Harold Peñaloza

I build fast, expressive interfaces for complex products.

Frontend Software Engineer with 5 years of React experience building B2B SaaS interfaces, complex dashboards, design-system components, and frontend testing infrastructure.

Experience

Production frontend work

Real product work across React interfaces, dashboards, design-system migrations, testing infrastructure, and code review.

Built and maintained React-based frontend features across an IoT B2B SaaS platform.

Reduced frontend test pipeline time from roughly 2 hours to 30 minutes by leading the migration from Jest to Vitest.
Led the frontend migration of the Organizations module to the internal Vulcan UI design system, delivering independently with tests and no critical production bugs.
Created and maintained reusable components for Vulcan UI, helping standardize product interfaces across the platform.
Reviewed code regularly to improve maintainability, prevent production issues, and align implementation with team standards.

ReactJavaScriptTypeScriptstyled-componentsReduxReact QueryJestVitestReact Testing LibraryCypressWebpackRspack

Selected work

Projects with proof

A small set of projects that show frontend execution, visual systems, documentation, and practical developer workflows.

Professional portfolio built as a fast, static-first site to present frontend experience, projects, and HarpeBlue's visual identity.

Built with Astro to prioritize performance, SEO, maintainability, and static deployment.
Uses HarpeBlue Signal as a real design-system dependency instead of recreating visual patterns locally.

AstroTypeScriptCSSHarpeBlue Signal

Framework-agnostic visual identity system built with CSS tokens, themes, utilities, and examples.

Creates a reusable visual foundation for HarpeBlue projects without depending on a specific frontend framework.
Includes a public playground and documentation examples using pure CSS and lightweight JavaScript tooling.

CSSDesign TokensJavaScriptGitHub Pages

Technical cheatsheet concept using HarpeBlue Signal's Terminal Lab visual style.

Explores fast lookup and readable command documentation for Linux and developer workflows.
Works as the seed for a future public cheatsheets platform.

HTMLCSSHarpeBlue SignalLinux

Skills

Frontend capabilities

Technologies and practices grouped by how they show up in real frontend work: product UI, data flows, testing, tooling, and systems.

Frontend

ReactJavaScriptTypeScriptHTMLCSSstyled-components

State and Data

ReduxContext APIReact QueryFormik

Testing

JestVitestReact Testing LibraryCypress

Tooling

WebpackRspackGitGitHubnpm

UI Systems

Design systemsResponsive UIDashboardsReusable components

Workflow

Code reviewFrontend migrationsLinuxAI-assisted development

Contact

Let's build something fast and memorable.

Open to remote Frontend Software Engineer roles focused on React, product UI, design systems, testing, and AI-assisted engineering workflows.