Like the title said, in this article we will do debugging go application with VS Code and Go extension.

Setup simple application

We will create a simple http server that says hello

// main.go
package main

import (

func main() {
    http.HandleFunc("/", helloServer)
    http.ListenAndServe(":8080", nil)

func helloServer(w http.ResponseWriter, r *http.Request) {
    name := r.URL.Path[1:]
    fmt.Fprintf(w, "Hello, %s!", name)


For example, you may want to debug the value of the name variable from the application above then we have two options here to debug our http server.

Option 1: Debugging with test

Step 1: Let’s write our test

// main_test.go
package main

import (

func Test_helloServer(t *testing.T) {
    request, _ := http.NewRequest(http.MethodGet, "/Foo", nil)
    response := httptest.NewRecorder()

    helloServer(response, request)

    got := response.Body.String()
    want := "Hello, Foo!"
    if got != want {
        t.Errorf("got %q, want %q", got, want)

Step 2: Add breakpoint

Now we have our test for helloServer, next step we need to add a breakpoint right after this line name := r.URL.Path[1:] by click on the left of expect line number or move the pointer to the expect line number and press F9 to toggle a breakpoint.

Step 3: Debug test

Finally, click on debug test to see the result:

Here, we can see the value of the name variable is Foo in the left panel or hover mouse on the name variable

Option 2: Debug with http request using dlv

Step 1: Install dlv

Open the Command Palette (Ctrl+Shift+P or Command+Shift+P), select Go: Install/Update Tools, and select dlv

Step 2: Add launch configuration

Create .vscode/launch.json in your root project folder and put this content into it

    "version": "0.2.0",
    "configurations": [
            "name": "Launch",
            "type": "go",
            "request": "launch",
            "mode": "auto",
            "program": "${fileDirname}",
            "env": {},
            "args": []

Note: If your main.go file inside sub folder like cmd/api/main.go, you may want add this config to launch.json file to set current working directory to root project folder: "cwd": "${workspaceRoot}"

Step 3: Add breakpoint

This step is the same as add breakpoint like Option 1

Step 4: Run and Debug

Open the main.go file and press F5 and you ready to “Go” :)
Next, open your favorite terminal and enter curl localhost:8080/Baz for example. Now you can see the debug result:

Source code

You can find source code for this article at GitHub.


Above are two debug options for Go using VS Code which is very useful. For me, I prefer to cover as many tests as possible (Option 1), but when I need to debug a full flow of a request then Option 2 will be the best choice. And you? Which method do you use for debugging Go code?