Middleware and API integration development

Your systems talk to each other, and you find out when that goes wrong

Your CRM knows something your accounting doesn't, and someone retypes it. We build the middleware that connects your systems: through an API where there is one, through an adapter where there isn't. With logging, retries and an alert when something gets stuck, so an integration never loses data without anyone noticing. Senior developers at Hofplein in Rotterdam.

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Integrations that lose nothing

Every step logs what it did. When an external API goes down for a while, the message waits in a queue and the integration tries again.

Even without a proper API

An old system with only an export, a database or an FTP folder gets an adapter, so everything else can talk to it.

You see what happens

An overview of what came through and what didn't, and an alert with the reason attached. You hear it from the integration before a customer notices.

Yours, also after delivery

The code lives in your repository and runs on your infrastructure. Another developer can read it, change it and take it over.

Our Skills and Technologies

API Integration
Webhook Management
GraphQL
n8n
Make.com
Node.js
TypeScript
Python
FastAPI
PostgreSQL
Docker

What middleware does

Middleware is the software between your systems. It fetches data from one system, converts it into what the other expects, and delivers it. A new order in your webshop becomes an invoice in your accounting, a lead in HubSpot gets company details from the Dutch Chamber of Commerce, and a change in your ERP shows up in your customer portal within a minute.

An integration that works is the easy part. The work is in what happens when it goes wrong: an API that is down for an hour, a webhook that arrives twice, a field the vendor renames without warning. That is what we build the middleware around.

Sound familiar?

  • Someone retypes data from one system into another, every day, and gets it wrong now and then.
  • You have a Zapier, Make or n8n flow that mostly works, and you only find out it stopped when a customer calls.
  • Your vendor has an API, and nobody in-house knows how to connect to it reliably.
  • An old system has no API and still needs to talk to the rest.
  • Duplicate records show up, or a few go missing, and nobody can say where.

What we connect

Your business systems, connected

The integrations that hold the most manual work.

A CRM like HubSpot or Salesforce to your invoicing and support
ERP and inventory to your webshop
Accounting like Exact, Moneybird or Twinfield to your orders
Payments through Stripe or Mollie to your own records

Old systems without a proper API

The system that has run for years and that nobody dares to replace.

An adapter around a database or export, with a modern API in front of it
CSV, XML or FTP exchange that runs automatically and gets checked
A layer that shields the old system, so you can replace it later without reconnecting everything

The reliability underneath

What decides whether an integration is still right a year from now.

A queue and retries, so an outage at a vendor costs no data
A duplicate check, so a webhook that arrives twice creates one record
Signature checks on webhooks, so only the sender can trigger them
Logging per step and an alert with the reason when something gets stuck

What that looked like at a mobility scale-up

A B2B scale-up in the mobility market had a Make flow that enriched new HubSpot leads with data from the Chamber of Commerce API. It worked, until a timeout at the Chamber of Commerce made a lead disappear, a HubSpot rate limit dropped an hour of leads, and a duplicate webhook created the same lead twice.

We didn’t throw the flow away. Every step now logs to a central database, a failed enrichment flags the lead for manual completion and lets the rest of the flow continue, and a check at the start stops duplicate messages. Read the full case.

Where this sits next to our other services

If the integration needs AI, an agent that reads, decides or writes in your systems, AI automation is the page for that. If you need a whole new system and the integration is one part of it, start with custom software development. This page is about the layer in between: your systems already exist, and they need to talk to each other.

What does an integration cost?

An integration between two systems with a good API is a well-defined job. What sets the price is how many systems take part, how good their APIs are, and how much goes wrong when a message gets lost. An old system without an API costs more, because it needs an adapter first.

We agree on a fixed price up front, after we have looked at your systems in the free consultation. You get a range with the assumptions attached, so you can see where it could come out higher or lower.

How it goes from your first message

1

Getting to know each other, 1.5 hours

You tell us which systems you use and what gets moved between them by hand. We look at their APIs and what is missing.

2

The data flow on paper

Which system is the source of which data, what happens on a conflict, and what should happen when a message doesn't arrive. With a fixed price and a date attached.

3

Building and testing with real data

We build the integration in your environment and test it on real records, including the edge cases: outages, duplicate messages, missing fields.

4

Going live with visibility

Logging, monitoring and an alert when something gets stuck. After that you can carry on yourself, or we keep the integration running for you.

Frequently Asked Questions

What is middleware?

Middleware is software that sits between two or more systems and lets them talk to each other. It fetches data from one system, converts it into the format the other expects, and delivers it. Think of an order from your webshop that automatically becomes an invoice in your accounting, or a lead from your CRM that gets completed with company data from a public register. Good middleware also keeps track of what happened, retries when a system is briefly unreachable, and reports it when that fails.

What is the difference between an API integration and middleware?

An API integration is the connection to one system through the API that system offers. Middleware is the layer that brings several of those connections together and handles the logic between them: which system leads, what happens on a conflict, and what happens to a message that doesn't arrive. With two systems that connect directly, the difference is small. As soon as three or more take part, or one of them has no good API, you need middleware.

Can you connect a system that has no API?

Yes. A system without an API almost always has another way out: a database, a CSV or XML export, an FTP folder, or a screen you can read. We build an adapter around it that behaves like an ordinary API to everything else. The benefit is that you can replace the old system later without rebuilding every other integration.

Do we have to throw away our Zapier, Make or n8n flow?

Usually not. A flow that runs proves the process is right. Often it is enough to add logging, error handling and a duplicate check, as we did for a B2B scale-up with a Make flow on HubSpot. Sometimes part of the flow is better off as its own code, for example when it runs into platform limits or when sensitive data passes through it. We decide that step by step.

What does it cost to have an integration built?

That depends on how many systems take part, how good their APIs are, and how bad it is when a message gets lost. An integration between two systems with a good API is a well-defined job. An old system without an API costs more, because it needs an adapter first. We agree on a fixed price up front, after we have looked at your systems in the free consultation.

Who maintains the integration after delivery?

That's your choice. The code lives in your repository and runs on infrastructure you own, with documentation of what runs and how to restart it. Your own developer or another party can take it over. If you want us to keep it running and update it when a vendor changes its API, we can do that too.

Do you work for companies outside Rotterdam?

Yes. We are at Hofplein in Rotterdam and happy to visit companies in the region, but we do most integration work remotely, for clients across the Netherlands. For the first conversation you can come to the studio or meet online.

Meet our experts in middleware and integrations

Our team, with the people who work on this most at the top.

More about us

What we also help with

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Have your app built

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Hire a Fractional CTO

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Rapid Prototyping & MVP Development

Fast development of working prototypes and MVPs to validate your ideas and demonstrate to investors. From concept to clickable prototype in weeks, not months.

Systems that need to talk to each other?

Tell us which systems you use and what gets moved between them by hand today. In the first conversation we tell you what an integration would save and what it costs.

hello@010codingcollective.com
+31 6 1353 2728
Free consultation at 010 Coding Collective
free

Free consultation

In an hour and a half we walk through your systems and your data flow, and tell you which integration saves the most manual work. Honest advice, no sales pitch.

1.5 hours with senior developer(s)
We look at your systems and their APIs
Written summary afterwards
An estimate of time and cost