What IustumOS is

IustumOS is a software practice in Phnom Penh, run by Romulus, working with organisations across Cambodia.

The person who takes your first message is the person who writes the specification and builds the system. Nothing is handed down a chain, which is the reason a detail you mention once in passing tends to survive into the software rather than getting lost between a sales conversation and a development queue.

Work is taken on deliberately rather than continuously, so a project gets attention while it is live instead of a place in a backlog. If the timing does not work, you will be told at the start rather than halfway through.

This started with a payroll spreadsheet at a family business.

The rules were not complicated. They were simply written down in one place and calculated in another, with a person in between doing the connecting from memory, every month, under time pressure. Nobody was careless. The structure just made a small mistake inevitable eventually, and payroll is a bad place for eventually.

What surprised me was that buying software did not fix it. The products available were built somewhere else, for somewhere else, and they treated Cambodian regulation as a setting to be filled in rather than a structure to be enforced. You could bend one into approximately the right shape. Approximately is exactly the wrong standard when the number is somebody's wages.

So the idea here is narrow. Read the instrument. Turn each rule into something the software enforces rather than something a person remembers. Keep every figure traceable back to the document it came from. When the regulation changes, change the parameter instead of rewriting the program.

I would rather tell you a project is a poor fit than take it and find out together. That is not modesty. Software that enforces rules is a bad place to be learning what the rules are, so if I do not understand your situation well enough to be useful, saying so early costs you a conversation instead of a quarter.

Everything I build is handed over with its source, its database migrations and documentation good enough for somebody else to pick up. You are not meant to be locked in. If you outgrow me, you should be able to leave with the thing you paid for and no hard feelings.

There is one habit underneath all of this, and it is the thing worth judging the work by.

Every rule the software enforces is checked against the document it came from, not against what anyone remembers about it. Regulation is easy to be approximately right about. Approximately right is how a payroll run quietly underpays somebody for a year, and it is why the citations on this site carry the date they were last verified rather than asking you to take them on trust.

The systems on the work page are running in production, used by real people, handling real money. Each one is written up with how it was built and what was difficult about it, including the parts that were harder than expected.