Principal Software Engineer

Description

Summary: pubGENIUS is seeking a Principal Software Engineer to be the technical authority for development, architecture, and strategy across web, mobile, and ML-powered ad-tech systems. Highlights: 1. Technical authority for development, architecture, and long-term strategy 2. End-to-end technical ownership of high-revenue web platform and mobile app 3. Work hands-on at a senior level, setting technical direction and shipping code 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 **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 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.