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Klarhimmel

A recent job, in use since 9 September 2026.

A phone app for two hotels’ door codes.

I built a phone app for the owner of two apartment hotels. It shows the owner every key and its current code, and lets him make new ones without touching the old lock program. It has been live at both hotels since 9 September 2026.

Bring me the problem you have, and I will tell you what it would take.

The arrivals view of the door-code app: guests in the house and today’s arrivals with room and code, with one guest still missing a code.
Ett Smart’s door-code app, shown with example data.

Ett Smart · Live

The door-code app at two apartment hotels

The door-code app’s key list for an invented hotel site: keys with their codes and dates, a No code row, and tabs for two sites.
Ett Smart’s door-code app, shown with example data: the key list across two sites.

How it worked before

The codes lived in the lock program on one computer at the hotel. Of 97 entries in the owner’s log between November and April, 71 were someone looking up a code. Spare codes for a guest whose code failed were on a spreadsheet, and there was no way to see whether today’s guests had a code at all, except a guest calling to say they did not.

What it does now

Every arrival, and whether their code is in place.

A list of today’s arrivals at each hotel: who arrives, who has a code and who is missing one. The owner had asked for exactly this, and it did not exist anywhere before.

The arrivals view of the door-code app: guests in the house and today’s arrivals with room and code, with one guest still missing a code.
Ett Smart’s door-code app, shown with example data.

Every key, with its current code.

All 214 keys across both hotels, each with its current code, when it is valid and which doors it opens, read live from the lock system.

The key list on a phone: keys with codes and dates, and two site tabs.
The same key list on a phone, with example data.

A new code from the phone.

Staff, spare and room codes can be made in the app, with a record of every one and a daily limit.

Before

The key list with one key selected and a panel showing the chosen expiry date and a Create code button.

After pressing Create code

The confirmation card: a code created for key 3, valid until 8 Oct at 12:00, with a Copy the code button.

Ett Smart’s door-code app, shown with example data.

What happened

9 real door codes were made by the owner himself in his first session.

Live at both hotels since 9 September 2026.

The old lock program is untouched and still works as it did, so the owner’s one condition, that nothing already working should break, held from the first day.

What’s next

Next, the booking system tells the app when a guest checks in, and the app makes the code at that moment, so nobody has to. That is planned, not built: it waits on the hotel’s new lock server and an answer from the booking system’s supplier.

Pilot

A guest chat, in pilot

Guests ask in their own words, it answers only from documents the hotel has approved, says it is an AI, and hands over to a person when it should not answer. Staff test it before any guest sees it.

The guest chat on a phone: a guest picks Harbour House, asks how to book a laundry slot, and the assistant answers with an AI label.
The guest chat, shown with example data.

Want one of these for your business?

I built the Ett Smart door codes. Tell my assistant what you need and get an estimate.

It is free until you approve an estimate.