Go Online Compiler | Free Online Compiler

Code

package main

import "fmt"

func main() {
    fmt.Println("Hello, Go!")
}

STDIN (optional)

Args (space separated)

Output

What Is the Go Online Compiler?

This tool lets you compile and run Go programs directly in your browser without installing the Go toolchain on your machine. Whether you are learning Go for the first time or quickly testing an idea, this compiler provides a fast way to write and execute Go code online.

Your code must follow standard Go conventions, starting with package main and including a func main() entry point. You can import any package from the Go standard library, including fmt, strings, math, sort, strconv, and many others.

All code executes on a remote sandboxed server powered by the Piston API. Your browser sends the source code to the server, which compiles and runs it inside an isolated container, then returns the output. This gives you a safe and reliable execution environment with no local setup required.

How It Works

Write your Go code in the editor panel. The editor starts with a simple "Hello, Go!" example, but you can replace it with any valid Go program that uses package main.
Provide input in the STDIN field if your program reads from standard input using fmt.Scanln, fmt.Scan, bufio.NewReader, or similar functions. Leave this field empty if your program does not require input.
Add command-line arguments in the Args field if your program reads from os.Args. Enter arguments separated by spaces.
Click the Run button to send your code to the Piston execution server. The server first compiles your Go source code, then executes the resulting binary and captures all output.
View the results in the Output panel. You will see everything your program prints to standard output, along with any compilation errors or runtime panics if something goes wrong.

Step-by-Step Example

Suppose you want to write a program that reads a name from standard input and prints a greeting. Here is how you would do it using this compiler:

First, type the following code into the editor panel:

package main

import "fmt"

func main() {
    var name string
    fmt.Scanln(&name)
    fmt.Println("Hello,", name, "- welcome to Go!")
}

Next, go to the STDIN field and type a name, for example Alice. This value will be read by fmt.Scanln when the program runs.

Now click the Run button. The compiler first builds your Go source code, then executes it with the provided input. After a moment, the Output panel displays the result:

Hello, Alice - welcome to Go!

If you change the STDIN value to a different name and click Run again, the output updates accordingly. This workflow makes it easy to test different inputs without modifying your code.

Use Cases

Learning Go syntax and standard library. Beginners can experiment with variables, types, control flow, slices, maps, structs, and interfaces in a zero-setup environment.
Testing concurrency patterns. Try out goroutines, channels, wait groups, and mutexes to understand Go concurrency without needing a local installation.
Practicing algorithms and data structures. Implement sorting algorithms, tree traversals, graph searches, and other common problems with immediate feedback from the output panel.
Preparing for coding interviews. Many interview questions can be solved in Go. Use this compiler to practice problems, test edge cases, and refine solutions quickly.
Trying Go syntax and language features. Quickly test how defer works, experiment with error handling patterns, explore type embedding, or verify how slices behave when appended to.

Limitations and Notes

Single file execution only. This compiler runs a single Go file (main.go). Multi-file projects and separate packages are not supported.
Package main is required. Your code must declare package main and include a func main() entry point, following standard Go program structure.
No go modules support. The go.mod file and module system are not available. You cannot import third-party packages from external repositories.
Go standard library is available. You can import and use packages like fmt, strings, math, sort, strconv, encoding/json, sync, and other standard library packages.
No network access. The sandboxed environment does not allow outgoing network connections. HTTP clients and TCP/UDP operations will not work.
Execution timeout applies. Programs that take too long or enter infinite loops are terminated automatically to prevent resource exhaustion.
No goroutine debugging. While goroutines and concurrency primitives work, there is no debugger or race detector available. Use print statements to trace concurrent behavior.

Frequently Asked Questions

What Go version does this compiler use?

It uses the latest available Go version provided by the Piston execution engine.

Can I use goroutines?

Yes, Go concurrency primitives including goroutines, channels, and sync packages work in this compiler.

Can I import standard library packages?

Yes, you can import standard library packages such as fmt, strings, math, sort, and others.

Can I use third-party packages?

No, third-party packages are not available. There is no go modules support in this environment.

Does this support go modules?

No, this compiler runs a single Go file only. Go modules and multi-file projects are not supported.

Can I use fmt.Scanln for input?

Yes, provide your input in the STDIN field and it will be available to fmt.Scanln and other reading functions.

Is there a build step?

Yes, Go code is compiled before running. You will see compilation errors if your code has syntax or type issues.

Can I use structs and interfaces?

Yes, the full Go type system is available including structs, interfaces, methods, and type assertions.

Go Compiler