Ask a question. Get the paperwork done.
Rentstag keeps everything about your rentals in one place — contracts, bills, meter readings, payments. You ask in normal words and get a straight answer, or the finished document, in seconds.
Free for 14 days on one building. No card, nothing to install.
Unpaid rent — September.xlsx
Yearly statement 2025 — all 42 flats.pdf
Rent increase letters — ready to send.zip
Any kind of building
New block, old block, or the one with scaffolding on it.
Shops on the ground floor, flats above, three different contracts per staircase and a heating bill nobody wants to split. That's the normal case, and it's what this was built for.
How it works
Three steps. That's the whole thing.
Contracts, bills from suppliers, bank statements, photos of meters. Email them over or drop them in. We put it all in one place so nothing lives in a folder on somebody's laptop any more.
Not the AI — a proper calculator, using the rules of the country the building is in. That's why the number comes out the same every single time, and why you can always show exactly where it came from.
The way you'd ask a colleague. You get the answer back, and if the answer is a document — a statement, a letter, a list — it comes back finished and ready to send.
What you can ask
If you can say it, you can ask it.
These are real questions people type. There is no list of commands to learn and no menu to find.
Who owes me money?Names, amounts, how late
Which flats are empty?And when the next one frees up
Did that payment come in?Even without a reference number
Can I put the rent up?On which contracts, and by how much
What did we spend on heating?Per building, per year, per flat
When does this contract end?And when you have to give notice
Send the tenant their statement.Written, ready, waiting for your OK
How much did I make last year?Per building or across the lot
The yearly bill split
The worst week of your year, done in four days
Once a year you have to work out what each tenant actually owes for heating, water, cleaning and the rest. It means going through every supplier bill, every meter reading and every contract, and there is a legal deadline.
You hand us the pile. You get back one statement per flat, in the tenant's own language, plus a summary for the whole building. We do it the way each country requires.
Try it on one building
Who owes you money
Find out in March, not in December
Your bank statement comes in and Rentstag matches the payments to the right tenants by itself — 97 out of 100 of them, including the ones with no reference number where you would normally hunt by amount and date.
The few it can't match come back with a plain reason: no reference, wrong amount, unknown sender. So a tenant who stops paying shows up straight away instead of surfacing at year end.
See it on one monthWhere you use it
In ChatGPT, the way you already use it
There's no new program to install and no dashboard to learn. You connect Rentstag to ChatGPT or Claude once — it takes about a minute, like linking any other app — and from then on you just ask, in the window you already have open.
Questions get answered straight away. Anything that would actually send something to a tenant, a bank or an office stops and waits for you to say yes. Nothing goes out behind your back.
Connect it and tryRaising the rent
Who you can raise, and by exactly how much
Some contracts let you raise the rent with inflation, some cap it, some don't allow it at all. Rentstag has read all of them and knows which is which, so you're not going through a folder of PDFs in December.
Ask, and you get the new figure per flat, what it adds up to, and the letters to tenants written and ready. They only go out when you say so.
Work out next JanuaryYour data
It stays yours, and you can take it with you
Rentstag LLC is registered in Jackson, Wyoming, in the United States, and our European office is in Amsterdam. European files stay on European servers in Frankfurt. You choose Europe or the US when you sign up, and we sign the European data agreement before anything is loaded.
Only your team can see your files, and you decide who gets which buildings. If you ever want to leave, you download the lot and go — no fee, no waiting period, no phone call where somebody tries to talk you out of it.
Ask us the details
Why us
Four reasons, in plain words
Ask a chatbot to add up a column and it might give you a slightly different answer next time. Here the AI only understands the question — a calculator works out the number, the same way every time, and you can always see which bills and which rule it used.
No program to install, no training day, no extra password. If someone on your team can use ChatGPT, they can use this. The people who hate new systems never have to open one.
Splitting the yearly bill is done differently in the Netherlands than in Germany or Poland, and the deadlines are different too. That's built in, not bolted on afterwards by translating one country's product.
Per flat, per month, right below. You can work out what it costs before you speak to anyone — which is more than the big names will give you.
What it costs
A few euros per flat, per month.
Prices are without VAT. You pay monthly and can stop at the end of any month. The first 14 days on one building are free, including us getting your files in. Setting up everything else costs €1,200 once, and nothing at all above 250 flats.
Questions
The ones people actually ask
What if it gets a number wrong?
Tap any figure and you see the bills, readings and rule it came from. If something went in wrong, you fix that and ask again. If we got a rule wrong, we fix the rule — and the old document stays exactly as it was, so you can still show what you sent and why. That's the thing you hand an accountant.
Do I have to log in to anything?
Not day to day. You connect it once and after that you work in ChatGPT or Claude. There is a website for settings and for looking back at who did what, but most people open it a few times a year.
Can it email a tenant without me knowing?
No. It writes the letter and shows it to you. Sending is a separate click by a person, and it's recorded who clicked it.
I'm not technical. Is this for me?
Yes — that's the point. If you can type a message to a colleague, you can use it. There's nothing to install, no settings to get right, and no vocabulary to learn.
You're an American company. What about European data rules?
Rentstag LLC is registered in Jackson, Wyoming, in the United States, with a European office in Amsterdam. European customers' files are stored in Frankfurt and never leave the EU unless you ask for that. We sign the standard European data processing agreement before we load anything, and the contract names our European representative. If your lawyer wants the paperwork up front, ask and we'll send it.
My stuff is spread over five programs and three spreadsheets.
That's normal, and it's fine. Send what you have, in whatever shape it's in. We start with one building, not everything at once, so you can see whether it works before you move anything else.
How long before I see something real?
Four working days from when you hand over the files for one building. Then you compare our statement against the one you made yourself. If the numbers don't match, you pay nothing.
Which countries and languages?
The site and the product speak the languages in the menu at the top. The yearly bill split follows local rules in the Netherlands, Belgium, Germany, Austria, France, Spain, Italy, Portugal, Poland, Czechia, Slovakia, Hungary, Romania, Croatia, Slovenia, Bulgaria, Denmark, Sweden, the United States and Australia. Letters to tenants come out in the tenant's language, whatever language you asked in.
What file types can you take? (for the IT person)
Spreadsheets and CSV, supplier invoices as PDF, photos of meters, and bank files in the usual formats — CAMT.053, MT940, BAI2 and OFX. Exports from DATEV and Pohoda too. If you have something else, send a sample and we'll tell you.
Start here
Give us one building. See it for yourself in four days.
Twenty minutes on a call, then we take one building of your choosing. We put your files in, you compare what comes out against what you'd have done yourself. If it doesn't match, you owe us nothing.