Recebe Avisa

Technical decisions

1. 01

   OCR never blocks the record

   The scan route always answers success. If OCR fails, comes back unreadable or low-confidence, the flow degrades: the label is recorded anyway and the doorman confirms the resident from ranked suggestions or manual search. A front desk at peak hour cannot stall over a crumpled label — and that is the difference between a system that gets used and one that gets abandoned in week one.

2. 02

   Fuzzy search instead of exact matching

   The name printed on a label almost never matches the registry: it arrives abbreviated, under the buyer's name, without accents or misspelled by the sender. Matching uses trigram similarity plus per-resident aliases, returning ranked suggestions rather than a binary hit or miss.

3. 03

   Multi-tenant by column, filtered in every query

   Every table carries the building identifier and no query ever crosses tenants — that's an architecture rule, not a convention. A building-management SaaS that leaks data between clients does not get a second commercial chance.

4. 04

   Personal data out of telemetry, with an automated gate

   Telemetry is OpenTelemetry collected by an agent that strips PII inside the VM, before anything leaves it. A PII checker runs in CI and breaks the build if personal data shows up in a span, metric or log. The gate isn't theoretical: a real leak, caused by how the ORM interpolates values inside SQL, is what drove query normalization before they become span attributes.

5. 05

   Zero cost as an architectural requirement

   The whole MVP runs on free tiers: an ARM VM on Oracle Cloud, a thousand OCR requests a month, WhatsApp Cloud API and free-tier observability. Managed queues and paid services only enter past fifty buildings. Declaring the cost constraint up front avoids the architecture that gets expensive before it has a customer.