Jinelle
Baterna
Software Engineer. Based in Toronto, Canada.
I build fast, well-tested React interfaces that hold up in production, but what I actually care about goes deeper than shipping a component that works: performance, reliability, and code that's optimized and built to be reused instead of rebuilt every time requirements change. I loop in AI for prototyping, reviewing my own code, and testing, but I still hold what it gives me to the same bar as my own work: does it perform, is it accessible, is it actually good code. The small stuff is what shows it: a render that doesn't jank, a design that still looks right after handoff. Most of my best work happens where design and engineering overlap.
Experience
Recent roles. Full history on the résumé.
Mosaic Manufacturing Ltd
- React
- Redux
- TanStack Query
- TypeScript
- Styled Components
- Figma
- Jest
- React Testing Library
- Playwright
- Proposed and led a component refactor, negotiating timing to protect the release and de-risking it with new test coverage. Cut code duplication 30 to 40% and sped feature rollout 20%.
- Main owner of frontend UI for a 6+ engineer team, handling architecture decisions, PR review, and onboarding new hires. Production bugs dropped 20%.
- Partnered with the product designer to catch design-system and code inconsistencies before implementation, improving design-to-dev handoff speed 25% and keeping products visually consistent.
Mrkdwn, Inc.
- React
- Redux
- HTML
- CSS
- Sass
- REST APIs
- Sketch
- Zeplin
- Built a single-page React application for a Philippines-based deals and discount aggregator site, translating Sketch and Zeplin designs into production UI, including deal-discovery filters and a CMS for admins.
- Added server-side rendering so search engines could actually index the pages, and wired up REST API integration with axios to pull in live data.
- Worked with backend engineers on caching and other performance improvements, and used analytics data to grow engagement from social and organic search, taking daily sessions past 1,000.
Skills
What I reach for, day to day.
Languages
- TypeScript
- JavaScript
- HTML
- CSS
- Sass
- SQL
AI-Native Development
- Claude Code
- AI-assisted code review
- Test and spec generation
- Prototyping and library evaluation
Architecture & Patterns
- Design systems
- Design tokens & theming
- Reusable component libraries
- State management
- REST API integration
Testing
- Jest
- React Testing Library
- Playwright
Frameworks, Libraries & Tools
- React
- Next.js
- React Native
- Node.js
- Redux
- TanStack Query
- Styled Components
- Tailwind CSS
- Git
- GitHub
Performance
- Render optimization & memoization
- List virtualization
- Web Workers
- Code splitting
- Core Web Vitals
- Profiling (DevTools, React Profiler)
Accessibility
- WCAG 2.2 AA
- Keyboard & focus management
- ARIA
Design Collaboration
- Figma
- Design-to-development handoff
Demos
Interactive experiments with frontend techniques.
List virtualization
The same 100,000-color list rendered two ways: every row mounted, or only the rows in view. Switch between them and feel the difference.
Web Workers
Build a palette from 100,000 colors on the main thread or in a Web Worker. One freezes the page; the other keeps it smooth.
Design system
The buttons, toggles and tags this site is built from, with live examples and where each one is used.
Contact
Email is the best way to reach me, but I'm on LinkedIn too.