AJ Villalobos.

Senior Product Engineer

I’m a senior product engineer with twelve years of Ruby on Rails experience building production software for fintech, healthtech, and SaaS teams across the US, UK, and Australia. I work closely with engineering and product teams to turn operational needs into reliable software. Rails is my primary stack, and I use AI coding tools as a practical part of development. I’m open to full-time senior product engineering opportunities, especially Rails and backend product work.

Work

2025–now

Lavanda

Senior Ruby on Rails Developer · UK, remote

I work on booking and leasing features for a property management platform used by build-to-rent and co-living operators.

  • Made its DocuSign integration more flexible by replacing application-defined prefilled fields with client-configured Sender Fields.
  • Built booking-import tooling for onboarding new clients.
  • Work directly with product and implementation managers to investigate questions, clarify technical constraints, and resolve client concerns.
2024–25

ShiftCare

Ruby on Rails Engineer · Sydney, Australia

Shipped customer-facing and internal features for an aged-care platform, Rails APIs with a Vue frontend, balancing usability with maintainable backend architecture.

2023–24

Radiopaedia

Ruby on Rails Developer · Australia

Improved mobile UX and key page layouts for one of the largest radiology references on the web, TypeScript and Preact components inside a Rails app.

2019–23

Kangarootime

Ruby on Rails Developer · United States

Maintained and extended a legacy childcare-center platform used across the US. Refactored its core status-tracking model and built COVID screening and onboarding features during a high-change period.

2017–20

BloomSolutions

Software Engineer · Makati, Philippines

Built features for BloomRemit, a cryptocurrency-enabled remittance platform that facilitated over $120M in customer transactions, with an emphasis on tested, maintainable service patterns.

2014–18

Earlier

POS integrations and a Messenger bot at Tanda, booking platforms and private gems at Aelogica, Rails and Ember work at Proudcloud, and Rails features at YouSource. Full history in the PDF resume.

Projects

Brand

Arqen.dev

My self-funded software studio for Philippine businesses. I design, build, operate, and support its products end to end, covering product decisions, engineering, infrastructure, and customer support.

Inventory

KeepTrack.ph

Inventory management software used by four Philippine businesses, with stock tracking, expiry alerts, purchase orders, supplier management, and recipe costing. The product is maintained and supported for its existing customers.

Payroll

Timekeep.ph

My primary self-funded product: payroll, attendance, and scheduling software for Philippine businesses.

  • My work spans product decisions, engineering, infrastructure, and customer support.
  • The platform has recorded more than 17,000 attendance entries and generated over 1,300 payslips across 89 finalized payroll runs, representing more than ₱6.9 million in gross payroll calculations.
  • Handles Philippine requirements including government contributions, withholding tax, holiday pay, scheduling, facial-verification attendance, and employee self-service.
Healthtech

SigRx.app

A digital prescription and patient-record application originally built for a doctor operating a laboratory. It is in use today while I validate whether the product should be expanded for more Philippine doctors.

Acquired

Privacy-first link shortener

A simple Bitly alternative built for GDPR compliance. Launched as a paid product and later acquired by one of its early users.

Open source

Clover Ruby gem

A Ruby wrapper for the Clover POS REST API. Archived, then forked and used in other teams’ production integrations.

Resume

PDF

Hiring or screening? The resume has the full work history, education, and contact details in a printable page.

Download the resume (PDF) ↓