What is an API integration?

API stands for Application Programming Interface. An API integration is a digital connection that allows two software systems to automatically exchange data, without anyone having to retype anything. You can think of it as a fixed, agreed-upon gateway through which systems send information and commands to each other.

More and more companies work with separate software packages: an accounting program, a CRM, a webshop, an inventory system. If these don't communicate, you end up entering the same data in multiple places. An API integration solves that. In this blog, we explain exactly what an API integration is, how it works, what the benefits are, and when you should consider having a custom API integration built.

Author: Jordi van den Broek

Published: 12 October, 2026

How does an API integration work? A simple explanation

‘API integration’ is a technical, abstract concept. That's why we explain it with a classic analogy: you give your order to the waiter, the waiter brings it to the kitchen, and returns with your meal. You don't have to go into the kitchen yourself. An API works just like that.

For example, a webshop might send a request to a CRM, such as: 'Give me the customer details’ or 'create an invoice'. The API passes on the request and returns the answer. These requests go through fixed points called endpoints. Each ‘type of data’ or specific task has its own endpoint. For example, there is one endpoint for customer data and another for invoices. One system sends data to it, the other retrieves it. Because these points are fixed, the exchange remains fast and organized.

A concrete example of an API integration

Imagine you run a wholesale business with a webshop, an inventory system, and an accounting package. Without integration, someone has to manually enter every order into the administration and update the inventory by hand. With dozens of orders a day, that takes a lot of time and mistakes can easily creep in.

With an API integration, this all happens automatically. As soon as a customer places an order on your website, the webshop sends the order through the API. The inventory is updated instantly, and the invoice is automatically entered into your accounting system with the correct VAT. Everyone works with the same, up-to-date information.

Important: an integration doesn't just let systems "talk" to each other. Two systems often speak very different languages — different data formats, different field names, different ways of logging in. A good integration translates that data, converts it into the right format, and ensures everything stays in sync at the right time. That translation and synchronization is exactly what it's all about in practice.

Data integration or API integration: what's the difference?

‘Data integration’ and ‘API integration’ are terms that are often used interchangeably. Both refer to making systems work together, but they aren't exactly the same. Data integration is a broader concept: any way in which systems share data falls under it. An API integration is a specific, modern form of data integration.

Datakoppeling: verzamelnaam voor elke verbinding waarmee systemen data uitwisselen, bijvoorbeeld via een API, webhooks of bestanden zoals Excel of CSV uit te wisselen

API koppeling: een datakoppeling via een API, waarbij systemen live en gestructureerd gegevens uitwisselen.

Which API integrations does Dolphiq build?

For ANWB, we built a direct API integration with a data warehouse, making that data usable in an online application. The data warehouse had a fully custom API, and we tailored the integration entirely to it.

For another client, we created an API integration with the open data portal of the Dutch government. The business information system we previously built now automatically retrieves data from that portal. We then analyze the retrieved data with AI, using the APIs of the OpenAI Platform.

These are just two examples—almost every project we work on uses data or API integrations.

The benefits of an API integration

Less manual work

Data flows automatically between systems, so no one needs to enter it manually anymore.

Fewer errors

Without manual entry, you avoid typos and duplicate data.

Always up-to-date data

A change in one system is instantly visible in the other, in real time.

Time for what matters

Employees can focus on customers and growth instead of repetitive data entry.

Scalable and expandable

Whether it's 50 or 50,000 transactions, an integration processes them at the same speed, and you can easily expand it later.

When do you need an API integration?

An API integration becomes interesting as soon as your systems no longer understand each other. Are you entering the same data over and over in different packages? Are inventory, orders, or customer data not in sync? Or do you want an API integration with your website so orders automatically end up in your back office? These are clear signs that manual work is costing you time and money, and that an integration will quickly pay for itself.

An API integration is especially valuable for organizations that use multiple systems and want those systems to work together smarter. Over the years, separate programs are often added that barely communicate: a CRM for customers, an accounting package for invoices, a webshop for orders, and a planning tool for the calendar. Each program does its job well, but doesn't exchange data with the others. That's exactly where you can gain efficiency. For example, a new customer in your CRM can automatically appear in your accounting, or an order from your webshop can instantly create a task in your planning tool. By connecting these systems, you let them do the work instead of your colleagues.

So far, we've talked about your software retrieving data from another system. But it can also work the other way around: other parties might want to access data from your software. Think of a supplier who wants to automatically see your current inventory, or a customer who wants to view your data in their own dashboard. In that case, you're the one providing an API. You have a custom API developed, a secure and dedicated gateway through which others can request exactly the data you choose to share.

When should you choose a standard integration or a custom integration?

For popular combinations, ready-made integrations are available. Tools like Zapier easily connect hundreds of well-known systems, n8n does the same as an open-source option you can host yourself, and for larger organizations there are more robust integration platforms like Workato or MuleSoft. If such a standard integration fits your process, that's often the smartest and most cost-effective starting point. As we always say: start standard, unless there's a good reason not to.

That reason appears as soon as you hit the limits of a ready-made tool. Custom solutions typically pay off when:

No API integration exists

Some systems don't (yet) have a usable API. Think of older or industry-specific software. In that case, you need a custom API integration.

Your process is different

As soon as validations, calculations, or exceptions come into play, a ready-made integration falls short. A custom integration follows your way of working.

Volumes are growing

Standard integrations charge per transaction. With large volumes, costs can rise quickly. A custom integration handles those volumes without the costs increasing.

Keep control of your data

When personal data passes through the integration, privacy or GDPR regulations often mean it can't go through a foreign third party. A custom integration keeps your data where you want it.

Reliability & ownership

An integration that stops working doesn't notify you, and you usually only notice when something goes wrong. A custom integration gives you proper error handling and insight into what's happening.

The benefits of having a custom API integration built:

Perfect fit: a custom integration matches your way of working exactly.
Easy to expand: you can easily add new systems or features later on.
Secure and manageable: the integration meets your requirements for security and management.
Ready for AI: AI applications only become valuable when they can access your data via APIs, such as an assistant that answers customer questions based on your current order data.

Ready to connect your systems?

Systems that don't communicate cost time, money, and lead to mistakes. A good API integration eliminates those issues and gives you consistent, up-to-date information everywhere. Whether you need an existing integration or want a custom API integration built, Dolphiq will help you from the first idea to a working solution.

Curious what a custom API integration could mean for your organization? Get in touch and discuss the possibilities with no obligation.