The old system still runs. Nobody dares touch it.

Private Sub btnSave_Click()
  If IsNull(Me.Paino) Then
    Exit Sub
  End If
  DoCmd.RunSQL "INSERT INTO" _
    & " Kuormat (Auto, Paino)" _
    & " VALUES (..)"
  Me.Requery
End Sub

async Task SaveAsync(Load l)
{
  Validate(l);
  await db.Loads.AddAsync(l);
  await db.SaveChangesAsync();
  await grid.RefreshAsync();
}

The application only runs on one old machine

A quoting tool or an invoicing helper runs on the Windows 7 box in the corner. Nobody knows whether it will start after an update.

The original developer is gone

One person built it and has since moved on or retired. The source code may exist, but the development tools are no longer available anywhere.

Several old applications, no overall picture

A dozen custom tools are blocking a server upgrade or an ERP change. Which ones to keep, which to replace, which to retire?

You do not need to specify anything up front

You show me how the work is done. I dig the rules out of the code, the database and the running application and bring them to you for confirmation.

You see a working result before committing to more

First a fixed-price assessment, then one workflow on the new platform running side by side with the old one. Only then do we decide whether to continue, and at what price.

The new system produces the same results as the old one, and that is verified

I run the same data through both and compare the results. You see the differences before go-live, not after.

Everything stays with you at every stage

I produce code, not paperwork: the source code is yours at every stage. You can stop after any stage or continue with someone else.

Initial conversation

You tell me what the application does and what worries you. I tell you whether it is worth proceeding and what the assessment costs.

Start-up assessment

Application running in a controlled environment, dependencies mapped, rules uncovered and brought to you to confirm. No pile of reports.

One workflow on the new platform

The most important workflow running alongside the old one on the same data. You see the comparison before the next decision.

The rest, and handover

Each part with its own price and its own acceptance. At the end: a working application, its source code and a rollback plan. After that the new application can be developed further like any other.

AI does much of the work, not the decisions

I use AI for reading code, implementation and verification. The measure of correctness is still the old application's actual output and your confirmation.

Where your code and data are processed

Agreed in writing before we start. I do not send production data to AI models; testing uses anonymised data. Fully closed processing is also possible.

If a one-person supplier is unavailable

Source code is handed over at the end of every stage. The technologies chosen are kept as mainstream as possible, so anyone who knows them can develop the application further.

Make your AI-built app production-ready

The app was built with Lovable, Bolt, Cursor or ChatGPT and is already in use, but security, data and maintenance worry you. I review it at a fixed price and fix the most dangerous things first, without throwing away what has been built.

Who does the work

Jussi Koistinen. Over 20 years in software, from Delphi and VB to .NET, React, Node.js and mobile, plus large databases from Oracle to SQL Server and PostgreSQL. A large part of my career has gone into understanding and renewing systems built by others. Jkodez Innovations Oy is a one-person company based near Kuopio, Finland, working with clients across the country.