Bolt.new AI and Sinch integration: Step-by-Step Guide 2025

The direct answer: You integrate Bolt.new with Sinch the same way you integrate any external API inside a Bolt sandbox — by calling Sinch’s REST APIs (SMS, Voice, Conversations, WhatsApp, etc.) using your Sinch API key/secret stored as environment variables. Bolt.new does not have a native Sinch connector; you wire it manually with HTTP requests. Inside Bolt you build a small backend route (Node.js/Express) that calls Sinch’s REST endpoints, and your frontend or AI agent logic can trigger that route. Authentication uses the standard Sinch API Key + API Secret with HTTP Basic Auth or Bearer Token depending on the product you use.

 

What Bolt.new Actually Is

 

Bolt.new is a browser-based full‑stack coding environment. It is not a service that automatically “talks” to third‑party APIs. You integrate external systems exactly as you would in any small Node.js service: you call REST endpoints using fetch or axios, and you store credentials in environment variables.

So “Bolt + Sinch” = you writing code in Bolt that calls Sinch’s APIs.

 

The Required Sinch Concepts

 

• API Key & Secret: Provided in your Sinch dashboard. These authenticate requests.
• Sending Phone Number / Service ID: The number or channel you own in Sinch.
• REST Endpoint: The HTTPS URL you call to send SMS or messages.
• Webhook (Optional): URL in your Bolt backend that receives delivery receipts or inbound messages.

 

How to Set It Up in Bolt.new

 

You do three steps inside Bolt:

• Create environment variables (ex: SINCH_KEY, SINCH_SECRET, SINCH_SERVICE_PLAN_ID, SINCH_NUMBER).
• Add a backend route that calls the Sinch REST API.
• Test it from the built-in frontend or from server logs.

 

// Example: Node.js/Express route inside your Bolt.new codebase
// This sends an SMS using Sinch SMS REST API v1
// Make sure these env vars exist: SINCH_KEY, SINCH_SECRET, SINCH_SERVICE_PLAN_ID, SINCH_NUMBER

import express from 'express';
import fetch from 'node-fetch';

const router = express.Router();

router.post('/send-sms', async (req, res) => {
  const { to, message } = req.body;

  const sinchKey = process.env.SINCH_KEY;
  const sinchSecret = process.env.SINCH_SECRET;
  const planId = process.env.SINCH_SERVICE_PLAN_ID;
  const from = process.env.SINCH_NUMBER;

  const url = `https://sms.api.sinch.com/xms/v1/${planId}/batches`;

  try {
    const response = await fetch(url, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'Authorization': 'Basic ' + Buffer.from(`${sinchKey}:${sinchSecret}`).toString('base64')
      },
      body: JSON.stringify({
        from,
        to: [to],
        body: message
      })
    });

    const data = await response.json();
    res.json(data);

  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Failed to send SMS' });
  }
});

export default router;

 

How This Works in Practice

 

When your Bolt backend receives a POST to /send-sms, it forwards that request to Sinch’s SMS API using your authenticated Sinch credentials. Bolt itself is just your execution environment; the real work is the HTTP call to Sinch.

Your frontend (React/Vue/Next/etc.) inside Bolt can now simply call your own backend route:

 

// Example: calling your Bolt backend from frontend
await fetch('/send-sms', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ to: '+123456789', message: 'Hello from Sinch + Bolt!' })
});

 

Optional: Receiving Inbound Messages (Webhooks)

 

If you want inbound SMS or delivery receipts, Sinch will POST events to a webhook you specify. In Bolt, you simply expose an endpoint:

 

// webhook.js
router.post('/sinch-webhook', (req, res) => {
  console.log('Received Sinch event:', req.body); // inbound SMS or delivery report
  res.sendStatus(200);
});

Then you configure that URL in your Sinch dashboard. In production you’ll expose a public URL (Bolt preview URLs can work for testing, but are temporary).

 

Important Considerations

 

• Use environment variables for Sinch API credentials. Never hardcode keys.
• Bolt preview servers can sleep. For production you deploy the same code to a persistent server (Vercel, Netlify, Render, etc.).
• SMS regulations apply. Carriers require valid sender numbers and content rules.

 

This is exactly how you integrate Bolt.new with Sinch: direct REST API calls from a backend route, authenticated with your Sinch key/secret, triggered from your app or AI agent.