Balloon Partyner

Context

Balloon decorators used to spend days closing a quote: materials, labor and expenses had to be calculated, and then everything sent to the client. Balloon Partyner is a subscription platform that brings quotes, pricing, work orders, scheduling and finances together in one place.

What I built

• Proposals and work orders as PDFs, sent to the client over WhatsApp.
• A pricing engine covering materials, labor, expenses and margin, with a budgeted-versus-actual comparison for each event.
• Scheduling, client, material and cost records, and financial control.
• Recurring subscriptions through Stripe, in reais and dollars, with a free trial.
• Interface in Portuguese, English and Spanish.
• An AI assistant that answers questions about the business and leaves pricing calculations to deterministic code.

Technical decisions

• Math is done by code, not by the AI. The assistant uses vector search (pgvector) to understand the question, but pricing calculations are deterministic: the result of a calculation never depends on the model’s mood.
• Billing without surprises. Stripe webhooks are signed and idempotent, and subscribers keep the currency they signed up in (real or dollar) while the subscription is active.
• Data isolated per user. Row Level Security on every table, so each business only sees its own data.

Results

• Time to put together a quote dropped from 2 days to 3 hours.
• A live product with recurring billing in two currencies.