Seppe van Dalen, Developer in Eindhoven, Netherlands

Seppe van Dalen

Software Developer

Eindhoven, Netherlands
Toptal Member Since
July 16, 2021

Seppe is a passionate front-end developer who is always aiming for the best user experience by leveraging the full React ecosystem. He's especially interested in B2B SaaS-related projects but also happy to code along with any B2C apps. He is a self-driven curious person with a background in tech and B2B sales and marketing. Seppe spent the last few years living abroad, working with and learning from many different people with interesting backgrounds.

Seppe is available for hire
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Node.js, React, React Redux, MongoDB, MongoDB Atlas, Mongoose...
JavaScript, HTML, CSS, Electron, Chrome Extensions, APIs, Gmail API, REST APIs
B2B, B2B Lead Generation, Account-based Marketing (ABM)


Eindhoven, Netherlands



Preferred Environment

MacOS, Linux

The most amazing...

...thing I've developed is a scalable full-stack B2B SaaS, helping sales teams across to world to close more deals.

Work Experience

2020 - PRESENT

Full-stack Developer

  • Developed SaaS for B2B sales teams to automate, organize and analyze account-based marketing for both the back end and the front end.
  • Used React, Redux, Material-UI, and Gatsby as the main front end stack, and Node.js, Express, MongoDB, and Mongoose as the back end stack.
  • Hosted a project on the Google Cloud Platform and optimized the app engine instance for scalability.
  • Built custom integrations with APIs from G Suite, Office 365, HubSpot, and Pipedrive. Also added options to integrate with SMTP and IMAP.
Technologies: Node.js, React, React Redux, MongoDB, MongoDB Atlas, Mongoose, MUI (Material UI), Gmail API, SMTP, IMAP, Google Cloud Platform (GCP), REST APIs, HubSpot, Office 365 API, Express.js, Axios, Back-end, Front-end, TypeScript, Webhooks, API Design
2019 - 2021

System Specialist

  • Developed custom tools, Chrome extensions, and a desktop application to automate and standardize business processes across offices.
  • Built automated reporting functionalities by extensive integrations of our CRM REST API.
  • Supported integrating a new ERP system (Odoo) across global offices and built custom features to facilitate business processes.
Technologies: JavaScript, HTML, CSS, Electron, Chrome Extensions, APIs, Gmail API, REST APIs
2019 - 2020

Business Development Representative

  • Performed strategic planning for new ABM campaigns by identifying and matching pain points, ideal customer profiles, and buyer personas.
  • Established relationships with key decision-makers to generate new business opportunities.
  • Conducted research to uncover potential target areas, markets, and industries. Working in regions like Benelux and North America.
Technologies: B2B, B2B Lead Generation, Account-based Marketing (ABM)


Sales Development Platform
SaaS for B2B sales teams to automate, organize and analyze account-based marketing. I developed both the back end and the front end.

Access to this project is upon request.

This was a full-stack project using mostly, but not limited to, front end technologies including React, Redux, Material-UI, Node.js, back end technologies Express, Mongoose, and MongoDB Database.

This project also involved heavy integrations with API from Google, Office 365, Hubspot, and Pipedrive. Moreover, it has an SMTP and IMAP level integration for mailbox synchronization. It is hosted in the Google Cloud Platform with a microservice architecture and many cron jobs.

The most challenging part of this project was its size; it had many different facets that needed to work together while being scalable and reliable at its core.

Native Desktop Application

A native desktop application that worked hand-in-hand with our CRM through extensive integration of APIs.

The purpose of the application was to automate and standardize business processes and reporting across offices. The application supported employees in how they work, reported to clients, and analyzed their work.

The main technologies I used in this project are Electron.js, React, Node.js, JavaScript, and CSS.

Chrome Extension

A Chrome extension to ease business processes and increase productivity across teams. The extension had data scrapping and standardizing functionalities.

The extension was built in JavaScript, HTML, and CSS. It is heavily relying on Chrome API and Chrome storage.



JavaScript, HTML5, CSS3, HTML, CSS, TypeScript


MUI (Material UI), Express.js, Redux, JSON Web Tokens (JWT), Electron


React, Node.js, REST APIs, Office API, Gmail API, React Redux, Pipedrive API, Office 365 API, React Router, Recharts, Chrome API


MongoDB, PostgreSQL


Axios, JSON REST APIs, Gatsby, HubSpot API, Front-end, Back-end, Webhooks, API Design, Chrome Extensions, SMTP, IMAP, B2B Lead Generation, Account-based Marketing (ABM), APIs, Data Visualization, HubSpot


Web UX Design, Web UI Design, B2B


MongoDB Atlas, Mongoose


Google Cloud Platform (GCP)