JSON & HTTP

Python uses json and requests/flask/fastapi. Go has JSON and HTTP in the standard library — production-grade, no third-party packages needed. This is where Go's practical value becomes immediately obvious.

JSON

import json

data = {"name": "Alice", "score": 95}
s = json.dumps(data)
parsed = json.loads(s)

type User struct {
    Name  string `json:"name"`
    Score int    `json:"score"`
}

u := User{Name: "Alice", Score: 95}
b, _ := json.Marshal(u)          // []byte
var parsed User
json.Unmarshal(b, &parsed)       // fills struct

Struct tags (`json:"name"`) control serialization. omitempty skips zero values. - excludes a field entirely.

type Event struct {
    ID        string  `json:"id"`
    Timestamp int64   `json:"ts"`
    Payload   any     `json:"payload,omitempty"`  // skip if nil
    Internal  string  `json:"-"`                  // never serialize
}

HTTP Server

package main

import (
    "encoding/json"
    "net/http"
)

func handleHealth(w http.ResponseWriter, r *http.Request) {
    w.Header().Set("Content-Type", "application/json")
    json.NewEncoder(w).Encode(map[string]string{"status": "ok"})
}

func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("GET /health", handleHealth)       // Go 1.22+ pattern
    mux.HandleFunc("POST /api/events", handleCreate)

    http.ListenAndServe(":8080", mux)
}

HTTP Client

func fetchUser(id string) (*User, error) {
    resp, err := http.Get(fmt.Sprintf("https://api.example.com/users/%s", id))
    if err != nil {
        return nil, fmt.Errorf("fetching user: %w", err)
    }
    defer resp.Body.Close()

    var u User
    if err := json.NewDecoder(resp.Body).Decode(&u); err != nil {
        return nil, fmt.Errorf("decoding: %w", err)
    }
    return &u, nil
}

The Full Mapping Table

Reference sheet for translating Python concepts to Go.