About this Principal Software Engineer role at pubGENIUS

pubGENIUS · Remote · Portugal

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 Defi, fintech, healthcare, and education with occasional work in e-commerce and other verticals.

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.

We are looking for a Principal Software Engineer to be the technical authority, responsible for all development, architecture decisions, and long-term technical strategy across our website, mobile app, and ML-powered ad-tech optimization systems. This is a hands-on senior role 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.

Engagement Details

Type: Full-time independent contractor
Location: Remote
Clients: US and Europe
Rate: Competitive, based on experience

What You'll Own

End-to-end technical ownership of a high-revenue web platform and mobile app
Architecture design and long-term technical strategy
Server-side rendering pipeline using Node.js, Fastify 5, and React 19
Data layer across MySQL and BigQuery
GCP infrastructure including Cloud Run, Cloud Build, and Global Load Balancer
Ad-tech integrations
Performance optimization at scale, where every millisecond counts
ML pipeline maintenance and optimization for ad-tech performance

Requirements

Must-Have Qualifications

These are non-negotiable. Please only apply if you have strong, production-proven experience in all of the following:

Node.js with TypeScript in production
React in a server-side rendering context
MySQL including database design, query optimization, and ORM usage
BigQuery for querying and managing large-scale datasets
GCP with hands-on experience in Cloud Run, Cloud Build, Cloud SQL, and Load Balancing (GCP certification is a significant bonus)

Nice-to-Have Experience

Ad-tech industry experience including ad serving, yield optimization, and programmatic advertising
Affiliate marketing experience, particularly with Anura and Everflow
Cloudflare including CDN configuration, caching strategies, and Workers
Fastify, especially Fastify 5 patterns
Flutter for mobile app contribution
Golang or Rust for high-performance service work
Machine learning applied to ad-tech optimization (not LLMs or agents)
Experience in fintech,

Benefits

Fully remote work
Flexible hours
Paid vacation and sick days

Application Process:

We do not review applications via LinkedIn DMs or email. Please apply through the application link.
We do not work with staffing agencies or third-party recruiters. Direct applicants only.

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.

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About pubGENIUS

pubGENIUS is a US-based software development agency and Ad Tech startup founded by an ex-Microsoft engineer, leading a team of Software Engineers spread across the globe. Our talents come from places like Europe, Asia, and Africa, and right back to the US. Our team was selected from the top 1 in 1,200 candidates who bring global expertise. Since 2018, we’ve worked on over 80 projects and even helped startups raise USD 15 Million in funding.

What We Do Best:

🖥 Web Development: We love creating SaaS platforms, online stores, e-learning sites, collaboration platforms, CRMs, fintech solutions, and healthcare apps.

📱Mobile App Development: We build mobile apps that look and perform great on iOS and Android and allow you to release your product faster.

🤘Fractional CTO Services:

Our fractional CTO service provides expert guidance in decision-making, selecting the ideal tech stacks, and designing great architectures. All this, without the expense of a full-time executive.

Our Tech Stack:

🪄 Web development: React, TypeScript, Javascript, NodeJS, tailwind, Jotai, NextJS

🪄Mobile App Development: React Native for mobile (Android and iOS), including working with and patching native code.

Why You'll Love Working with Us:

🌍 A Global Team That Gets You: Our team is everywhere, so we’re 24/7 on and understand what you need, no matter where you are.

🚀 MVP Masters: Got a startup idea? We're experts in turning early-stage projects into ready-to-launch products.

🏢 Enterprise Excellence: Not just for startups or MVPs, we also partner with established enterprises. Our team is adept at handling complex, large-scale projects, offering tailored solutions at an enterprise level.

🔮 Quality Is Our Promise: We're not just about meeting deadlines. We’re about delivering fast, top-notch, and reliable work that drives business growth. At pubGENIUS, it doesn't matter if you're just starting or a large enterprise in your field – our team is here to turn your digital dreams into reality🚀💡

🔎 Find Us By: User Experience, Web Development, Mobile App Design, SaaS, FinTech, Healthcare, e-learning, Blockchain, User Interface, React Native, NodeJS, Cross-Platform Apps, Strategic Tech Leadership, Global Software Solutions.