What methods of data transfer from server to client do you know?

Main methods of data transfer from server to client:

• HTTP responses with body: sending data in JSON, XML, HTML, plain text formats.
• WebSocket: a bidirectional channel for real-time data exchange.
• Server-Sent Events (SSE): one-way transmission of events from server to client.
• Download files: transferring files via HTTP with Content-Disposition headers.
• Cookies and sessions: transmitting state via HTTP headers.

Example of sending JSON in Python using Flask:

from flask import Flask, jsonify
app = Flask(__name__)

@app.route('/data')
def data():
    return jsonify({'key': 'value'})

if __name__ == '__main__':
    app.run()