Sellsy (Client Credentials)

🚀 Quickstart
🔗 Useful links
🚨 API gotchas

Create an integration

Sign up for a free Nango account (here) if you haven’t already. Then navigate to Integrations -> Configure New Integration -> select Sellsy.

Authorize Sellsy (Client Credentials)

Go to Connections -> Add Test Connection -> Authorize, then enter your Sellsy Client Id and Secret shopper. Later, you’ll let your users do the same directly from your app.

Call the Sellsy API

Let’s make your first request to Sellsy (fetch a list of contacts). Replace the placeholders below with your Nango secret key, integration ID, and connection ID:

cURL
Node

curl -X GET "https://api.nango.dev/proxy/v2/contacts" \
  -H "Authorization: Bearer <NANGO-SECRET-KEY>" \
  -H "Provider-Config-Key: <INTEGRATION-ID>" \
  -H "Connection-Id: <CONNECTION-ID>" \
  -H "Accept: application/json"

Install Nango’s backend SDK: npm i @nangohq/node. Then run:

import { Nango } from '@nangohq/node';

const nango = new Nango({ secretKey: '<NANGO-SECRET-KEY>' });

// Fetch a list of contacts from Sellsy
const res = await nango.get({
  endpoint: '/v2/contacts',
  providerConfigKey: '<INTEGRATION-ID>',
  connectionId: '<CONNECTION-ID>'
});

console.log(res.data);

You can also fetch credentials dynamically via the Node SDK or API.

✅ You’re connected! Check the Logs tab in Nango to inspect requests.

Next step: Embed the auth flow in your app to let your users connect their Sellsy accounts.

Topic	Links
Authorization	Guide to connect to Sellsy (Client Credentials) using Connect UI
General	Sellsy Website
Developer	Sellsy API Documentation
	API Authentication
	Generate your client Credentials
	API Versioning
	Rate limiting
	API Access Types

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Sellsy (Client Credentials)