Senior Backend Developer · Cloud Automation Engineer
Luis Eduardo Marin Aguilera
I engineer backend systems that stay in production for years: cloud automation, AI integrations that run in production, and legacy stacks migrated to modern platforms. I wrote the first eighteen years of that by hand. Today most of the code is written by agents I direct, and the bar it has to clear has not moved.
Taking on select B2B contracts & technical partnerships
Lima, Peru (GMT-5) · Full overlap with US business hours
years shipping production systems, since 2007
one automation bot ran uninterrupted (2015–2025)
e-commerce brands on the B2B platform I build & operate
downtime on production deploys: blue-green, rollback in one command
About
Systems built to run for years without anyone touching them.
My specialty is bridging the gap between legacy operations and modern cloud architectures. A custom automation bot I deployed in 2015 ran uninterrupted for a decade, until the external platform it automated changed in 2025. Today I bring that same reliability to a multi-tenant operations platform I designed, built and operate end to end for a US e-commerce group: TypeScript and Bun on infrastructure I run, an authentication and permission model of my own design, a fleet of distributed workers, and AI insights verified against the data they cite. Most of that code is now written by AI agents I direct, which changed how fast it ships and not what it has to survive.
Selected Work
Ongoing platform work for a US group operating several e-commerce brands. I own the full stack: architecture, backend, frontend, integrations, build tooling and releases.
- Operations platform, built from zero: multi-tenant web app in Bun, TypeScript and SQLite, shipped as a single compiled binary: blue-green releases, health checks and one-command rollback, on infrastructure I harden and operate
- Security, designed and operated by me: sign-in, the permission model, the policy for irreversible actions and the backup strategy are all mine, built for an operation where a mistake moves real money
- Swapped the live system for its successor in a single day: forked the product to drop a module the client had outgrown, rebuilt the schema clean, migrated the tenant config straight out of the legacy database read-only so no integration had to be re-authorized, and cut the host over with reproducible scripts: six releases that day, zero incidents, the old database left intact as a fallback
- Distributed workers: compiled agents that dial home over WebSocket and drive real browsers, so lookups that need one still resolve; signed artifact delivery and a capability-based job queue behind them
- AI you can audit: a Gemini loop that decides what to query over the client's own data and writes the insight, with a verifier that resolves every figure it cites back to a real row. Plus email classification running in production across multiple brands
- B2B order management: a single-page web app on Google Apps Script for wholesale order operations against Shopify, with a custom Bun build pipeline and 19 versioned releases
- Built with agents, under engineering control: most of the code in this platform is written by AI agents I direct, against layered documentation loaded per task, rules the agents cannot lift, and automated checks that stop a release when something does not pass
- Engineering discipline: unit tests, layout and production smoke tests driven through Chrome DevTools Protocol against the compiled binary
Built Google Workspace Add-ons (Docs + Drive) with Vertex AI integration for a regulated-industry enterprise. Designed a batch migration pipeline for 50,000+ users using Cloud Functions, Pub/Sub, and Cloud Storage.
Independent technical audit of a Shopify Plus storefront, delivered to the engineering team that maintains it: performance and Core Web Vitals per template, accessibility, template architecture, and the full third-party layer, all measured firsthand through Chrome DevTools Protocol. It closed the open questions with numbers: the slow homepage turned out to be a third-party video app costing 2.6 seconds of main thread on mobile.
Extended microservices in Node.js and Go for fintech backoffice. Built AWS Lambda + Step Functions serverless orchestrations. Wrote Python scripts to diagnose and fix production transaction inconsistencies in DynamoDB.
Automation bot to register 2,000+ imported products in a government portal every quarter. Replaced a fully manual process that consumed 2 full weeks of the manager's time.
Problems I Solve
- You need senior architecture decisions without adding a full-time hire
- Your best people spend days every month on manual data entry that a script could do in minutes
- Your operation runs on spreadsheets and a dozen dashboards, and nobody can see the whole picture in one place
- You have valuable data trapped in legacy systems (Excel, SQL) that needs to talk to modern AI & Cloud tools
- You want to integrate AI into your workflows but need a production-grade implementation you can audit
- You need custom Shopify integrations that no plugin can handle, or an honest technical read on the storefront you already have
Best fit: startups modernizing a legacy stack, digital agencies that need senior backend on retainer, and companies adopting AI who need it running in production. Defined scope, B2B contract. Not a fit for equity-only work, unpaid trials, or projects without a defined scope.
What I Deliver
- Production Web PlatformsMulti-tenant systems in TypeScript & Bun, from database schema to zero-downtime deploys on hardened infrastructure
- Authentication & Access ControlTOTP, magic links, role-based permission trees, step-up re-auth, two-person approval, audit trails
- AI in ProductionGemini & Vertex AI integrations built to be verified and audited, including agentic loops over your own data
- Cloud & Serverless ArchitectureGoogle Cloud Functions, Pub/Sub · AWS Lambda, Step Functions · Linux VPS operations
- Legacy ModernizationVB/Excel macros migrated to modern Web & Cloud stacks
- Google WorkspaceAdvanced Add-ons, Apps Script WebApps (SPA), Drive/Docs/Gmail automation
- E-commerce Integrations & AuditsShopify GraphQL, ShipHero, Recharge, SPS Commerce EDI · independent storefront audits
Companies I've Worked With
Career Path
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2023 — Present
LEMAGUILERA TECH SOLUTIONS — Independent Consultancy Remote B2B contracts with US clients: Focus Solutions LLC (active: multi-tenant platform in production, Bun/TypeScript/SQLite), Onix (Google Cloud Partner), VLAS TECH (Romania)
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2021 — 2023
Kushki — Fintech, LATAM Backend Developer: Node.js and Go microservices, AWS serverless (Lambda, Step Functions, DynamoDB)
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2017 — 2020
Velogig & RMG — Lima, Peru Full Stack: data pipelines, ML pricing dashboard for Ripley, advertising tools for Grupo El Comercio
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2007 — 2017
Venezuela — Business Systems & Automation Payroll, inventory and invoicing systems, browser automation bots (VB.NET, PHP/MySQL)
Tech Stack
What Clients Say
"Luis demonstrated exceptional technical proficiency across multiple projects. His in-depth knowledge of Google Apps Script and Cloud Functions was instrumental in delivering Google Workspace add-ons and Vertex AI integration demos."
"The collaboration demonstrated exceptional technical proficiency and project management capabilities. The delivered Google Workspace widget met all specified requirements and significantly improved our operational workflow efficiency."
"A custom web interface was developed that integrated with our price prediction model, facilitating scenario visualization and accelerating decision-making. The tool was clear, functional and quickly adapted to our internal needs."
"We received a sales and inventory solution fully adapted to our operations, which we used for several years. The automation bot for product registration worked reliably for 10 years. The work was always punctual, effective and focused on solving real business problems."
Let's Work Together
$35–50/hr · scoped per project or ongoing contract
Tell me about the system you need to build, automate, or rescue. A 30-minute discovery call is enough to know if I'm the right fit, and if I'm not, I'll tell you.