[json] How do I send a JSON string in a POST request in Go

I tried working with Apiary and made a universal template to send JSON to mock server and have this code:

package main

import (

func main() {
    url := "http://restapi3.apiary.io/notes"
    fmt.Println("URL:>", url)

    s := napping.Session{}
    h := &http.Header{}
    h.Set("X-Custom-Header", "myvalue")
    s.Header = h

    var jsonStr = []byte(`
    "title": "Buy cheese and bread for breakfast."

    var data map[string]json.RawMessage
    err := json.Unmarshal(jsonStr, &data)
    if err != nil {

    resp, err := s.Post(url, &data, nil, nil)
    if err != nil {
    fmt.Println("response Status:", resp.Status())
    fmt.Println("response Headers:", resp.HttpResponse().Header)
    fmt.Println("response Body:", resp.RawText())


This code doesn't send JSON properly, but I don't know why. The JSON string can be different in every call. I can't use Struct for this.

This question is related to json rest go apiary

The answer is

you can just use post to post your json.

values := map[string]string{"username": username, "password": password}

jsonValue, _ := json.Marshal(values)

resp, err := http.Post(authAuthenticatorUrl, "application/json", bytes.NewBuffer(jsonValue))

In addition to standard net/http package, you can consider using my GoRequest which wraps around net/http and make your life easier without thinking too much about json or struct. But you can also mix and match both of them in one request! (you can see more details about it in gorequest github page)

So, in the end your code will become like follow:

func main() {
    url := "http://restapi3.apiary.io/notes"
    fmt.Println("URL:>", url)
    request := gorequest.New()
    titleList := []string{"title1", "title2", "title3"}
    for _, title := range titleList {
        resp, body, errs := request.Post(url).
            Set("X-Custom-Header", "myvalue").
            Send(`{"title":"` + title + `"}`).
        if errs != nil {
        fmt.Println("response Status:", resp.Status)
        fmt.Println("response Headers:", resp.Header)
        fmt.Println("response Body:", body)

This depends on how you want to achieve. I made this library because I have the same problem with you and I want code that is shorter, easy to use with json, and more maintainable in my codebase and production system.

If you already have a struct.

import (

// .....

type Student struct {
    Name    string `json:"name"`
    Address string `json:"address"`

// .....

body := &Student{
    Name:    "abc",
    Address: "xyz",

payloadBuf := new(bytes.Buffer)
req, _ := http.NewRequest("POST", url, payloadBuf)

client := &http.Client{}
res, e := client.Do(req)
if e != nil {
    return e

defer res.Body.Close()

fmt.Println("response Status:", res.Status)
// Print the body to the stdout
io.Copy(os.Stdout, res.Body)

Full gist.

Examples related to json

Use NSInteger as array index Uncaught SyntaxError: Unexpected end of JSON input at JSON.parse (<anonymous>) HTTP POST with Json on Body - Flutter/Dart Importing json file in TypeScript json.decoder.JSONDecodeError: Extra data: line 2 column 1 (char 190) Angular 5 Service to read local .json file How to import JSON File into a TypeScript file? Use Async/Await with Axios in React.js Uncaught SyntaxError: Unexpected token u in JSON at position 0 how to remove json object key and value.?

Examples related to rest

Access blocked by CORS policy: Response to preflight request doesn't pass access control check Returning data from Axios API Access Control Origin Header error using Axios in React Web throwing error in Chrome JSON parse error: Can not construct instance of java.time.LocalDate: no String-argument constructor/factory method to deserialize from String value How to send json data in POST request using C# How to enable CORS in ASP.net Core WebAPI RestClientException: Could not extract response. no suitable HttpMessageConverter found REST API - Use the "Accept: application/json" HTTP Header 'Field required a bean of type that could not be found.' error spring restful API using mongodb MultipartException: Current request is not a multipart request

Examples related to go

Has been blocked by CORS policy: Response to preflight request doesn’t pass access control check Go test string contains substring Golang read request body How to uninstall Golang? Decode JSON with unknown structure Access HTTP response as string in Go How to search for an element in a golang slice How to delete an element from a Slice in Golang How to set default values in Go structs MINGW64 "make build" error: "bash: make: command not found"

Examples related to apiary

How do I send a JSON string in a POST request in Go