA path teaches every algorithm in Python, Java and C++, and its exercises run in whichever of those you choose — which matters because most interviews in India and Germany are conducted in Java or C++.
Do I need a laptop, or can I practice on a phone?
A phone works. The editor supports touch and everything compiles on our servers, so nothing depends on your device's power or on installing a toolchain.
How is this different from just using an online compiler?
An online compiler runs your code and shows the output. Here the exercises also check your solution against hidden test cases and tell you which ones fail, which is the difference between running code and knowing it is correct.
Start with the compiler
Nothing to install, and the account is free — no card, no trial. It takes about a minute and unlocks graded exercises too.