From walking the floors with a notebook to bills that collect themselves

Owner-operated apartments, dorms, and room rentals of roughly ten to eighty rooms, where the owner or one staffer does everything. Timely, too: consumer-protection rules for residential rental now require water and electricity billed at the utility's actual rate, with units used and price per unit shown on the bill. A notebook and a photo of an Excel cell do not show that. An itemized bill does.

The build turns the monthly loop into one straight path: reading in, bill out, money matched to the right room.

• Phone-first meter entry per room, with a photo of the dial saved next to every reading
• Bills computed the legal way: rent, units used times the actual utility rate, itemized line by line
• A PromptPay QR per room with the exact amount encoded, delivered through the building's LINE
• Slip upload by the tenant; the room flips to paid only when the owner confirms the slip
• A floor grid of every room: paid, pending, overdue, at a glance
• Printable receipts and a monthly summary the owner can hand to an accountant

• The full codebase in the owner's own repository
• Hosting, domain, and LINE wiring set up in the building's name
• A plain-language runbook: new tenant in, tenant out, rate change, voiding a wrong bill
• A recorded handover call the owner can rewatch instead of re-asking

1. Map

   A short first week

   I walk one full billing cycle with the owner, notebook to Excel to LINE to slips, and write down every place a number gets retyped.

   A one-page scope: the billing formula, the slip rule, and what stays manual on purpose.

2. Shape

   Inside the same fortnight

   I design meter entry for a phone held in one hand in a stairwell, and the floor grid for a five-second answer to 'who has not paid'.

   Clickable screens the owner approves before any backend is built.

3. Make

   The build weeks

   I build reading, bill, QR, and slip as one tested path against one real room before scaling it to the whole building.

   A real bill for a real room, paid through its QR, confirmed from a real slip.

4. Prove

   One billing cycle

   We run one full billing month in parallel with the notebook and compare every room's number.

   A reconciliation of every room, with every mismatch explained and fixed.

5. Hand-off

   The final days

   I move every account into the building's name and walk the owner through a month end without me.

   The keys: code, hosting, accounts, and a runbook in plain Thai and English.

• Quoted per project after a short scope call. You see the full number before any money moves.
• Payment is phased against the build: a deposit to start, a milestone at the first real bill paid by QR, the balance at hand-off.
• Fixed scope, fixed price. No per-room monthly fee: the building owns the system outright.

• Meters are read by a person; this build makes the reading fast and traceable, it does not install smart meters.
• Tenants pay by transfer or PromptPay and already talk to the building on LINE.
• One owner-approver and one rate card for the building during the build.

• No accounting system replacement; the monthly summary feeds your accountant, it does not become one.
• No tenant-screening or contract management in the first scope; billing is the bleeding wound, so billing goes first.
• No automatic bank-statement matching on day one; the slip-confirm flow is deliberate, so the owner stays in control of what counts as paid.

The photo next to the number is the whole system

Billing software for a small building lives or dies on one moment: a tenant disputing a number. So the decision that matters is saving a photo of the meter dial next to every reading, every month, automatically. The bill stops being the owner's word against the tenant's, and becomes a number with a picture behind it. Everything else, the QR, the slip flow, the floor grid, works because that trust exists.

The result

Built so that month end shrinks from days of walking, typing, and squinting at slips to a morning of confirming. Bills go out itemized the way the rules now require, money lands against the right rooms, and the arrears view replaces awkward guesswork with a list.

What it proves

That back-office software earns its keep by deleting retyping, not by adding dashboards. Capture a number once, with proof, and let it flow to the bill, the QR, and the books on its own.