Looking for a job

Sergio Marquez

@marquezsd

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I build Ruby on Rails SaaS platforms, APIs, and full-stack products from discovery through delivery.

Argentina

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What I'm looking for

I'm looking to build SaaS, API, and full-stack web platforms where I can lead product discovery, systems design, and delivery with a collaborative engineering team.

I'm building Newton at KaiPod Learning, a Ruby on Rails platform with Hotwire Native mobile applications for a Partner Network of 150+ schools across 30+ states.

I lead product discovery from stakeholder interviews through implementation plans, and I deliver role-based web and mobile workflows, Action Cable messaging, and Stripe billing for customizable per-student plans.

Previously at Decisiv, I owned architecture and technical planning for the Pricing application, mentored junior engineers, and improved complex workflow page-load times by 20% to 80%.

I've modernized more than 500,000 lines of legacy Rails code, reduced CI workflow time from roughly 40 minutes to 8 minutes, and built resilient Rails APIs for BPme's high-traffic in-car fuel payment product.

Experience

Work history, roles, and key accomplishments

Current

Senior Product Engineer (Ruby on Rails)

Current

KaiPod Learning

May 2024 - Present (2 years 3 months)

Builds Newton, a Ruby on Rails platform with Hotwire Native mobile apps for KaiPod's Partner Network of 150+ schools. Leads product discovery, implements role-based workflows, and integrates Stripe billing.

Ruby on Rails Hotwire Stripe Product Discovery Linear Claude Pencil iOS Android

Lead Software Engineer

Decisiv, Inc.

Aug 2021 - May 2024 (2 years 9 months)

Owned architecture and technical planning for Decisiv's Pricing application within a six-engineer team, mentoring junior engineers and approving most pull requests. Reduced page-load times by 20% to 80% for large datasets and cut CircleCI workflow time from 40 to 8 minutes.

Ruby on Rails Ruby React Datadog APM CircleCi Capybara next_rails SQL JavaScript Testing Automation Mentorship Architecture

Ruby on Rails Engineer

Paper Kite Ltd

May 2016 - May 2017 (1 year)

Developed resilient Ruby on Rails APIs for BPme, a mobile payment application for in-car fuel purchases, designed to handle high traffic and integrate with external services, including payment services. Worked on BPme during its staged Jul 2016 rollout, with typical sub-second system response for site-status checks and pump authorization across a product with more than 100 designed screens and interaction states.

Ruby on Rails API Development Payment Integration High Traffic Systems External Services Integration