---
name: http_post_json
kind: function
lang: go
domain: infra
version: "1.0.0"
purity: impure
signature: "func HttpPostJSON(url string, body any, headers map[string]string, timeout time.Duration) (map[string]any, error)"
description: "POST request con body JSON serializado con json.Marshal. Agrega Content-Type: application/json y Accept: application/json. Retorna error con status code si >= 400."
tags: [http, json, post, client, network, stdlib, infra]
uses_functions: []
uses_types: []
returns: []
returns_optional: false
error_type: "error_go_core"
imports: ["bytes", "encoding/json", "fmt", "io", "net/http", "time"]
params:
  - name: url
    desc: "URL del endpoint HTTP"
  - name: body
    desc: "datos a serializar como JSON en el cuerpo de la solicitud"
  - name: headers
    desc: "mapa de headers custom a fusionar con los headers por defecto"
  - name: timeout
    desc: "duracion maxima para completar la solicitud"
output: "mapa con la estructura JSON decodificada del response"
tested: true
tests:
  - "httptest.Server recibe body correcto"
  - "Status 201 → exito"
  - "Status 500 → error con body parcial"
test_file_path: "functions/infra/http_post_json_test.go"
file_path: "functions/infra/http_post_json.go"
---

## Ejemplo

```go
result, err := HttpPostJSON(
    "https://api.example.com/users",
    map[string]any{"name": "Alice", "role": "admin"},
    map[string]string{"X-Api-Key": "secret"},
    10*time.Second,
)
if err != nil {
    return nil, err
}
fmt.Println(result["id"])
```

## Notas

Solo usa stdlib. El body acepta `any` y se serializa con json.Marshal. Headers custom se fusionan con Content-Type y Accept por defecto. El error incluye los primeros 200 bytes del body de respuesta.