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
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Type: Full-time independent contractor
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Location: Remote
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Clients: US and Europe
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Rate: Competitive, based on experience
What You'll Own
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End-to-end technical ownership of a high-revenue web platform and mobile app
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Architecture design and long-term technical strategy
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Server-side rendering pipeline using Node.js, Fastify 5, and React 19
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Data layer across MySQL and BigQuery
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GCP infrastructure including Cloud Run, Cloud Build, and Global Load Balancer
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Ad-tech integrations
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Performance optimization at scale, where every millisecond counts
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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:
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Node.js with TypeScript in production
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React in a server-side rendering context
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MySQL including database design, query optimization, and ORM usage
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BigQuery for querying and managing large-scale datasets
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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
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Ad-tech industry experience including ad serving, yield optimization, and programmatic advertising
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Affiliate marketing experience, particularly with Anura and Everflow
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Cloudflare including CDN configuration, caching strategies, and Workers
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Fastify, especially Fastify 5 patterns
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Flutter for mobile app contribution
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Golang or Rust for high-performance service work
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Machine learning applied to ad-tech optimization (not LLMs or agents)
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Experience in fintech,
Benefits
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Fully remote work
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Flexible hours
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Paid vacation and sick days
Application Process:
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We do not review applications via LinkedIn DMs or email. Please apply through the application link.
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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.
