Sergei Smagin

smaginsergey1310@gmail.com cal.com/smagin github.com/s-mage linkedin.com/in/s-mage

Full-stack Software Engineer who works in a team and owns projects he's been entrusted. Works best in diverse and fast-paced environments.

In 2026, I'm good at communicating my intents to LLMs and not letting them get away with slop. I like my Builder / Sweeper hats from the Boris Cherny classification.

Work Experience

Feb 2022-Present Nomadix US, UK remote Lead Developer
  • Transformed a one-man-developed app into a fully functional, market-ready product. Resulting in ability to market it as part of the company portfolio and huge decrease in crashes.
  • Promoted and helped achieving consistent and better-than-before UX across the products. UX became an important selling point
  • Led a project to keep on-site client hardware up to date, which saved thousands of hours of manual work
  • Helped the team to set up processes while merging several companies to improve confidence on deploys and reduce synchronous actions done by multiple people.
    • Introduced code reviews
    • Introduced feature flags
    • Added linters to CI, get rid of flakey tests
    • Promoted a testing/deployment strategy that doesn't rely on a single person
  • Helped with a Theseus ship-style rewrite of a captive portal configurator, with a focus on UX
  • Contributed necessary bug-fixes to several open-source projects, namely Ruby on Rails and rails-i18n
Apr 2019-Feb 2022 Gleam Australia remote Software Engineer
  • Got team buy-in & lead organization-wide transition to using feature flags to enable developers to ship smaller chunks of changes & simplify PR reviews
  • Radically improved the campaign creation form in the app:
    • Reduced loading time from 6s to under 1s
    • Better UX including inline validation for configuration & 3rd-party integrations
    • Cut the time users spent on setting up an average campaign in half
    • Added validation errors reporting for further monitoring
  • Optimized Pagespeed score of landing pages from single digits to 95/100 to improve UX and Google rankings
  • Optimized API endpoints. The "bootstrap" endpoint loads under 1s now.
  • Contributed necessary bug-fixes to several open-source projects, namely bullet and rack-mini-profiler
2016-2019 Codeart Estonia remote Software Engineer
  • Reimplemented in-app payment (Stripe/Appstore/Google store) & authorization system for an Ionic app. It became a lot more reliable.
  • Developed sophisticated authorization systems for a number of marketplaces for centralized data access control.
  • Had 9 contracts and 6311 hours on Upwork with 100% job success
2015-2016 AVODN Mexico remote Lead Developer
  • Organized developers to work on DMCA system
  • Designed a pipeline of services to find videos, check fingerprints, and send emails if they were subjects to DMCA. Added monitoring for every step.
  • Built a Clojure/ClojureScript CMS for all this
2013-2015 GTFLIX TV Czech Republic remote Junior developer → Developer
Developed a salary calculator, worked on a stolen cards detection system. Created an internal alternative to Percy.

Education

2014-2016 M.S. Computer Science, Tula State University, Tula, Russia
2012-2015 Qualified Specialist in IT Translation, Tula State University, Tula, Russia
2010-2014 B.S. Computer Science, Tula State University, Tula, Russia

Technologies and Languages

Languages: Ruby, Javascript, CSS
Technologies: Kubernetes, PostgreSQL, Ruby on Rails, Web Components
Rusty: Ansible, Vue.js, Clojure, MySQL, React.js, Angular 1