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Chris Maximin

@chrismaximin

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Principal Engineer at Gumroad who made hundreds of pages, APIs, and jobs 10–100 times faster as revenue tripled.

France

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What I'm looking for

I’m open to contract or permanent Staff Engineer, Principal Engineer, Senior Backend Engineer, and Site Reliability or Database Reliability Engineer roles.

At Gumroad, I was responsible for performance, database health, and scaling as revenue tripled. I found and fixed hundreds of bottlenecks, making web requests and background jobs 10 to 100 times faster.

I owned Gumroad’s production MySQL databases on AWS RDS, including upgrades, backups, disaster recovery, on-call response, and zero-downtime schema changes on tables with billions of rows. I also built Mediaconverter, an open-source Go service that cut video processing costs by 90%.

Since 2026, I’ve been building AI products and open-source tools end to end. My projects include an AI companion with long-term memory and real-time voice calls, plus cmail, an email client that uses an LLM to group messages and flag items needing action.

Earlier, I worked on XING’s notification services, which delivered tens of millions of push notifications and emails per day, and migrated FDJ / ParionsSport’s large Rails application from Rails 4 to Rails 5. I’ve also contributed fixes to Rails and other open-source projects.

Experience

Work history, roles, and key accomplishments

Current

Independent AI Product Developer

Current

Self Employed

Jan 2026 - Present (10 months)

Designed, built, and deployed AI products and open-source tools, including an AI companion app and an AI email client. Focused on LLM-powered features and real-time voice calls.

Ruby Ruby on Rails Go SQLite OpenAI API Swift Kamal AI Coding Agent LLM WebRTC Product Development

Career Break

Family

Nov 2024 - Jan 2026 (1 year 2 months)

Took time off to care for two young children.

Principal Engineer, Production Performance & Scale

Gumroad

Mar 2019 - Nov 2024 (5 years 8 months)

Owned production databases and performance, making pages and jobs 10-100x faster while revenue tripled. Led zero-downtime migrations on billion-row tables and cut video processing costs by 90%.

Ruby Ruby on Rails MySQL AWS RDS Elasticsearch Terraform GitHub Actions React TypeScript Performance Optimization Database Administration Zero downtime Migration On Call Incident Response

Senior Ruby on Rails Contractor

Alliants

Feb 2019 - Mar 2020 (1 year 1 month)

Designed database structure and developed core features for a guest-experience platform. Onboarded new engineers.

Ruby Ruby on Rails PostgreSQL GraphQL AWS Database Design Onboarding

Senior Ruby on Rails Contractor

JRNI / BookingBug

Aug 2018 - Oct 2018 (2 months)

Built groundwork for platform scaling and solved complex performance issues. Coached and mentored engineers.

Ruby Ruby on Rails MySQL Performance Optimization Coaching Mentorship

Senior Ruby on Rails Contractor, Backend Infrastructure

XING

Sep 2017 - Aug 2018 (11 months)

Worked on notification services delivering tens of millions of push notifications and emails daily. Improved performance and analyzed end-to-end delivery data.

Ruby Rails 5 Docker MySQL Redis Service Oriented Architecture Performance Analysis Notification Systems