Harald is available for hire
Hire HaraldHarald Solaas
Verified Expert in Engineering
FullStack Developer
Buenos Aires, Argentina
Toptal member since July 28, 2021
Bio
Harald is a software engineer with over nine years of experience building solutions for cosmetic giants like Estee Lauder, startups, and various freelance clients. He specializes in full-stack development with expertise in a range of languages (JavaScript, CSS/HTML), libraries/APIs (React, Node.js), and frameworks (React Native, Jest, Redux). Thanks to a keen eye for detail, fluid communication skills, and the ability to work well within a team or solo, you can trust Harald to deliver.
Portfolio
Carewell Family, Inc
React, TypeScript, Next.js, HTML, CSS, JavaScript, Tailwind CSS, Figma...
Cruise
React, Node.js, TypeScript, Redux, Jest, JavaScript, Cypress, D3.js, Figma...
The Estée Lauder Companies, Inc.
JavaScript, React, MobX, TypeScript, Jest, CSS, Sass, jQuery, Front-end...
Experience
- JavaScript - 8 years
- React - 7 years
- TypeScript - 7 years
- Next.js - 5 years
- Test Automation - 5 years
- React Server Components - 4 years
- Remix - 3 years
- Technical Leadership - 2 years
Preferred Environment
MacOS, Slack, Visual Studio Code (VS Code), Git
The most amazing...
...project I've worked on was for Estee Lauder, a React search component library used by hundreds of thousands of users a week for a worldwide eCommerce website.
Work Experience
Senior Software Engineer
2024 - 2025
Carewell Family, Inc
- Rebuilt a $21 million healthcare eCommerce platform alongside a 4-engineer team, migrating to a modern stack of React, Next.js, Tailwind CSS, and GraphQL while shipping on schedule.
- Achieved a Lighthouse performance score of 100, with the storefront loading instantly and remaining fully functional without client-side JavaScript via SSR and progressive enhancement.
- Delivered measurable business impact post-launch, including higher user engagement and increased sales versus the legacy platform.
- Drove exceptional SEO outcomes by architecting server-rendered pages, semantic markup, and performance budgets aligned to Core Web Vitals.
- Built reusable, accessible UI components that streamlined product discovery and checkout for family caregivers — a high-stakes, time-pressured audience purchasing home health supplies.
- Served as the bridge between engineering and product, translating user research and business goals into technical decisions across the rebuild.
- Modernized the front-end architecture (monolith to headless, component-driven) so that future feature work could ship faster and with fewer regressions.
Technologies: React, TypeScript, Next.js, HTML, CSS, JavaScript, Tailwind CSS, Figma, Storybook, Tailwind UI, Contentful, Algolia
Senior Software Engineer
2021 - 2023
Cruise
- Designed and developed a self-served analytics system that helped the data science team communicate key metrics across the company, used by top ranking executives to operations staff.
- Implemented front-end testing best practices to improve application reliability. Code coverage increased from around 20% to around 70% in three months, and reported application crashes dropped from an average of 14 a month to 0.3 a month during that time period.
- Improved the team's developer experience by introducing mocked servers and E2E testing. This allowed us to bypass the lengthy process of booting up several dependent services while keeping high reliability in the development process.
- Optimized performance of several components for a map-based view to enable the development of new features that needed to manipulate big sets of data on the client. Reduced execution time by 90%.
Technologies: React, Node.js, TypeScript, Redux, Jest, JavaScript, Cypress, D3.js, Figma, Styled-components, React Redux, HTML5, Data Visualization, Mapbox, Test Automation, Full-stack, API Integration, Architecture, Software Architecture, REST APIs, Technical Leadership, MacOS, MERN Stack, Amazon Web Services (AWS), CI/CD Pipelines, Consumer-facing Products, Modern JavaScript, Refactoring, Web Application Architecture, Page Speed Optimization
Senior Front-end Engineer
2020 - 2021
The Estée Lauder Companies, Inc.
- Developed and maintained features for a company-wide React component library used in over 200 eCommerce websites with thousands of daily customers.
- Implemented several features like a multi-type search to allow brands to engage users through articles and videos about the site's products.
- Collaborated with other teams, as part of a larger family of internal company libraries, to improve the search experience and code performance by reducing the time to first interaction with our repository.
- Achieved code reusability by building flexible components that focus on facilitating the end client's path to purchase while allowing each of the sites consuming them to customize its styles to fit their own UX.
- Brought the project's test code coverage from approximately 60% to ~85%.
Technologies: JavaScript, React, MobX, TypeScript, Jest, CSS, Sass, jQuery, Front-end, Testing, ECMAScript (ES6), Full-stack Development, Front-end Development, REST, Asynchronous Programming, SQL, Figma, Mobile-first Design, HTML5, Test Automation, REST APIs, Responsive Web Design (RWD), MacOS, MERN Stack, CI/CD Pipelines, Consumer-facing Products, Modern JavaScript, Refactoring, Web Application Architecture, Page Speed Optimization
Technical Lead
2019 - 2020
Litebox
- Developed the UI for a major Latin-American PayPal-based digital wallet with 50,000+ registered users at the time of the release. The app allows users to manage their funds, international transfers, withdrawals, and credit card expenses.
- Led the front- and back-end development of a business intelligence web application startup that helps businesses improve their revenue by analyzing the client ratio and synthesizing public data into high-value insights.
- Oversaw and took part in the development of a family of mobile applications for managing marine businesses, including cash flow, reservations, technical support, CRM, and inventory.
- Mentored team members through workshops and one-on-one coaching to help them scale from junior to mid-level React developers.
- Developed a gaming mobile application based on a popular Argentinian card game with 50,000+ downloads using React Native.
- Built a RESTful API for a local magazine that provides on-demand interactive content based on readers' interests and previous interactions. This helped the company convert its readers into donating partners.
- Led the development of a tailored eCommerce site that provided personalized nutrition for dogs; drawing upon information provided by dog owners, we would calculate the best shipping rate and recipes for each pet.
- Provided production support to several critical production releases.
- Implemented integrations using API services like Close.io, Auth0, Outseta, Contentful, and Shopify.
Technologies: JavaScript, React, React Native, Vue, Node.js, Express.js, MySQL, Docker, CSS, HTML, TypeScript, GraphQL, REST APIs, Next.js, Front-end, Testing, ECMAScript (ES6), Full-stack Development, Front-end Development, REST, Asynchronous Programming, SQL, Figma, Styled-components, React Redux, Mobile-first Design, HTML5, Data Visualization, Redux, Test Automation, Full-stack, API Integration, Architecture, Software Architecture, Material UI, Technical Leadership, Mobile, PostgreSQL, Responsive Web Design (RWD), MacOS, MERN Stack, Amazon Web Services (AWS), CI/CD Pipelines, Consumer-facing Products, Modern JavaScript, Refactoring, Web Application Architecture, Vercel
Software Engineer | Project Manager
2018 - 2019
Guru Developers
- Designed, developed, and maintained a custom wholesale eCommerce site for a top company in the local lighting industry.
- Created a streaming platform for The Art of Living Foundation with thousands of monthly users and improved engagement by presenting a number of video series (in the format of challenges) and limiting certain types of content to higher-ranking users.
- Built a family of WordPress eCommerce plugins that allow site managers to provide different prices and catalogs depending on the client's region and whether it is a wholesale store, a retail store, or a consumer.
- Negotiated contracts and ensured the delivery of services within deadlines.
Technologies: JavaScript, React, Node.js, PHP, MySQL, CSS, Sass, WordPress API, Apache HTTP Server, Front-end, Testing, ECMAScript (ES6), Full-stack Development, Front-end Development, REST, Asynchronous Programming, SQL, Figma, Styled-components, React Redux, Mobile-first Design, HTML5, Redux, Test Automation, Full-stack, API Integration, Architecture, Software Architecture, REST APIs, Material UI, Mobile, Laravel, PostgreSQL, Responsive Web Design (RWD), MacOS, MERN Stack, CI/CD Pipelines, Consumer-facing Products, Modern JavaScript, Refactoring, Web Application Architecture
Freelance Web Developer
2016 - 2018
Self-employed
- Developed the back and front ends of personal websites for artists to upload and display their artwork; also built professional portfolios for management consultants to promote their services.
- Built a marketing site for a local foundation to facilitate community engagement and convert followers into donors; achieved this by building a site that allows the post creation and ensured that the events are displayed on the website.
- Created a WordPress-based marketing and eCommerce site for a clothing retail company.
Technologies: React, Redux, TypeScript, JavaScript, HTML, CSS, Sass, Node.js, PHP, Laravel, MySQL, PostgreSQL, MongoDB, Next.js, Front-end, Testing, ECMAScript (ES6), Tailwind CSS, Auth0, Full-stack Development, Front-end Development, REST, Asynchronous Programming, SQL, Figma, PWA, Progressive Web Applications (PWAs), Styled-components, React Redux, Mobile-first Design, HTML5, Data Visualization, Full-stack, API Integration, Architecture, Software Architecture, REST APIs, Material UI, Mobile, Responsive Web Design (RWD), React Server Components, MacOS, AI Tools, Claude, CI/CD Pipelines, Consumer-facing Products, Modern JavaScript, Refactoring, Page Speed Optimization, Vercel, Claude Code
Experience
Search Component Library at Estée Lauder
An internal React component library that serves search features to over 200 eCommerce websites with thousands of daily customers around the world.
I worked as a front-end developer and was in charge of building and maintaining flexible components that could adapt to numerous design styles and use cases. Our team provided several toggles and customization features for consumers of the library to create their own unique user experiences based on a common company infrastructure.
I worked as a front-end developer and was in charge of building and maintaining flexible components that could adapt to numerous design styles and use cases. Our team provided several toggles and customization features for consumers of the library to create their own unique user experiences based on a common company infrastructure.
Management Platform for Marine Businesses at Litebox
A family of React Native mobile applications meant to provide all the functionalities of 360 management software on the user's smartphone. The main part of the project was the manager app where marina owners could receive payments and administer reservations, their statuses, related services, charges, refunds, client agenda, piers, boats, and so on.
We also built sister apps so that the marina and third-party technicians could provide additional boat services and workers could manage the company’s inventory. Beyond being part of the development team as a React Native developer, I served as the point of contact for the client—helping decide the features to deliver every month.
We also built sister apps so that the marina and third-party technicians could provide additional boat services and workers could manage the company’s inventory. Beyond being part of the development team as a React Native developer, I served as the point of contact for the client—helping decide the features to deliver every month.
Personal Website
http://www.harisolaas.comA React application built using Next.js for presentational purposes.
I built the project from the ground using TypeScript. The site displays WebGL animations built with Pixi.js and decorative illustrations of Argentinian autochthonous (indigenous) fauna.
I built the project from the ground using TypeScript. The site displays WebGL animations built with Pixi.js and decorative illustrations of Argentinian autochthonous (indigenous) fauna.
Education
2014 - 2017
Bachelor's Degree in Business Administration
University of Belgrano - Buenos Aires, Argentina
Certifications
JUNE 2021 - PRESENT
Certified Epic React Developer
Epic React by Kent C. Dodds (Epicreact.dev)
MAY 2017 - PRESENT
Web Full-stack Programming
Digital House
Skills
Libraries/APIs
React, REST APIs, React Redux, Node.js, WordPress API, Vue, MobX, jQuery, D3.js
Tools
Git, Figma, Claude, Claude Code, Slack, Apache HTTP Server, Auth0
Languages
JavaScript, CSS, HTML, TypeScript, ECMAScript (ES6), HTML5, Modern JavaScript, PHP, Sass, SQL, GraphQL
Frameworks
Redux, Next.js, React Native, Jest, Laravel, Tailwind CSS, Cypress, Material UI, Remix, Express.js, PixiJS, NestJS
Paradigms
Testing, REST, Asynchronous Programming, Test Automation, Responsive Web Design (RWD), Refactoring, Web Application Architecture
Platforms
MacOS, Visual Studio Code (VS Code), Vercel, Mapbox, Mobile, Docker, Amazon Web Services (AWS), Contentful, Algolia
Storage
PostgreSQL, MongoDB, MySQL
Other
Front-end, Full-stack Development, Front-end Development, Styled-components, Mobile-first Design, Full-stack, MERN Stack, AI Tools, Consumer-facing Products, Page Speed Optimization, PWA, Progressive Web Applications (PWAs), Data Visualization, API Integration, Architecture, Software Architecture, Technical Leadership, React Server Components, CI/CD Pipelines, Storybook, Tailwind UI
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