What Does a System Integration Cost?
By CodexierPublished 6 min read
Connect the webshop to Fortnox, the CRM to the booking system, the time reporting to payroll. The request sounds like one thing; the cost depends on how many distinct flows of data cross between the systems, what should happen when a flow fails, and who keeps it running when either system changes. This guide explains how we and most serious integrators price that work, so you can compare quotes on the same basis.
Counting the data flows
Write the flows down before asking anyone for a price. A typical webshop-to-accounting link is not one integration but four: orders become invoices, customers are created or matched, payments and payouts are reconciled, and product or stock changes go the other way. Each has its own mapping rules, edge cases such as refunds and partial deliveries, and failure modes. Two systems with one flow is a small job; two systems with six flows is a project.
Ready-made connectors vs custom
For common pairs, someone has already built a connector: Shopify to Fortnox, HubSpot to Google Calendar, Pipedrive to Mailchimp. Connectors and automation platforms such as Make or n8n cover standard flows at a monthly fee and little setup. Custom code is needed when the mapping has your business rules in it, when volumes are high, or when one of the systems has no public API.
| Situation | Usual approach | Cost driver |
|---|---|---|
| Standard pair, standard fields | Vendor connector or app | Monthly fee, a day of setup and testing |
| Standard pair, your own rules | Automation platform with custom logic | Rule design and testing of edge cases |
| Unusual pair or heavy volume | Custom integration service | Development, monitoring, upkeep |
| System without an API | File export and import, or a vendor upgrade first | Fragility; often better to change the system |
Ask which approach a quote assumes. Two quotes for the same request can differ several times over because one uses a connector and the other writes code.
Error handling and monitoring
The happy path is the cheap part. What costs is deciding, and then building, what happens when a customer has no organisation number, when Fortnox is down at two in the morning, when the same order arrives twice, or when a field that was always filled suddenly is empty. Every one of those becomes a support ticket if it is not designed.
- Retries with backoff for temporary failures, and a dead-letter queue for records that fail repeatedly, so nothing is silently dropped.
- A daily summary to a named person: how many records synced, how many failed and why, with a link to fix and resend.
- Idempotency: sending the same record twice must not create two invoices. This is the rule most home-built integrations miss.
Ongoing maintenance
API changes
Vendors deprecate versions and change fields with notice you may not read. Someone must track the changelogs of every connected system and test before deadlines.
Business changes
A new product type, a new VAT rule, a new payment provider. Each is a mapping change that should take an hour, if the integration was built to be changed.
Credential hygiene
API keys expire, staff leave, tokens get revoked. A maintenance routine renews them before the flow stops on a Friday evening.
Plan for a modest yearly maintenance budget from day one. An integration without an owner is the most common reason we are called in for an integration and automation optimisation: the original works, but years of unhandled changes have piled up.
Reusing work across integrations
The first integration builds things the second one inherits: a shared customer model, the mapping to your accounting fields, the monitoring and alerting, the credential handling, the way errors reach a human. Once those exist, connecting a third system is mostly mapping and testing. That is why a quote for the first system is high and the marginal cost falls after it.
- Decide which system is the master for each object: customers, products, orders. Every later integration relies on that decision.
- Build the first integration with a shared layer, not as a point-to-point script, even if it costs slightly more.
- Document the mappings and rules in plain language. This is the asset you reuse, and what a second integrator needs.
If you are unsure whether your current setup has that shared layer or is a pile of scripts, a CRM and integration audit maps it in a week; the fixed prices for the audit and the optimisation work are on the pricing page.
When you should not integrate yet
If the manual step takes an hour a week and the data is clean, a spreadsheet import may cost less than any integration over three years; do not automate a task that small. If one system is about to be replaced, integrate after the switch. And if the two systems disagree about what a customer is, fix the data model first, or the integration will copy the mess in both directions. A 15-minute call with your list of flows is enough to say which case you are in; for a worked example in one industry, see our note on CRM for estate agents.
Frequently asked questions
Why is the second integration cheaper than the first?
Because the first one builds the shared parts: the data model, the mapping to your accounting or CRM fields, the monitoring, the error handling and the credential routine. Later integrations reuse them and mostly need mapping and testing. That only holds if the first one was built as a shared layer rather than a one-off script.
Is an automation platform like Make or n8n enough?
For standard flows with modest volume, often yes, and it is the cheapest route. It becomes fragile when rules get complex, volumes grow or errors need careful handling, because retries, idempotency and monitoring become your problem. Many setups start there and move critical flows to custom code later.
What should an integration quote include?
The list of flows and their direction, the approach for each (connector, platform, custom), the error handling and monitoring included, the testing plan, documentation and the yearly maintenance offer. A quote that lists only the systems and a price is not comparable with anything.
Want a price based on your actual flows?
List the systems and what should move between them, in whatever form you have, and bring it to a short call. We count the flows with you, say which approach fits each, and give a fixed price for the work.
Book a free 15-minute call