Online Go compiler
This compiles your Go with the real toolchain, inside your browser. Your code never leaves this tab.
Press Run. The Go 1.27 engine (about 14 MB) downloads once on your first run, then stays cached.
// Free tool
This compiles your Go with the real toolchain, inside your browser - cmd/compile and cmd/link built for WebAssembly, not a hosted playground on a server somewhere. Goroutines, channels, generics and most of the standard library work exactly as they do locally.
Nothing you type is sent to a server. Your code is saved only in this browser, the engine is downloaded once and cached, and once it has loaded the page keeps running your code with the network off. No account, no sign-in, no limit on how many times you press Run.
// What you get
Go 1.27 (cmd/compile + cmd/link), in a browser tab
The real Go compiler and linker, built for WebAssembly. Your program is compiled to a wasm binary in the tab and then executed - it is not interpreted and it is not a translation of Go into something else.
What it supports
- Go 1.27, including generics, goroutines, channels, defer and panic or recover.
- Most of the standard library: fmt, strings, strconv, slices, maps, sort, time, sync, math, errors, bufio, bytes, encoding/json, regexp and more.
- Compiler errors reported with the file, line and column the compiler gave them, not a generic failure.
What it does not
- No network and no filesystem: net, net/http and os/exec have nothing to talk to inside a browser tab.
- A program is stopped after 10 seconds, which is long enough for anything except an unbounded loop.
- One goroutine at a time. The sandbox is single-threaded, so goroutines interleave rather than run in parallel - the semantics are right, the wall-clock speedup is not there.
// Why it runs here
Your code never leaves the tab
Most online compilers send your code to a server, run it in a container, and send the output back. That means a queue when the site is busy, a hard cap on how long your program may run, and a copy of your code on someone else's disk. This one downloads the compiler instead, once, and runs everything locally from then on.
No upload, no account
- The compiler is fetched once and cached; your source is never sent anywhere.
- Nothing is stored on our side. Your code is kept in this browser only, so it is still here when you come back.
- Once the engine has loaded, it keeps running with the network off, which a hosted sandbox cannot do.
Then practice it for real
- A runner tells you what your code printed. It cannot tell you whether you have learned anything.
- Prepshotz runs the same engines against real test cases and grades the result.
- Practice Go with graded problems →
// The other nine
Every language we run, free
// Questions
Go in the browser - FAQ
01Is this the real Go compiler?
Yes. cmd/compile and cmd/link from Go 1.27 are themselves compiled to WebAssembly and run in your tab, so your program is built into a real binary and then executed. It is not an interpreter and not a Go-to-JavaScript translation, which is why compiler errors read exactly as they do on your machine.
02Why is the first run slower than the ones after it?
The first Run downloads the compiler, the linker and the standard library - about 14 MB - and that is cached for a year afterwards. Every run after the first is a compile and a link, which usually takes under a second.
03Can I use goroutines?
Yes, and they behave correctly: WaitGroups, channels, select and mutexes all work. The sandbox is single-threaded, so goroutines interleave on one thread rather than running on several cores - concurrency is real, parallel speedup is not.
04Does my code get uploaded anywhere?
No. The compiler runs inside your browser tab, so your code never leaves your machine. There is no server to send it to and nothing is logged on our side. Your code is kept only in this browser, and a share link carries it inside the link itself.
05Is it really free, and do I need an account?
Yes, and no. Every tool here runs without an account, a card, or a sign-in. They are free because they cost us nothing per run: the compiler is downloaded to your browser once and your own machine does the work.