Andreas Groos, Developer in Nevada City, CA, United States
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Andreas Groos

Verified Expert  in Engineering

Full-stack Developer

Nevada City, CA, United States
Toptal Member Since
July 19, 2021

Andreas is a full-stack developer specializing in front-end development with multiple libraries and frameworks, including React, Vue.js, and Next.js, and their associated technologies. With experience in freelance and enterprise environments and a passion for quality code and good UX, Andreas has what it takes to advance projects quickly and deliver exceptional products.


JavaScript, TypeScript, Node.js, Express.js, Firebase, Contentful, Gatsby...
JavaScript, React, Redux, Semantic UI, Sass, Node.js, MongoDB, APIs
Landslide 2020
JavaScript, Next.js, Firebase, CSS




Preferred Environment

Ubuntu, Skype, Slack, Zoom

The most amazing...

...project I've done was building, from scratch, the enterprise console for a zero trust, passwordless authentication startup.

Work Experience

Full-stack Developer

2017 - PRESENT
  • Implemented a petition website (front and back end), with the integration of several external APIs, backed by a Firebase back end and PayPal payment portal.
  • Created a website to display science data, using maps and data visualization by consuming a GraphQL back end. This was built in Vue.js with Leaflet maps and Highcharts for data visualization.
  • Built several other front ends, mostly in React and Vue.js with some WordPress.
Technologies: JavaScript, TypeScript, Node.js, Express.js, Firebase, Contentful, Gatsby, GraphQL, APIs, Vue, Leaflet, Highcharts, React, CSS

Lead Front-end Developer

2019 - 2021
  • Built a new enterprise console to administer accounts, customers, users, and other information, using various API endpoints.
  • Implemented complex forms and advanced client authentication.
  • Designed the interface starting with Semantic UI as a foundation, modifying and personalizing it to fit the company, and iterating the design to improve the UX.
  • Collaborated with the back-end team (working Node.js and MongoDB) to implement and debug the console.
Technologies: JavaScript, React, Redux, Semantic UI, Sass, Node.js, MongoDB, APIs

Lead Front-end Developer

2020 - 2020
Landslide 2020
  • Led a small team to develop a website to display relevant voting information related to COVID-19 and other relevant topics.
  • Delivered the required features within the limited time available before the election and with constantly changing requirements.
  • Performed rapid iteration based on customer requirements and A/B testing.
Technologies: JavaScript, Next.js, Firebase, CSS

RiverDB (Database)
A Sass project for an environmental organization focused on rivers. The cloud-based database and website track and display river science data and make it easily available to the public. The database includes a GraphQL back end and a data entry portal, which is not accessible to the public. It uses mapping and graphing technologies.

An interactive website to calculate and display the watershed for any point in the lower 48, including river flow information, reservoir storage, and more. I created the website by using several public data sources, such as USGS and EPA, that have poor front-end implementations. Unfortunately, the main USGS API performance got degraded, resulting in longer wait times for some calculations.

A full-stack application to enable people to quickly and easily send physical postcards to their representatives in Washington, D.C. After entering an address, it pulls the current representatives from Google's Civic API and then interacts with other APIs to send emails and the physical postcards with custom artwork. At the same time, there is a small donation to an NGO connected with the cause.


Sass, CSS, JavaScript, GraphQL, TypeScript


Redux, Next.js, Express.js


React, Leaflet, Node.js, Vue, Vuex, PayPal API, Highcharts, Google Civic API, REST APIs




Ubuntu, Firebase, Contentful, Amazon Web Services (AWS)


MongoDB, Google Cloud


Semantic UI, Gatsby, APIs, Servers

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