👉 Splash is a JavaScript rendering service built on top of QT WebKit.

It is mainly used in web scraping when you need to extract data from pages that require JavaScript execution (like dynamic content).

💡 Think of it as a lightweight browser you can control with code 🖥️🤖.

⚙️ How Splash Works?

🔹 Normally, libraries like Requests + BeautifulSoup can only fetch static HTML.
🔹 But many modern websites load content dynamically (using JS frameworks like React, Angular, Vue).
🔹 Splash renders the page just like a browser → executes JS → returns the final HTML, images, or even screenshots.

🧩 Key Features of Splash

🎨 1. JavaScript Rendering

• Executes JavaScript just like Chrome or Firefox.

• Helps extract hidden data from dynamic websites.

📸 2. Screenshots & Rendering

• Take screenshots of the page.

• Render specific elements only.

🔄 3. HTML & HAR Export

• Export the rendered HTML.

• Export HAR (HTTP Archive) files for debugging requests.

📜 4. Scriptable with Lua

• Control Splash using Lua scripts for advanced automation (clicks, scrolls, etc.).

📦 5. Docker-Friendly

• Runs inside Docker containers for easy deployment.

🔑 Basic Usage

1️⃣ Install via Docker 🐳

docker run -p 8050:8050 scrapinghub/splash

2️⃣ Simple HTTP API Call 🌐

Fetch HTML after JS rendering:

http://localhost:8050/render.html?url=https://example.com

3️⃣ Python Example with Requests 🐍

import requests

url = 'http://localhost:8050/render.html'
params = {'url': 'https://example.com', 'wait': 2}

response = requests.get(url, params=params)
print(response.text)

👉 Here wait=2 allows 2 seconds for JavaScript to load.

🌟 Advantages of Splash

✅ Handles JavaScript-heavy websites ⚡
✅ Can be automated with Lua scripting 🤖
✅ Exports screenshots, HAR, HTML 📝
✅ Works well with Scrapy-Splash middleware 🕷️

⚠️ Limitations of Splash

⚡ Slower than static scraping (because it renders JS)
⚡ High CPU & memory usage (since it behaves like a browser)
⚡ Limited JavaScript support compared to modern browsers like Chrome/Playwright
⚡ Needs Docker setup for production

🌈 Splash in Real Life

Imagine you want to scrape a stock website 📈 that loads prices using JavaScript.

• Without Splash → you’ll just get an empty <div>.

• With Splash → you’ll get the fully rendered page with stock prices 🔥

🎨 Visual Flow

Client (Scrapy/Python) → Sends request to Splash → Splash renders JS → Returns final HTML/JSON/Screenshot → Data Extracted

👉 In short:
Splash = Mini browser for scraping JavaScript-heavy sites 🌐🕸️