ESM vs CommonJS — The SDK uses ESM imports by default: import { SinchClient } from "@sinch/sdk-core". For CommonJS, use const { SinchClient } = require("@sinch/sdk-core").

Project-Scoped Auth (Conversation, Numbers, Fax, EST, etc.)

import { SinchClient } from '@sinch/sdk-core';

const sinch = new SinchClient({
  projectId: 'YOUR_PROJECT_ID',
  keyId: 'YOUR_KEY_ID',
  keySecret: 'YOUR_KEY_SECRET',
});

Setting the Conversation API Region

The region should be set explicitly for Conversation API usage. Not yet enforced in SDK v1 for backward compatibility, but recommended.

import { SinchClient, ConversationRegion } from '@sinch/sdk-core';

const sinch = new SinchClient({
  projectId: 'YOUR_PROJECT_ID',
  keyId: 'YOUR_KEY_ID',
  keySecret: 'YOUR_KEY_SECRET',
  conversationRegion: ConversationRegion.EUROPE, // us, eu, or br
});

Application-Scoped Auth (Voice, Verification)

App credentials only:

import { SinchClient } from '@sinch/sdk-core';

const sinch = new SinchClient({
  applicationKey: 'YOUR_APP_KEY',
  applicationSecret: 'YOUR_APP_SECRET',
});

Combined project + app credentials (multi-product):

import { SinchClient } from '@sinch/sdk-core';

const sinch = new SinchClient({
  projectId: 'YOUR_PROJECT_ID',
  keyId: 'YOUR_KEY_ID',
  keySecret: 'YOUR_KEY_SECRET',
  applicationKey: 'YOUR_APP_KEY',
  applicationSecret: 'YOUR_APP_SECRET',
});