What if my software has no API?

There are other routes: file export and import, processing order emails, or direct database access where the vendor allows it. In the first call we check what is possible.

Is custom software more expensive than an off-the-shelf product?

Up front, usually yes. It pays off when the product does not cover a key part of your work, or when the manual work around it happens every day. Often the best answer is an existing product plus a small integration.

What happens when a connected service changes?

Outside services change their APIs and terms. That is why integrations come with maintenance: I follow the changes and adjust the connection before it breaks.

Do you work with companies outside Croatia?

Yes, remotely. Invoices come from AV Solutions j.d.o.o., a Croatian company, and we can work in English.

Can I start with a small project?

Yes, and I recommend it. One integration or one automated report quickly shows whether it is worth going further.

Custom software

Custom software development

When off-the-shelf software does not fit the way you work, or two systems do not talk to each other, the answer is software written for your business. I work with companies in Croatia and across the EU.

When custom software makes sense

Off-the-shelf software is built for the average company. Trouble starts when yours is not average. Staff type the same data into two programs, someone copies orders into the accounting software every Friday, and a report is pieced together from three spreadsheets.

Custom software does not have to be a large system. Often it is a small program or a link between existing tools that removes one repetitive job.

What I do

API integration: connecting your website, app, accounting, payments and other services so data moves by itself.
Business process automation: reports, reminders, emails and data processing that are done by hand today.
Internal tools for staff, with roles and access rights.
Backends and APIs for mobile and web apps.
Server and cloud setup, with error tracking and backups.

Integrations from real projects

On Rent-a-Clean, card payments run through Stripe, and invoices are issued and fiscalised through the Croatian invoicing service Solo, with no manual copying. Emails go out through Resend and push notifications through Firebase Cloud Messaging. The web and mobile apps use the same API.

TacLink has an ASP.NET Core server that streams player positions live over SignalR, and organisers pay through Stripe Checkout. The API clients for web, iOS and Android are generated from one API description, so all three always agree.

A small-business example

A service company takes orders through a web form, then someone types them into a spreadsheet and issues the invoice from another program. A small integration can store the order in a database, send the client a confirmation and prepare the invoice. A daily chore becomes a quick check.

The same goes for rental owners who copy bookings from several channels by hand, or companies that build the same monthly report from several spreadsheets. When a task follows the same rule every time, a computer can do it.

Technologies

I pick what fits the problem and can be maintained for years. In my projects so far that means TypeScript, Next.js and Node.js, C# and ASP.NET Core, PostgreSQL with Prisma or Entity Framework Core, Swift and Kotlin for mobile apps, and Docker for server deployment. Hosting is on Vercel or a dedicated server, depending on the project.

How we work together

A free first call: which task repeats and how much time it takes.
A review of your existing systems and how they can be connected.
A proposal for the smallest solution that makes a real difference.
Build, testing on real data, and go-live.
Maintenance and changes when your business or a connected service changes.

Direct contact

The same person, Viktor Antunović, writes and maintains the software. No sales team and no messages passed through several people. I work in person with companies around Rijeka and Istria and remotely with clients elsewhere in Croatia and the EU.

Frequently asked questions

What if my software has no API?: There are other routes: file export and import, processing order emails, or direct database access where the vendor allows it. In the first call we check what is possible.
Is custom software more expensive than an off-the-shelf product?: Up front, usually yes. It pays off when the product does not cover a key part of your work, or when the manual work around it happens every day. Often the best answer is an existing product plus a small integration.
What happens when a connected service changes?: Outside services change their APIs and terms. That is why integrations come with maintenance: I follow the changes and adjust the connection before it breaks.
Do you work with companies outside Croatia?: Yes, remotely. Invoices come from AV Solutions j.d.o.o., a Croatian company, and we can work in English.
Can I start with a small project?: Yes, and I recommend it. One integration or one automated report quickly shows whether it is worth going further.