Job Description

**Description**
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.

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, 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.

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.

**Engagement Details:**

Type: Full-time independent contractor
Hours: Full-time commitment expected
Location: Remote (US, Canada, UK, Ireland or Netherlands)
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 including Google Ad Manager, GTM, GTag, and GPT.js
* Performance optimization at scale, where every millisecond counts
* ML pipeline maintenance and optimization for ad-tech performance

**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 DeFi, crypto, NFT, blockchain, fintech, or healthcare verticals

**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.