Alfonso Payra
Senior Full-Stack Engineer & Technical Lead | CRO Growth Specialist
Senior Full-Stack Engineer and Technical Lead with 15+ years shipping production web, e-commerce, and AI-powered platforms — combining hands-on engineering with team leadership and AI-augmented development workflows.
By the numbers
CRO Case Studies
Sticky comparison header lifts pricing-page CTA clicks
The Problem
When pricing tables have extensive feature lists, users lose context as they scroll down. The tier names, monthly prices, and “Buy Now” CTAs scroll off the screen. For a new visitor who doesn't fully understand the platform yet, comparing features deep in the table creates cognitive overload because they can no longer see what price or tier corresponds to each column.
The Solution
I engineered a custom sticky table header that triggers as soon as the user enters the comparison section. As the user scrolls down through the feature breakdown, the header containing the tier names, pricing, and the highlighted “Most Popular / Best Value” CTA stays pinned to the top of the viewport, and automatically unpins once the user scrolls past the end of the table.
The Growth Impact
By keeping the recommended tier and the CTA constantly visible and in-context, we ran an A/B test comparing the static table versus the sticky header version. The variation with the sticky header reduced drop-offs on the pricing page and increased CTA click-through rate (CTR) by roughly 18–22%, significantly lifting overall checkout conversions.
Tech Stack
Experience
Founder & Lead Developer — Multi-Tenant E-Commerce SaaS Platform
Nov 2025 – Present · Remote
- Designed and built a Shopify-style multi-tenant SaaS platform enabling merchants to run independent stores with custom domains, full admin dashboards, payments, and AI-powered chat.
- Architected a monorepo (pnpm workspaces) spanning four applications — a NestJS/PostgreSQL API, a Next.js 15 storefront, a React 19 admin dashboard, and a marketing site — plus a shared package.
- Implemented true multi-tenancy (per-store branding, domains, payment credentials), a block-based page builder, dynamic collections, and MercadoPago checkout with order tracking.
- Built a live AI chat agent (Google Gemini with function calling) with human handoff, integrated with Meta Messenger/Instagram, plus abandoned-cart and win-back email automation.
- Deployed on Docker Compose with Caddy for automatic TLS across wildcard and custom merchant domains on a self-hosted VPS; encrypted integration credentials with AES-256-GCM.
Admin panel showcase
Dashboard
Store KPIs, latest orders and recent messages at a glance.
Products
Full product catalog with pricing, stock, tags and CSV import/export.
Collections
Dynamic, rule-based collections. The video walks through creating one, viewing it on the storefront, sending a message from there, and seeing it land in the Messages inbox.
Orders
Order list with status, totals and per-order messaging.
Messages
Live chat inbox for customer conversations, human or AI-assisted.
Customers
Customer directory with order history and lifetime spend.
My Store
Storefront branding, custom domain, currency and typography settings.
Pixels & Analytics
GTM, Meta, GA4 and TikTok pixels auto-injected into the storefront.
User Sessions
Session-replay recordings of real visitor behavior on the storefront.
Email Marketing
Subscriber growth and real-time audience segments.
CRO Segments
Auto-updating segments (VIP, churn risk, cart abandonment) ready to export to any ESP.
Google Kit
Google Merchant Center and Search Console integration for product feeds and SEO.
Coupons
Discount codes with usage limits, minimum purchase rules and email targeting.
Upsells
Automatic cross-sell offers triggered by a specific product or collection.
Pages
SEO landing pages published straight from the admin.
Full-Stack & Web3 Developer
Dec 2024 – Oct 2025 · Remote
- Built a browser extension letting users generate reviews and comments on any website ("flip"), including a monetization ad engine and a niche-based live chat.
- Designed a decentralized node network using NFT licenses, allowing users to run VPS nodes and earn project tokens based on uptime.
- Delivered the backend in Java Spring Boot and the frontend in Vue.js.
Developer
Feb 2024 – Dec 2024 · Remote
- Built a programmatic SEO platform integrating the Google Search Console API to surface ranking queries and auto-generate content and blog campaigns.
- Developed the backend with NestJS and MongoDB, integrating Google and OpenAI APIs; built the frontend with React and Vite.
Independent Developer — Freelance
Jul 2023 – Jan 2024 · Freelance
- Built Discord/Telegram community bots with AI-driven personalities capable of autonomous discussion and posting news via NewsAPI and the OpenAI API.
- Connected bots to a React and TRON blockchain roulette game enabling content creators to sell digital prizes, with fully automated prize flows.
Full-Stack Developer
Apr 2023 – Jun 2023 · Singapore, remote
- Led a full theme overhaul and shipped new features for a custom baby-clothing e-commerce store.
- Developed new backend components to support store operations.
Lead Developer
Sep 2022 – Apr 2023 · Montevideo, Uruguay
- Customized Node-RED to automate purchase flows and advanced customer support via APIs and webhooks.
- Designed workflows for order processing, product management, and email marketing, integrating AI to enhance customer interactions.
CTO & Lead Developer
Jan 2022 – Jul 2022 · Montevideo, Uruguay
- Designed an MVP for revenue-sharing between fans and artists using Solana and NFTs on Shopify.
- Built with Next.js and Rust; managed revenue and profit-distribution data for fans.
CTO
Sep 2020 – Jan 2022 · Montevideo, Uruguay
- Supervised a team of developers and collaborated cross-departmentally on a full-stack Shopify-based platform.
- Directed custom development and technical strategy across the organization.
Shopify Expert / E-Commerce Manager
Jun 2018 – Aug 2020 · Montevideo, Uruguay
- Specialized in Shopify (Liquid), HTML5, CSS, and PHP e-commerce development in close collaboration with UX/UI teams.
Instructor
Apr 2018 – Jan 2020 · Montevideo, Uruguay
- Taught Java application development, Unity/C# game development, and introductory web development (HTML5, CSS, JavaScript).
WordPress Developer
Feb 2017 – Jan 2018 · Montevideo, Uruguay
- Specialized in WordPress development, custom plugin development, and theme creation for client sites.
Additional Experience (2000–2017)
Education & Certifications
Universidad de la República (Udelar), Montevideo, Uruguay
Computer Engineering coursework (degree not completed)
2000 – 2002
Colegio de los Hermanos Maristas, Montevideo, Uruguay
Bachillerato, Engineering track
1991 – 1997
A.N.G.L.O., Montevideo, Uruguay
Advanced English
1998 – 2008
EF SET English Certificate — 66/100 (C1 Advanced)
Unity Video Game Programming, A+(2013–2014)