Skip to content
AVAILABLE FOR CONSULTING

I AM ALEJANDRO CASTRO.Software Engineer.Frontend Architect.

Specializing in Legacy Modernization and Technical Debt Elimination. I transform unstable "vibes" into high-performance, production-grade engines.

Next.js
TypeScript
React
Astro
JavaScript
HTML5
CSS3
Node.js
Tailwind CSS
PostgreSQL
GraphQL
Prisma
Turso
Shadcn/UI
Framer Motion

The Work

I specialize in de-risking complex frontend migrations and building high-performance systems for enterprise-scale platforms.

Screenshot of the The Great Framework Pivot project
Case Study 01

The Great Framework Pivot

The Mess

"We were trapped in a "Gatsby Build Tax." Every minor content change triggered a 20-minute CI pipeline because our HOC patterns were forcing double-generation of 500+ static pages."

The Outcome

Build times dropped from 20 minutes to 90 seconds. Lighthouse scores jumped from 45 to 98, directly correlating to a 15% increase in organic traffic.

Screenshot of the Distributed State Orchestration project
Case Study 02

Distributed State Orchestration

The Mess

"I inherited a jQuery monolith where 100+ WebSocket updates per second were locking the main thread, making the dashboard unusable for high-frequency operators."

The Outcome

Eliminated 90% of UI lag and race conditions. Operator efficiency increased by 20% due to the zero-latency feedback loop.

Screenshot of the Off-Main-Thread Performance Engineering project
Case Study 03

Off-Main-Thread Performance Engineering

The Mess

"The client demanded heavy tracking (HubSpot/GTM) and a 3D Hero section, but refused to accept anything less than a 95+ Lighthouse score."

The Outcome

Achieved a 99 Lighthouse Performance score. LCP was reduced by 2.5s while keeping all marketing functionality intact.

Screenshot of the Micro-Frontend Orchestration project
Case Study 04

Micro-Frontend Orchestration

The Mess

"We had three autonomous teams stepping on each other's toes in a massive monolith. A bug in the "Support Chat" would regularly crash the "Payment Gateway," and deployments required a 4-hour manual regression test."

The Outcome

Deployment frequency increased from once a month to multiple times a day. We achieved 100% fault isolation: if a Remote crashed, the Shell simply showed a fallback instead of a White Screen of Death.

Engineering R&D

Experimental

Deep dives into low-level browser APIs, state synchronization, and high-performance rendering. Where I push the limits of the web platform beyond standard application development.

Screenshot of Excalidraw-ish
Excalidraw-ish
Canvas Engine
A high-performance infinite-canvas engine built from scratch. Implements low-level browser rendering, custom event piping, and high-frequency coordinate mapping.
HTML5 CanvasVanilla JSCoordinate Systems
Screenshot of Content Vault
Content Vault
SaaS Infrastructure
A multi-tenant content infrastructure utilizing isolated workspaces and secure state synchronization. Engineered for organizational data isolation and scale.
Next.jsTailwindTypeScriptPrismaTurso
Screenshot of Brakaru
Brakaru
Island Architecture
A Geo-Spatial intelligence pipeline that extracts tourist points of interest from unstructured YouTube data. Transforms "vibes" into high-precision, personalized road maps.
AstroReact IslandsAI/LLMsGeoJSONTurso
Cooking...

More experiments with WebGL, AI Agents, and CRDTs coming soon.

Alejandro Castro Quintero

The Philosophy

In an era where AI can "vibe" out a UI in seconds, my role has shifted from writing lines of code to engineering resilience. I believe that the right tool for the right job—combined with strict technical standardization—is the only way to move fast without breaking the system.

Architecture over Artifacts

I don't just deliver features; I build scalable patterns. My custom UI libraries and state engines are designed to be refactored and extended without friction.

Tooling for Velocity

The right tool for the right job brings the velocity and standardization needed to ship production-grade code. I build the infrastructure that makes quality inevitable.

Performance as a Feature

Clean code is irrelevant if it's slow. I utilize low-level browser APIs and React internals to squeeze every millisecond of performance out of the render path.

Systems over Snippets

AI is great at snippets; I'm focused on the system. I establish the technical guardrails that allow teams to scale without accumulating architectural debt.

From the Blog

JavaScript has evolved from a utility-heavy language to a platform orchestrator. Discover how Temporal, structuredClone, and the using keyword are killing your dependencies.

Docker is for servers. Nix is for humans. Learn why "Works on My Machine" is a lie, and how Nix Flakes + Direnv can save your sanity.

Tailwind won the war for utility classes, but architecture is more than just class names. Learn how @layer, @scope, and Container Queries are redefining scalable CSS.

Let's talk
Engineering.

I'm always open to discussing complex migrations, performance bottlenecks, or joining high-impact teams.

Currently interested in:

  • Architectural Consulting
  • SaaS Infrastructure
  • Performance R&D