Software architect & technical lead

I help teams make difficult software work.

I'm Arvin, a hands-on software architect and technical lead with 16+ years of experience. I work with product and engineering teams to make clear technical decisions, build across the stack, and deliver reliable systems in production.

Interested in architecture, technical leadership, and senior engineering opportunities.

Teams I've worked with

Experience across AOTXnologies, Kinetic Innovative Staffing, Optimum Innovatus, Pointwest Technologies, Trinko, Willis Towers Watson.

Arvin Jayson Castro, Software Architect and Technical Lead

16

Years in software

Still hands-on.

Understand the problem

Learn how the product, team, and constraints actually work.

Make the right decisions

Turn complexity into clear, maintainable architecture.

Deliver and stay involved

Work through design, build, testing, and release - with the team.

Selected experience

A track record of building and leading.

Some of the teams and systems I've worked with.

View full experience
  1. Aug 2025 – Apr 2026

    Tech Lead, Software

    BaseOfUI · Contract

    Led product and technical direction for a multi-tenant SaaS platform for building and operating websites, forms, content, and internal business workflows.

    • Architected and delivered core capabilities across authentication, organizations, RBAC, page building and publishing, forms and submissions, file storage, templates, and applications.
    • Directed end-to-end delivery from product discovery and UX design through architecture, implementation, testing, and release planning - hands-on across frontend, API, and data layers.
    • Multi-tenant SaaS
    • RBAC
    • Page building
    • Forms
  2. Dec 2024 – Aug 2025

    Senior Full-Stack Engineer

    Comrise Risewave · client: Willis Towers Watson

    Delivered enterprise-grade Income Review modules supporting financial data processing.

    • Designed a configurable reporting engine with rule-based validation pipelines.
    • Built scalable backend services focused on performance, reliability, and maintainability, and modeled database schemas and migrations for evolving business requirements.
    • Reporting engine
    • Validation pipelines
    • Backend services
  3. Feb 2020 – Nov 2024

    Solutions Architect (Hands-on Full-Stack)

    AOTXnologies

    Architected and delivered a production-grade multi-tenant Learning Management System supporting scalable tenant growth.

    • Designed architecture across frontend, API and data layers as the primary technical driver, implementing tenant isolation and role-based access control for secure multi-organization environments.
    • Established CI/CD pipelines and engineering standards for production readiness, and led technical direction while actively delivering across the full stack.
    • Multi-tenant LMS
    • Tenant isolation
    • GraphQL
    • CI/CD
  4. May 2016 – Feb 2020

    Senior Full-Stack Developer

    Kinetic Staffing

    Delivered an enterprise organization and role management platform.

    • Built a dynamic form builder and reporting dashboards end-to-end.
    • Designed REST APIs and optimized database models for performance and scalability.
    • Form builder
    • Dashboards
    • REST APIs

Earlier: Rumble Asia / Coffey International (2013 – 2016) · Trinko Inc / Optimum Innovatus / DBSoft / Pointwest (2010 – 2013)

BS Computer Science, University of Santo Tomas (2006 – 2010)

What I bring to your team

Architecture. Engineering. People.

Three areas I focus on to help teams ship and sustain good software.

Architecture & judgment

Clarifying requirements, defining boundaries and interfaces, and making trade-offs understandable.

Read a case study

Hands-on engineering

Working across frontend, backend, integrations, debugging, testing, and production delivery.

See what I've built

Team & delivery

Working with engineers and product stakeholders to clarify scope, resolve blockers, and maintain shared understanding.

Explore my experience

Selected work

Real systems. Real problems.

A few projects that show how I work - from idea through to production.

airunote

Knowledge workspace

Live

One content system for nested notes, boards, canvases, study views, and public assessments.

My contribution. Product model, workspace behavior, editor flows, permissions, and full-stack delivery.

Open airunote.com

baseofui

Multi-tenant workspace platform

Live

A configurable system for websites, forms, files, publishing, portfolios, client workflows, and team operations.

My contribution. Page builder, tenant isolation, RBAC, installable apps, public portals, and per-organization admin workspaces.

Open baseofui.com

Coach Browser

Local-first research workspace

Windows prototype - not publicly released

Keep research, browser tabs, notes, canvases, files, and next steps together inside focused desktop workspaces.

My contribution. Windows desktop shell, isolated browser tabs, local files, Markdown notes, canvas pages, capture flows, keyboard navigation, and packaging.

Coach Browser research workspace with desktop workspaces, browser tabs, notes, and local files.

Writing

How I think about software.

Working Fundamentals is my guide to building software that stays understandable as the users, rules, data, and stakes keep changing.

Thirteen short chapters on state, data, boundaries, failure, testing, and performance — the decisions that decide whether a system is still workable a year later.

Working Fundamentals, a printed guide by Arvin Jayson Castro

Let's work together

Looking for an architect who stays hands-on?

I'm interested in architecture, technical leadership, and senior engineering opportunities. Tell me about your team, the role, and the engineering problems you're working through - I'll tell you honestly where I could help.

You'll speak and work directly with me.

adapts to any system