Skip to content
martinespinosa.dev_

// lab

Try it before you hire me.

Six things I build for businesses, running right on this page: an AI assistant, payments on several platforms, PDF documents, automations, a SaaS dashboard and integrations. The businesses and data are samples: nothing is sent or charged.

// 01 · AI assistant

An assistant that answers, quotes and books

This is the chat of Tracción, a fictional tire shop. Ask about prices or payment options, or ask for an appointment: it checks the schedule, the booking shows up on the side and you can download a PDF confirmation or add it to your calendar.

  • Booking through a validated tool

    The AI doesn’t just “say” it booked: it calls a function that checks the schedule and rejects taken slots.

  • Daily spending cap

    Each visitor and the whole site have a daily limit. Cost is checked before calling the model.

  • Fallback without AI

    If the cap is reached or the provider fails, a rule-based assistant takes over. Nobody is left without an answer.

  • Only the business’s data

    Prices, hours and promotions come from the loaded data; when it doesn’t know, it says so.

The same kind of assistant, answering on real WhatsApp: Nácar, a coffee and tea house

Tracción · Tire shop

Assistant · replies instantly

AI

// 02 · payments

Get paid on the platform your customer uses

A sample checkout with six ways to pay. Pick the currency and the platform and pay: you’ll see how the payment notice arrives, how it is verified and the receipt that is issued. It is a simulation: nothing is charged and no platform is contacted.

  • Multiple currencies

    Each platform only shows the currencies it accepts.

  • Verified notice

    The payment notice is signed and checked before the order is marked as paid.

  • No double charges

    If the same notice arrives twice, it is processed once.

  • Automatic receipt

    Once approved, a PDF receipt is issued.

And a full online store, from cart to payment, with stock per size and color: Serrana

Payment platform

Simulation: no data goes to the platforms. With a real client, each one connects with its own account and keys, in test mode first.

// 03 · documents

Quotes, invoices and contracts as PDF, instantly

Fill in the details and download the document. The system does the math, applies taxes and discounts, and the contract is signed on screen with a fingerprint that detects any change.

What about an assistant that answers from your documents and cites the source? See it at Estudio Paz

Items

In the real version, the CAE comes from ARCA, Argentina’s tax agency (WSFEv1), and the QR leads to its verification. Here the CAE and QR are SAMPLES.

Preview

Documents are generated in your browser and carry a “SAMPLE” mark.

// 04 · live automation

From the form to the sheet, the CRM and the inbox, on its own

Fill in the contact form of a sample business and watch each step run. The email and the team alert show up in the inbox below: nothing is sent to anyone.

Three real n8n workflows with AI, to run node by node

Contact form

  1. 01

    Form received

    The request comes in with its data.

  2. 02

    Validate and clean

    Valid email, trimmed text, no duplicates.

  3. 03

    Classify

    Priority by budget and urgency; interest by keywords.

  4. 04

    Spreadsheet

    Adds a row with the whole request.

  5. 05

    CRM

    Creates the deal in the right column.

  6. 06

    Reply to the client

    Personalized email with the next step.

  7. 07

    Team alert

    Message to the team channel if it is high priority.

DateNameCompanyIndustryUSDInterestPriority

Send the form to see what arrives.

Everything runs in your browser. With a real client, each step is a service: Google Sheets, a CRM, the business’s email and Slack or WhatsApp.

// 05 · SaaS dashboard

One platform for many businesses

A sample dashboard with several accounts, each with its own currency, plan and quotas. Switch businesses, browse the sections and try upgrading the plan.

A full management dashboard with sales, collections, debtors and stock: Grupo Molle

Bookings per day · last 14 days

Upcoming bookings

TimeCustomerServiceStatus

Each account only sees its own data. Quotas are enforced on the server before every action that costs money.

// 06 · integrations

It connects with what you already use

These are some of the platforms I integrate systems with. Tap one to see how it connects: account authorization, encrypted key storage and a connection test (simulated).

A WhatsApp assistant on the official Meta API, in support or sales mode, with an inbox for the team

Payments

  • Mercado Pago
  • Stripe
  • PayPal
  • Dodo Payments
  • Pix
  • Bank transfers

Messaging

  • WhatsApp Business
  • Telegram
  • Email (Resend, SMTP)
  • Instagram

Productivity

  • Google Calendar
  • Google Sheets
  • Google Drive
  • Gmail
  • Microsoft 365
  • Outlook

Invoicing

  • ARCA (Argentine e-invoicing)
  • PDF and QR
  • VAT ledger

Artificial intelligence

  • Claude
  • Gemini
  • OpenAI
  • Document reading

Automation and data

  • n8n
  • Zapier
  • Make
  • Webhooks
  • PostgreSQL
  • REST API

Websites and stores

  • WordPress
  • Shopify
  • Tiendanube
  • Astro

Using something else? If it has an API or exports data, it can almost certainly be connected.

Want something like this for your business?

Tell me what you need and I’ll reply by email with a proposal.

Get in touch