For most Nordic small and mid-sized companies the answer is neither pure custom nor pure off-the-shelf. Buy the system of record, such as Fortnox, Visma or Business Central for accounting and ERP, and HubSpot or similar for CRM. Build custom software only for the workflow that sets you apart or that the standard system handles badly, and connect it through the API. A focused custom system built by our custom software development team typically costs €30,000–150,000, with a fixed price after discovery. This guide is for CEOs, CFOs and IT managers deciding whether to buy, extend or build.
Three terms first. Off-the-shelf software is a standard product you license, usually as a subscription (SaaS). Custom software is built for your workflow and owned by you. A system of record is the system that holds the official version of a piece of data, such as your ledger or your customer register.
When should you buy off-the-shelf software?
Buy when the process is the same in every company and the rules change without you:
- Bookkeeping, VAT, payroll and annual accounts. Fortnox, Visma and Business Central follow Swedish rules and update them when the rules change. You don’t want to own that code.
- CRM, email marketing, helpdesk and HR. These are mature categories with good products at a reasonable price per user.
- Anything where the fastest route to value matters more than fit. A SaaS can be running in days; a custom system needs weeks.
The test is simple: if you can adapt your process to the product without losing anything your customers notice, buy the product.
When should you extend the standard system instead?
Many gaps are small: one approval step, a report, a field the product doesn’t have, data that must flow from one system to another. Before building anything, check what the vendor supports. Business Central has extensions, Fortnox and Visma have APIs and integration partners, and HubSpot has custom objects and workflows.
Extending is the cheapest route when the gap is small and the vendor supports it. The risk is customizing a standard system until every upgrade breaks something. If your list of changes keeps growing, that is a sign the workflow belongs in its own application.
When does custom software pay off?
Custom software pays off when one of these is true:
- The workflow is how you win business: quoting, planning, pricing, field reporting or a customer experience your competitors can’t copy by buying the same tool.
- Staff copy data between two or three systems every day, or keep the real process in spreadsheets next to the system.
- You have many occasional users, such as field staff, partners or customers, and per-user licenses scale badly.
- The standard product’s data model or permissions don’t match how you work, and you hit the limits of tools like HubSpot or Monday.com.
Construction is a typical example. Accounting fits Fortnox well, but tenders, project phases, site reporting and hours don’t fit a generic ERP. The common answer is a construction ERP built around how projects actually run, which sends invoices and time data to the accounting system.
Decision table: buy, extend or build?
| Your situation | Best option | Why |
|---|---|---|
| Bookkeeping, VAT, payroll | Buy (Fortnox, Visma, Business Central) | Swedish rules change; the vendor maintains them |
| A standard sales process | Buy a CRM | Mature products, low cost per user |
| The standard system covers everything except one or two steps | Extend it, or build a small add-on through the API | Much cheaper than replacing the core |
| Staff re-enter data between systems every day | Custom integration or add-on | Double entry costs hours and creates errors |
| The workflow is your competitive edge | Build custom, keep accounting standard | You own the logic and can change it |
| Many occasional users outside the office | Custom portal or app | Per-user licensing scales badly |
| Strict requirements on where data lives and who sees it | Custom on EU hosting, or self-hosted | You control the data and the access rules |
What does each option cost over five years?
Compare five-year cost, not the first invoice. Here is an illustrative example: a company with 25 field users that needs quoting, work orders and time reporting, with invoices ending up in Fortnox. All figures are assumptions for the example, not quotes.
| Cost item (5 years) | Industry SaaS | Custom app connected to Fortnox |
|---|---|---|
| Setup or build | €5,000 onboarding | €60,000 fixed-price build |
| Subscriptions | €60,000 (25 users × €40/month) | None |
| Fortnox integration | €0 if built in, otherwise €10,000–20,000 | Included in the build |
| Hosting and services | Included | €15,000 (about €250/month) |
| Maintenance and small changes | Included | €50,000 (an assumed €10,000/year) |
| Price increases | Set by the vendor | In your control |
| Total | €65,000–85,000 | €125,000 |
On these numbers the SaaS wins clearly, and if it fits your process you should buy it. The calculation changes when the product doesn’t fit. If each of the 25 users loses 15 minutes a day to double entry or workarounds, that is around 1,400 hours a year. At an internal cost of €35 an hour that is roughly €48,000 a year, or €240,000 over five years, which is more than the custom build.
Maintenance is real money either way. If the system is business-critical and you want us to keep it patched and monitored, Care Lite costs €4,200 a month. A small add-on may only need occasional work from your own developer.
What mistakes should you avoid?
- Customizing a standard system so heavily that upgrades become projects.
- Building commodity features, such as login, invoicing or bookkeeping, that you could buy.
- Launching custom software without an owner and a maintenance budget.
- Signing a SaaS contract without checking how you get your data out, and in what format.
- Deciding on license price alone, without counting integration work and staff time.
Revisit the decision every year or two. Standard products add features and APIs improve, so the line between buy and build moves.
What to do next
Write down the workflow you are unsure about: who does what, in which systems, and where the spreadsheets are. If buying or extending covers it, you have your answer. If not, our discovery maps the workflow and the integrations and ends with a fixed price for the custom software that fills the gap, typically within €30,000–150,000. For the full cost picture, see how much custom software development costs.
