Selenium WebDriver Achitecture

What is Selenium WebDriver?
Selenium WebDriver is a set of open-source APIs, which provided the capabilities to interact with any of the modern web-browsers and then, in-turn to automate the user actions with that browser. It is an essential component of the Selenium family. As we know, Selenium is not an independent tool; rather, it is a collection of tools that make the Selenium suite, which was created when two projects Selenium RC and WebDriver were merged.

1. Client Libraries (Language Bindings)

👉 This is just your programming language support

Examples:

Java
Python
C#
JavaScript
Simple meaning:

“Selenium lets you write automation code in your favorite language.”

So you can say:

Java code → Selenium library understands it
Python code → Selenium library understands it
📡 2. Communication (JSON /W3C+ HTTP)

👉 This is how Selenium sends messages

Simple meaning:

“Your code talks to browser using messages sent over the internet format (HTTP + JSON)”

Think like:

You (Java code)
↓ message
Browser driver

Message looks like:

click button
open URL
type text
🚗 3. Browser Drivers

Examples:

ChromeDriver
GeckoDriver
Simple meaning:

“Each browser has its own helper program that understands Selenium commands”

So:

Chrome → ChromeDriver
Firefox → GeckoDriver

👉 This driver acts like a translator

🌍 4. Browsers

Examples:

Chrome
Firefox
Edge
Simple meaning:

“This is where your website actually opens and runs”

Browser must be installed because:

Selenium does NOT create browsers
It only controls existing browsers
🔁 Full flow (very simple)
Your Code (Java/Python)
↓
Selenium Library
↓
HTTP + JSON messages
↓
Browser Driver (ChromeDriver / GeckoDriver)
↓
Browser (Chrome / Firefox)

Selenium 4 - Selenium Manager:
👉 Selenium Manager is an internal feature of Selenium 4 WebDriver that automatically handles browser drivers.
Built inside Selenium 4 WebDriver library itself
⚙️** What it does**
✔ Detects installed browser version
✔ Downloads correct driver (ChromeDriver/GeckoDriver, etc.)
✔ Sets driver path automatically
✔ Removes need for System.setProperty()
❌ In Selenium 3
No Selenium Manager
You had to manually set:
System.setProperty("webdriver.chrome.driver", "path");