What you need to know, with the source attached.
Twenty articles about what comes after your prototype and what belongs with a sole proprietorship (eenmanszaak). Each article opens with the answer, names its sources and carries the date on which it was checked. Free, without an account. The tax explanation on this page follows Dutch law and is written for Dutch sole proprietorships (eenmanszaak).
Not tax advice; you file yourself. Read the disclaimer
From prototype to live
What sits between a working prototype and a project at your own address.
The cliff: why so many AI prototypes never go live
Your prototype works and then it stalls. This article explains what the cliff between prototype and live is, where it sits and how you get across.
Connecting a domain to your AI app, in plain language
Connecting a domain is filling in two lines at your registrar and waiting. What an A record and a CNAME are, what your host gives and why it takes time.
What to do with your database before you go live
A prototype database is meant for testing, not for keeping. What changes once real people enter data, and the one backup that counts.
Starting your business
The moment a project becomes a sole proprietorship (eenmanszaak), and what you arrange then.
When you have to register with KVK
Register once you supply independently and regularly to others than family, for more than your costs. The criteria and what comes after.
Freelancing alongside a job: what the tax authority, your employer and you need to know
What you earn alongside your job adds up with your salary and is taxed where your salary stops. What the tax authority, your employer and you need to know.
What your bookkeeping must legally contain, and how long you keep it
You keep your bookkeeping for seven years, ten for real estate. What it must contain at minimum, when the period starts and in what form you may keep it.
VAT
Filing a return, the small businesses scheme and what you set aside.
Filing a VAT return for the first time, box by box
Your first VAT return is four numbers: turnover, the VAT on it, the VAT you paid yourself and the difference. Box by box, with the dates of 2026.
The kleineondernemersregeling (KOR): when it fits and when it does not
With the Dutch KOR you charge no VAT and file no VAT return, up to €20,000 turnover a year. When that pays, when not, and what happens as you grow.
How much do you set aside for tax
Part of every euro of turnover was never yours. How your turnover splits into three streams, and why a fixed percentage does not work.
Income tax
The hours criterion and the deductions, also when you have a job alongside.
The urencriterium of 1,225 hours: do you reach it, and how do you prove it
The Dutch urencriterium is at least 1,225 hours a year on your business, and more than on other work. Which hours count and how you prove it.
The zelfstandigenaftrek alongside a job: why it usually does not work
Alongside a 32-hour job the Dutch urencriterium is almost out of reach, and the deduction is €1,200 in 2026. The calculation and what you do get.
Invoices and payment
What an invoice must contain and what you may do when a customer does not pay.
What an invoice must legally contain
An invoice has eleven mandatory parts, from your VAT identification number to the delivery date. Which ones, why, and what a small invoice may leave out.
Payment terms, default and what you may do when a client does not pay
Without an agreement, the payment term between businesses is 30 days, then commercial interest runs. What default is, what to charge and in what order.
The fourteen-day letter: how to send it, and what goes wrong if you get it wrong
A consumer who pays late first gets fourteen days to pay without extra costs. What the letter must say and when that term starts.
Costs and depreciation
When a purchase is a business asset and how you depreciate it.
AI and tools
Tokens, version control and the terms you meet when you build with AI.
What is vibe coding, and what it is not
Vibe coding is building by describing what you want and accepting what the AI makes. What the term means, where it comes from and where it stops.
What does a million tokens actually cost
A token is a piece of text of about four characters, and an AI model charges per million. What that costs for a chat, a document and a day of building.
Git and GitHub for people who are not developers
Git keeps every version of your project, GitHub keeps them in a place that is yours. Five terms in plain language, and why you need them.
Security
What you check before a stranger opens your project.
The security checklist before you go live
Seven checks before a stranger opens your project: access, what is in the code, what a visitor can enter and what happens when things go wrong.
Prompt injection: how a document or website can take over your AI agent
An AI agent that reads a web page or document can follow instructions in that text as if you gave them. What it is, how to spot it and what you do.
This is general information, not tax or legal advice. basestep calculates and explains; you file yourself. If you are unsure about your situation, consult an adviser.
From first prompt to tax return.
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