Jinelle Baterna

Frontend Engineer

Frontend Engineer with 7+ years building production React applications. At Mosaic Manufacturing, took on senior-level responsibilities beyond the official title, owning frontend architecture, driving technical decisions, and running the release process end to end. Cut render times 40%, reduced code duplication 30 to 40%, and dropped production bugs 20%, while owning testing across Jest, React Testing Library, and Playwright, and working closely with backend, design, QA, and product.

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Contact Info

Skills

Languages

  • JavaScript
  • TypeScript
  • HTML
  • CSS
  • Sass

Architecture & Patterns

  • Component-driven architecture
  • Design systems
  • Reusable component libraries
  • State management
  • REST API integration

Testing

  • Jest
  • React Testing Library
  • Playwright

Frameworks & Libraries

  • React
  • Redux
  • TanStack Query
  • Styled Components
  • Tailwind CSS
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Performance

  • Render optimization
  • Memoization
  • List virtualization
  • Code splitting
  • Profiling (Chrome DevTools, React Profiler)

Design Collaboration

  • Figma
  • Design-to-development handoff
  • Sketch
  • Zeplin

Work Experience

Mosaic Manufacturing Ltd

Frontend Developer | May 2021

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.
  • Proposed a feature-flag merge strategy to fix recurring merge conflicts, addressing leadership's risk concerns and cutting hotfixes and re-test cycles.
  • Managed the end-to-end release process, encompassing branch cuts, QA validation, and hotfix coordination. In the absence of existing documentation, authored a comprehensive guide to support future ownership of the process.
  • Diagnosed and resolved rendering performance issues on hardware-constrained, embedded device browsers using Chrome DevTools and React Profiler, achieving 40% faster render times.
  • Traced a tricky timing bug to inconsistent data-fetching patterns and refactored the data layer into a single retrieval path. Also worked with backend engineers on API contract design up front.

Mrkdwn, Inc.

Frontend / UX Engineer | Jan 2018 to Mar 2020

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.

Seer Technologies Inc.

Project Manager | Feb 2013 to Dec 2017

  • Managed 5 to 10 concurrent technical projects for major Philippine banks, telcos, media outlets, and insurance companies, leading teams of 5 to 10 across engineering, product, and vendors, delivering on time and within budget.
  • Ran delivery using Agile, spending a lot of that time balancing what clients wanted against protecting the engineering team from scope creep. Client relationships were strong enough that several turned into repeat business.