Connect Fortnox to HubSpot — keep customer data and deals in sync
Do you sell in HubSpot and invoice in Fortnox? Then your customer data lives in two places that easily drift apart. An integration keeps contacts, organisations and deals in sync, so that a won deal in HubSpot automatically becomes a customer and invoice data in Fortnox — and a paid invoice updates the deal back again. You change neither your CRM nor your accounting; you get them to talk to each other.
Quick overview
In short: Connecting Fortnox to HubSpot means that contacts, organisations and deals are synced between the systems — a won deal creates a customer and invoice data in Fortnox, and a paid invoice updates the deal in HubSpot, without duplicated work and without duplicates.
How to get started:
- Decide which event should start the flow, e.g. "deal won in HubSpot → customer + invoice data in Fortnox".
- Map the fields: company registration number, contact details, amount and the deal name should land correctly in Fortnox.
- Build the connection (e.g. in n8n, Make or Zapier), test it with a few real deals and reconcile in both directions.
GDPR: contact and organisation data are personal data — map what flows, sign a data processing agreement and choose EU or self-hosting when you want the data to stay in Sweden.
What a Fortnox–HubSpot integration solves
Without an integration, your customer data lives twice. The salesperson has it in HubSpot, finance has it in Fortnox, and the two versions drift apart. Someone enters a new customer by hand in Fortnox when the deal is won, address changes reach only one system, and when the invoice is paid the salesperson doesn't know. That creates duplicated work, duplicates and internal misunderstandings.
Both HubSpot and Fortnox have open APIs, and HubSpot also sends webhooks and can trigger workflows — signals fired the moment a deal changes stage or closes. That makes the connection rewarding to build: a won deal in the CRM triggers the right action in accounting, and information can flow back so the sales team sees the status.
What actually gets synced
Plan the integration by listing which events should trigger which actions — and in which direction. Some flows go from HubSpot to Fortnox, others back again. Here are the most common ones for Swedish B2B companies:
| Event | Action | Things to consider |
|---|---|---|
| Deal won in HubSpot | Customer + invoice data created in Fortnox | Match on reg. number so no duplicates arise |
| New contact/organisation in HubSpot | Customer record created/updated in Fortnox | Decide which system owns address details |
| Updated customer detail | Synced to the corresponding record | Avoid both overwriting each other at once |
| Paid invoice in Fortnox | Deal updated + notification in HubSpot | Notification to the right salesperson via Slack/Teams |
| Overdue invoice | Task/notification to the account owner | Good basis for upselling and follow-up |
You don't need to build everything at once. Start with what steals the most time — usually won deal→customer→invoice data — and add two-way sync and notifications as you go. You'll find more examples among our solutions.
From won deal to invoice data
The core of the integration is the chain won deal → customer → invoice data. When a deal is closed as won in HubSpot, you want the customer to exist in Fortnox (or be created if new) and a correct set of invoice data to be generated from the deal's value and line items. That way the salesperson doesn't have to email details over to finance, and invoicing gets going without delay.
What determines whether the connection is stable is the field mapping — that every piece of information lands correctly:
- Customer matching on the company registration number so existing customers aren't duplicated.
- The right contact person, invoice address and reference from the deal.
- The deal's amount and line items mapped to the right articles and VAT rate in Fortnox.
- A shared ID or reference so the deal and invoice can be linked together in both directions.
Two-way sync and avoiding duplicates
The most common pitfall is duplicates. If the same customer can be created in both HubSpot and Fortnox without a link, you'll soon have two truths. The solution is to always match on a unique key — almost always the company registration number — and to decide which system "owns" each piece of information. Let HubSpot own the contact information and Fortnox own the invoice history, for example, so the systems complement each other rather than overwrite.
The other direction is at least as valuable: when an invoice is paid in Fortnox, the deal in HubSpot can be updated and a notification sent to the right salesperson. The sales team then sees that the customer is over the line without having to ask finance, and an overdue invoice can become a follow-up task. If you want to see the full picture of what can be automated, read our guide on how to automate the business.
Ready-made connector, your own integration, or help?
There are ready-made connectors and middleware services that sync HubSpot and Fortnox, and they can be enough for a simple need. But as soon as you have specific requirements — Swedish VAT handling, your own deal stages, two-way sync or matching on the company registration number — a bespoke connection is often both more accurate and cheaper to run in the long term.
A good rule of thumb: try a ready-made connector to get going, but build your own integration when the flow has to carry real work and the customer data must be correct in both systems. At Nuvid we build on top of the systems you already use — you change neither HubSpot nor Fortnox, we get them to work together and keep the flow maintainable over time.
GDPR and keeping the data in Sweden
Contacts, organisations and deals contain personal data: names, roles, email and purchase history. When they flow between HubSpot and Fortnox, GDPR applies. HubSpot operates partly outside the EU, which places requirements on the legal basis for transfer. If you build the connection yourself, you can control where the intermediate layer runs — with self-hosting in the EU or Sweden, that part of the data stays here.
- Map which personal data flows between HubSpot and Fortnox and where it goes.
- Sign a data processing agreement with the providers that process the data.
- Choose an integration platform that can run in the EU or be self-hosted when the data is sensitive.
- Sync only the information the systems actually need — less data, less risk.
Getting started — a small first flow
Start small and focused. Take the flow that steals the most time — almost always won deal→customer→invoice data — and get just that working reliably. Once it saves time and the customer data is correct, you build on with two-way sync and notifications.
- Write down how you currently transfer a won deal from HubSpot to Fortnox, step by step.
- Decide which event should start the flow (e.g. a deal marked as won).
- Build the connection and test with a few real deals before going live.
- Reconcile in both directions and add the next flow.
Want help setting it up right from the start? Get in touch and we'll look at your HubSpot and Fortnox setup together. If you want to understand the whole ecosystem first, read our pillar guide on system integration for small businesses.
Want to see how this looks in practice? Explore our solutions, see case studies and platforms we've built, or get three free suggestions.