My grandfather's shop had never used product codes

Sanitarios Moldes is my grandfather's plumbing and fixtures shop. It's 50 years old and has never had a system: sales, stock and prices live in the memory of the people at the counter. To know how the day was going, my grandfather had to be there.

A while back I had built him a website with photos of the shop, and nobody used it. This time I wanted to start with what the business actually needed, not with the website.

First, a code

The first thing I asked was whether the shop used product codes. The answer was no. So the first step wasn't digitizing something that already existed: it was creating a code for every product. Everything else comes from that.

What I built

• —The counter. You look up a product by code or name, the price shows up, the sale is recorded and stock goes down by itself.
• —The online catalog. Customers put together their order from their phone and pick it up at the shop. They pay at pickup.
• —Orders. A screen to see web orders and mark them ready or delivered. If one is cancelled, the stock comes back.
• —My grandfather's dashboard. What was billed today and this week, the latest sales, what's running low and pending orders. Designed to be understood at a glance, not as a panel full of numbers.

I tested it end to end: an order from the catalog, marking it ready, delivering it, and watching the stock and the dashboard update. The products loaded are still placeholders: the real catalog gets built product by product.

What I left out on purpose

• —Cameras. For that it makes more sense to buy cameras that come with their own app than to build video from scratch.
• —Online payment. For now you pay at pickup.
• —What it takes to use it with real customers, like user accounts and a cloud database. First I wanted to prove the flow made sense.

What I take from it

• —Before coding, ask how the work gets done today. If I hadn't asked about codes, I would have built on something that didn't exist.
• —In a small business, every new thing to learn has a cost. That's why the product code is the only new thing: everything else follows from it.
• —Not everything has to be built. Cameras can be bought.