The Lazy Networker

REST API stands for Representational State Transfer Application Programming Interface.
It’s a standard way for two systems to communicate over the web (HTTP/HTTPS) — often between a client (like Python script or Ansible) and a server (like a network device or SDN controller).

In simple terms:
👉 A REST API allows you to interact with a system (get data, configure, update, or delete something) using HTTP requests — just like how your browser communicates with websites.

⚙️ Why REST APIs Matter in Networking

In modern networks:

• Devices (Cisco, Juniper, Fortinet, etc.) and controllers (like OpenDaylight, Cisco DNA Center, VMware NSX) expose REST APIs.
• Engineers can automate tasks (like getting interface status, pushing configurations, or monitoring health) using API calls instead of manual CLI.

Example:
Instead of logging into 50 routers to check interface status,
you can run one Python script that uses REST APIs to fetch all interface data.

🧩 Key Concepts of REST API

🔠 Common HTTP Methods

🧾 Typical REST API Request Structure

A REST API request looks like this:

Method: GET
URL: https://192.168.1.1/api/v1/interfaces
Headers:
    Content-Type: application/json
    Authorization: Bearer <token>

Response (from device or server):

{
  "interfaces": [
    {"name": "GigabitEthernet0/0", "status": "up"},
    {"name": "GigabitEthernet0/1", "status": "down"}
  ]
}

💡 Key Characteristics of REST APIs

• Stateless: Each request is independent; the server doesn’t remember previous ones.
• Uses HTTP verbs: GET, POST, PUT, DELETE, etc.
• Uses URIs to identify resources.
• Supports multiple data formats: Commonly JSON, sometimes XML.
• Client-Server separation: Clear boundary between what requests and what responds.
• Cacheable: Responses can be cached for performance.

🧰 Common Tools to Work with REST APIs

🐍 Example: Python Script Using REST API

import requests
import json

url = "https://192.168.1.1/api/v1/interfaces"
headers = {
    "Content-Type": "application/json",
    "Authorization": "Bearer your_token_here"
}

response = requests.get(url, headers=headers, verify=False)
data = response.json()

for interface in data["interfaces"]:
    print(interface["name"], "-", interface["status"])

✅ This script retrieves interface status from a network device that supports REST APIs.

🌐 Example REST API Endpoints (Networking)

✅ Benefits of Using REST APIs

• Automation: Eliminate manual configuration
• Integration: Connect network, cloud, and monitoring systems
• Speed: Fast configuration and data collection
• Consistency: Apply uniform settings across devices
• Scalability: Manage hundreds of devices easily

🧭 Summary