Running an inn, you rely on all sorts of "systems" every day.
The one that troubled me most was the "site controller" — the thing that syncs vacancies across several booking sites.
When a booking comes in on Airbnb, close the dates on Booking.com and Agoda.
Do this by hand and, sooner or later, a double booking will happen.
So most inns pay from a few thousand to tens of thousands of yen a month for a sync system.
Looking up the going rate, even the tier a small inn could realistically use costs 40,000 to 140,000 yen a year.
Money that quietly goes out every month, though the number of rooms doesn't grow and neither do the bookings.
"Couldn't I build this myself?"
That thought came in June this year.
I can't program.
I can lay the floor of an old farmhouse, but I can't write code.
What made it possible anyway was having AI beside me.
When I said in plain Japanese, "I want to build a server that merges the booking sites' calendars into one and serves it", the AI wrote the code and took it all the way to installing it on the server. All I did was decide the direction and press the "approve" button in the browser.
It felt exactly like fixing the old house with my own hands.
DIY the inn's system, the way you'd assemble a bookshelf.
Of course, it wasn't all smooth sailing.
I deleted a test booking, but the block wouldn't disappear from the booking site.
Delete it and delete it again, and the data came back like a zombie.
The cause was an "infinite sync loop", a pitfall peculiar to this kind of system (the whole story, with the fix, is in Chapter 5 of the course).
There was also a time the server went silent because a single stray dot had crept onto the end of a URL.
The hours spent finding the cause turned out, in hindsight, to be the best teaching material of all.
The finished system has run quietly all summer, for 0 yen a month.
https://brain-market.com/u/kinako666/a/b4cDO1UjMgoTZsNWa0JXY
The fixed cost saved goes to timber and paint for the inn, and to looking after our guests.
And above all, what remains is the reassurance that "if it breaks, I can fix it myself".
I've put the whole story into a Brain course, "Free Site Controller Build Guide" (in Japanese).
One thing I decided while making it:
never make the reader copy and paste code.
Transcribing long code means one missing character becomes an accident (just as I tripped over a single dot). So I devised the delivery so that "press one button and the server assembles itself". All you need is a browser and a free account.
To those running a small inn, a guesthouse or a whole-house rental:
if you let out a small sigh every month at the system fee, take a look.
https://brain-market.com/u/kinako666/a/b4cDO1UjMgoTZsNWa0JXY
The first 10 copies are at a special price (2,980 yen) for those who will leave a review.
As a thank-you for reviewing, there's also an invitation to a buyers-only Discord community.