About Kalio
A booking tool for businesses where the schedule is the business.
Kalio is for the salon, the clinic, the studio and the trainer — anyone whose week is a grid of appointments and whose phone rings while their hands are busy. It gives you a page customers can book from without ringing at all, and a calendar that everyone working with you can see.
What we think is hard
Almost none of the difficulty in a booking system is the booking. It is the week refusing to be a grid: the break in the middle of the day, the Thursday you close at two, the colleague who does not start until eleven, the twenty minutes you need between appointments, the day the clocks go back and one hour happens twice.
So that is where the work went. The part of Kalio that decides which times to offer is a small, self-contained piece of the system with no database and no clock of its own, which means every one of those interactions can be tested directly rather than hoped about — including both daylight-saving transitions, in both directions.
Three commitments
A slot can only be taken once
Two customers can tap Confirm in the same second, and exactly one of them will get the appointment. This is enforced by the database rather than by application code checking first and writing second, because that check loses the race by construction. The person who came second is shown the nearest alternative times instead of an error.
Nothing is deleted
Retiring a service or a colleague hides them from new bookings and leaves every past appointment exactly as it was, still recording what was booked, with whom, and what it cost at the time. A price rise does not rewrite last year.
No passwords
You sign in with a passkey — your fingerprint, face or device PIN — so there is no password to choose badly, reuse, or have taken from somewhere else. Losing a device is recoverable by email, and a lost passkey can be removed without affecting the others.
What we have left out
Deliberately, and for now: text-message reminders, online payments, statistics, a waiting list, and a calendar feed. Each of these is a real feature that real businesses want, and each is better absent than present and half-working. The pricing page lists what is missing alongside what is included, so you can decide before you invest an evening in setting it up.
Where it works
Kalio is not built around one country. Currency, address format, phone numbers and public holidays come from a per-country configuration rather than being assumed, and every business sets its own timezone. The interface is available in English, Romanian and Hungarian.
Get in touch
If something here does not fit how your business actually runs, that is worth telling us — the awkward cases are the interesting ones.