python
from flask import Flask, request, jsonify
import tensorflow as tf
from transformers import TFGPT2LMHeadModel, GPT2Tokenizer
app = Flask(__name__)
Load pretrained model and tokenizer
tokenizer = GPT2Tokenizer.from_pretrained('gpt2')
model = TFGPT2LMHeadModel.from_pretrained('gpt2', pad_token_id=tokenizer.eos_token_id)
@app.route('/chat', methods=['POST'])
def chat():
data = request.get_json()
user_input = data['message']