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Click-to-Call

Click-to-call enables your application to initiate phone calls on behalf of users. When triggered, the system first calls the user's registered devices, then connects them to the destination number.

Overview​

Click-to-call allows you to:

  • Add "Call" buttons next to customer phone numbers in your application
  • Enable one-click dialing from CRM records, support tickets, or contact lists
  • Track call activity through the call logs API

How It Works​

When you initiate a click-to-call:

  1. First leg: All of the user's registered devices (desk phones, softphones) ring simultaneously
  2. Answer: The user picks up any of their devices
  3. Second leg: The system dials the destination number
  4. Bridge: Both calls are connected together

This "call-first" approach ensures the user is ready before the customer's phone rings, providing a professional experience.

Initiating a Call​

Using the API​

Make a POST request to /v1/calls with the user ID and dial string:

Bash
curl -X POST https://api.dialstack.ai/v1/calls \
  -H "Authorization: Bearer sk_live_YOUR_SECRET_KEY" \
  -H "DialStack-Account: acct_01h2xcejqtf2nbrexx3vqjhp41" \
  -H "Content-Type: application/json" \
  -d '{
    "user": "user_01h2xcejqtf2nbrexx3vqjhp42",
    "dial_string": "+15551234567"
  }'

The API returns 202 Accepted immediately. The call is processed asynchronously.

Using the SDK​

JavaScript
import { loadDialstackAndInitialize } from '@dialstack/sdk-js';

const dialstack = await loadDialstackAndInitialize({
  publishableKey: 'pk_test_...',
  fetchClientSecret: async () => {
    const response = await fetch('/api/dialstack/session');
    const { client_secret, expires_at } = await response.json();
    return { clientSecret: client_secret, expiresAt: expires_at };
  },
});

// Initiate a call
await dialstack.calls.create({
  userId: 'user_01h2xcejqtf2nbrexx3vqjhp42',
  dialString: '+15551234567',
});

Request Parameters​

FieldTypeRequiredDescription
userstringYesThe user whose devices will ring first. user_id is accepted as a deprecated alias
dial_stringstringYesThe number to dial (see formats below)

Dial String Formats​

The dial_string parameter accepts several formats:

FormatExampleDescription
E.164+15551234567International format (recommended)
Local5551234567Normalized based on account region
Extension1001Internal extension dialing
Emergency911Emergency services

Server-Side Implementation​

Here's how to implement a click-to-call endpoint in your backend:

Node.js / Express​

JavaScript
import express from 'express';

const app = express();
app.use(express.json());

// Your platform's API key
const DIALSTACK_API_KEY = process.env.DIALSTACK_API_KEY;

app.post('/api/call', async (req, res) => {
  const { userId, phoneNumber, accountId } = req.body;

  try {
    const response = await fetch('https://api.dialstack.ai/v1/calls', {
      method: 'POST',
      headers: {
        Authorization: `Bearer ${DIALSTACK_API_KEY}`,
        'DialStack-Account': accountId,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        user: userId,
        dial_string: phoneNumber,
      }),
    });

    if (response.status === 202) {
      res.json({ success: true, message: 'Call initiated' });
    } else {
      const error = await response.json();
      res.status(response.status).json(error);
    }
  } catch (error) {
    res.status(500).json({ error: 'Failed to initiate call' });
  }
});

Python / Flask​

Python
from flask import Flask, request, jsonify
import requests
import os

app = Flask(__name__)

DIALSTACK_API_KEY = os.environ.get('DIALSTACK_API_KEY')

@app.route('/api/call', methods=['POST'])
def initiate_call():
    data = request.json

    response = requests.post(
        'https://api.dialstack.ai/v1/calls',
        headers={
            'Authorization': f'Bearer {DIALSTACK_API_KEY}',
            'DialStack-Account': data['account_id'],
            'Content-Type': 'application/json'
        },
        json={
            'user': data['user_id'],
            'dial_string': data['phone_number']
        }
    )

    if response.status_code == 202:
        return jsonify({'success': True, 'message': 'Call initiated'})
    else:
        return jsonify(response.json()), response.status_code

Frontend Integration​

Add click-to-call buttons to your UI:

JavaScript
function CustomerCard({ customer, currentUser, accountId }) {
  const [calling, setCalling] = useState(false);

  async function handleCall() {
    setCalling(true);
    try {
      const response = await fetch('/api/call', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          userId: currentUser.dialstackUserId,
          phoneNumber: customer.phone,
          accountId: accountId,
        }),
      });

      if (response.ok) {
        // Show "Calling..." indicator
        showNotification('Calling ' + customer.name);
      }
    } finally {
      setCalling(false);
    }
  }

  return (
    <div className="customer-card">
      <h3>{customer.name}</h3>
      <p>{customer.phone}</p>
      <button onClick={handleCall} disabled={calling}>
        {calling ? 'Calling...' : 'Call'}
      </button>
    </div>
  );
}

Error Handling​

StatusErrorDescription
400user_id is requiredMissing user in request
400dial_string is requiredMissing dial_string in request
400Invalid user_id formatuser is not a valid user ID
401UnauthorizedInvalid or missing API key/session
404User not foundUser doesn't exist in the account

Best Practices​

DO​

  • Validate phone numbers before sending to the API
  • Show a loading state while the call is being initiated
  • Use E.164 format for phone numbers when possible
  • Log call attempts for troubleshooting

DON'T​

  • Don't expose your platform API key in client-side code
  • Don't allow arbitrary dial strings from user input without validation
  • Don't retry failed calls automatically (let the user decide)

Monitoring Calls​

After initiating a call, you can track its progress:

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