Principal Software Engineer (React + Node) - Remote -EU or USA

Other Jobs To Apply

pubGENIUS is a React.js and Next.js development agency and ad-tech startup. We build websites and apps for clients across the US and Europe, specializing in decentralized finance (DeFi, crypto, NFT, blockchain), fintech, and healthcare, with occasional work in e-commerce and other verticals.<br><br>Beyond client work, we operate our own high-revenue web product with a website, mobile app, and machine learning systems powering our ad-tech optimization engine. Performance is not a preference here, it is a core requirement.<br><br>We are looking for a<strong> Principal Software Engineer, </strong>who will be the technical authority, responsible for all development, architecture decisions, and long-term technical strategy across a website, mobile app, and ML-powered ad-tech optimization systems.<br><br>This is a full-time independent contractor engagement. You will work hands-on at a senior level where site speed and server performance are core success metrics. You will work directly with stakeholders to set technical direction, remove bottlenecks, and ship production-grade code.<br><br><strong>Engagement Details:<br><br></strong><ul><li>Type: Full-time independent contractor or EOR</li><li>Hours: Full-time commitment expected</li><li>Location: Remote </li><li>Clients: US and Europe</li><li>Rate: Competitive, based on experience<br><br></li></ul><strong>What You'll Own<br><br></strong><ul><li>End-to-end technical ownership of a high-revenue web platform and mobile app</li><li>Architecture design and long-term technical strategy</li><li>Server-side rendering pipeline using Node.js, Fastify 5, and React 19</li><li>Data layer across MySQL and BigQuery</li><li>GCP infrastructure including Cloud Run, Cloud Build, and Global Load Balancer</li><li>Ad-tech integrations including Google Ad Manager, GTM, GTag, and GPT.js</li><li>Performance optimization at scale, where every millisecond counts</li><li>ML pipeline maintenance and optimization for ad-tech performance<br><br></li></ul><strong>Requirements<br><br></strong><strong>Must-Have Qualifications<br><br></strong>These are non-negotiable. Please only apply if you have strong, production-proven experience in all of the following:<br><br><ul><li>Node.js with TypeScript in production</li><li>React in a server-side rendering context</li><li>MySQL including database design, query optimization, and ORM usage</li><li>BigQuery for querying and managing large-scale datasets</li><li>GCP with hands-on experience in Cloud Run, Cloud Build, Cloud SQL, and Load Balancing. GCP certification is a significant bonus<br><br></li></ul><strong>Nice-to-Have Experience<br><br></strong><ul><li>Ad-tech industry experience including ad serving, yield optimization, and programmatic advertising</li><li>Affiliate marketing experience, particularly with Anura and Everflow</li><li>Cloudflare including CDN configuration, caching strategies, and Workers</li><li>Fastify, especially Fastify 5 patterns</li><li>Flutter for mobile app contribution</li><li>Golang or Rust for high-performance service work</li><li>Machine learning applied to ad-tech optimization (not LLMs or agents)</li><li>Experience in DeFi, crypto, NFT, blockchain, fintech, or healthcare verticals<br><br></li></ul><strong>Benefits<br><br></strong><ul><li>Fully remote work</li><li>Flexible hours</li><li>Paid vacation and sick days<br><br></li></ul><strong>Application Process<br><br></strong><ul><li>We do not review applications via LinkedIn DMs or email. Please apply through the application link</li><li>We do not work with staffing agencies or third-party recruiters. Direct applicants only<br><br></li></ul>pubGENIUS is an Equal Opportunity Employer; employment with pubGENIUS is governed on the basis of merit, competence, and qualifications and will not be influenced in any manner by race, age, colour, gender, religion, national origin/ethnicity, veteran status, sexual orientation, marital status, gender identity, mental or physical disability, or any other legally protected status.

Back to blog

Common Interview Questions And Answers

1. HOW DO YOU PLAN YOUR DAY?

This is what this question poses: When do you focus and start working seriously? What are the hours you work optimally? Are you a night owl? A morning bird? Remote teams can be made up of people working on different shifts and around the world, so you won't necessarily be stuck in the 9-5 schedule if it's not for you...

2. HOW DO YOU USE THE DIFFERENT COMMUNICATION TOOLS IN DIFFERENT SITUATIONS?

When you're working on a remote team, there's no way to chat in the hallway between meetings or catch up on the latest project during an office carpool. Therefore, virtual communication will be absolutely essential to get your work done...

3. WHAT IS "WORKING REMOTE" REALLY FOR YOU?

Many people want to work remotely because of the flexibility it allows. You can work anywhere and at any time of the day...

4. WHAT DO YOU NEED IN YOUR PHYSICAL WORKSPACE TO SUCCEED IN YOUR WORK?

With this question, companies are looking to see what equipment they may need to provide you with and to verify how aware you are of what remote working could mean for you physically and logistically...

5. HOW DO YOU PROCESS INFORMATION?

Several years ago, I was working in a team to plan a big event. My supervisor made us all work as a team before the big day. One of our activities has been to find out how each of us processes information...

6. HOW DO YOU MANAGE THE CALENDAR AND THE PROGRAM? WHICH APPLICATIONS / SYSTEM DO YOU USE?

Or you may receive even more specific questions, such as: What's on your calendar? Do you plan blocks of time to do certain types of work? Do you have an open calendar that everyone can see?...

7. HOW DO YOU ORGANIZE FILES, LINKS, AND TABS ON YOUR COMPUTER?

Just like your schedule, how you track files and other information is very important. After all, everything is digital!...

8. HOW TO PRIORITIZE WORK?

The day I watched Marie Forleo's film separating the important from the urgent, my life changed. Not all remote jobs start fast, but most of them are...

9. HOW DO YOU PREPARE FOR A MEETING AND PREPARE A MEETING? WHAT DO YOU SEE HAPPENING DURING THE MEETING?

Just as communication is essential when working remotely, so is organization. Because you won't have those opportunities in the elevator or a casual conversation in the lunchroom, you should take advantage of the little time you have in a video or phone conference...

10. HOW DO YOU USE TECHNOLOGY ON A DAILY BASIS, IN YOUR WORK AND FOR YOUR PLEASURE?

This is a great question because it shows your comfort level with technology, which is very important for a remote worker because you will be working with technology over time...