Real-time email validation API for signup forms

// server.js (Express Route)
const timeoutMs = 5000; // adjust to what your form can tolerate

app.post('/api/signup', async (req, res) => {
  const { email, password } = req.body;

  try {
    const apiRes = await fetch('https://api.giggal.ai/v1/verify', {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${process.env.GIGGAL_API_KEY}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({ email }),
      signal: AbortSignal.timeout(timeoutMs), // fail-open timeout
    });

    const result = await apiRes.json();
    if (result.success) {
      const { status, details } = result.data;

      // Decision checks
      if (status === 'undeliverable') {
        return res.status(400).json({ error: 'This email address does not exist.' });
      }
      if (details.attributes.disposable) {
        return res.status(400).json({ error: 'Disposable email addresses are not accepted.' });
      }
    }
  } catch (err) {
    // Fail open: log timeout and let user proceed
    console.warn('Email check timed out, failing open:', err.message);
  }

  // Create user in database
  const user = await db.users.create({ email, password });
  return res.json({ success: true, userId: user.id });
});

# app.py (Flask Route)
import os, requests
from flask import Flask, request, jsonify

app = Flask(__name__)
timeout_seconds = 5  # adjust to what your form can tolerate

@app.route("/api/signup", methods=["POST"])
def signup():
    email = request.json.get("email")

    try:
        resp = requests.post(
            "https://api.giggal.ai/v1/verify",
            headers={"Authorization": f"Bearer {os.environ['GIGGAL_API_KEY']}"},
            json={"email": email},
            timeout=timeout_seconds  # fail open on timeout
        )
        data = resp.json().get("data", {})
        if data.get("status") == "undeliverable":
            return jsonify({"error": "Email address is invalid."}), 400
        if data.get("details", {}).get("attributes", {}).get("disposable"):
            return jsonify({"error": "Disposable emails are prohibited."}), 400
    except requests.exceptions.RequestException:
        # Fail open: proceed with signup on timeout
        pass

    # Complete user registration
    return jsonify({"success": True})

// Frontend form submit handler
const form = document.querySelector('#signup-form');

form.addEventListener('submit', async (e) => {
  e.preventDefault();
  const email = document.querySelector('#email-input').value;

  const res = await fetch('/api/signup', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ email }),
  });

  const payload = await res.json();
  if (!res.ok) {
    showFormError(payload.error); // Show friendly user feedback
  } else {
    redirectToDashboard();
  }
});