Inspiration

In Latino neighborhoods, small shops run on two things no accounting app handles: cash and trust. The owner pays $20 for window cleaning out of the register, takes a $5 tip, and lets doña María take groceries home today and pay on Friday. That last part is fiado, and it lives in the owner's head or a paper notebook. When the notebook is wrong, the business loses money and sometimes a friendship. The bookkeeping gets done late at night, after closing, in time taken from family. We wanted to give that time back.

What it does

La Caha is a notebook you talk to. The owner taps once and says what happened, in Spanish, English or Spanglish, and it writes it down.

Daily cash log. "Pagué veinte por limpiar las ventanas." "Recibí cinco de propina." No invoices, categories or forms.
Fiado. "Le fié treinta a María por comida." "María me abonó diez." It tracks who owes, each thing they took, every payment, and the total still to collect.
Honest numbers. Fiado never counts as cash until it is paid, and a repayment is recorded exactly once, so the owner sees what has come in separately from what is still owed.
Listening mode. Say several things in one breath and it saves each one quietly, in order, without stopping to ask questions.
Hands-free. After one tap, the owner can record, ask "¿cuánto me deben?" and move between screens by voice, with hands busy at the counter.
Respectful by design. It says fiado, abono and saldado. It never says debtor or overdue, and never suggests chasing anyone.

How we built it

The app, database and interface are built on Base44. The voice is an ElevenLabs conversational agent embedded in the page. The agent does not touch the data directly: it calls a small set of tools (register an expense, register income, record a fiado, record a repayment, ask what is owed, summarize the business) that run inside the Base44 app. All the money rules live in two rules files in the app, so every balance is calculated from saved records and never by the language model. We built in stages: a working cash log first, then fiado, then language switching and hands-free control.

Challenges we ran into

Getting voice and app to talk. None of us had connected a voice agent to an app before. We proved it with a tiny test before the event started, then rebuilt it properly.
Too much politeness. Our first agent confirmed every entry and moved the screen after each one. On long sentences it lost track. We rewrote it to just listen and save, which made it faster and more accurate.
Ending the conversation. The agent would say goodbye and keep listening. We had to make the app itself close the session.
Two languages in one sentence. Real customers say "gasté twenty dollars en el parking". We had to teach it that Spanglish is not a request to switch to English.
Fiado bookkeeping. It is easy to count a fiado sale as income and then count the repayment again. Getting that rule right was the core of the project.
A first hackathon. A team of engineers and non-engineers, one build computer, and five hours.

Accomplishments that we're proud of

A working product that a shop owner could use on Monday, built in one afternoon.
Fiado handled the way the community actually practices it: by name, with partial payments, and with respect.
One sentence with four different transactions gets recorded correctly without a single follow-up question.
It works in the language people actually speak at the counter.
The numbers can be trusted, because the AI listens and the code does the arithmetic.

What we learned

Voice is only frictionless when the assistant stays out of the way. Removing confirmations improved it more than any feature we added.
Keep the language model away from the math. Let it understand people, and let plain code keep the books.
Build in stages that each work on their own. Every time we tried to add two things at once, we lost time.
The words matter. "Fiado" and "abono" earned more trust from the people we showed it to than any feature did.

What's next for la caha

A phone number to call, for owners who do not want an app at all.
Sign-in per business and per family member, so each person's entries carry their name and only the owner sees the totals.
A one-page summary for accountants and lenders, turning months of spoken records into the paperwork that cash businesses usually cannot produce when they apply for a loan.
Receipt photos matched against what was said.
Inventory by voice: "llegaron diez cajas de tomate".
Gentle fiado reminders the owner can choose to send, written the way a neighbor would say it.