# Principal Software Engineer

> pubGENIUS · Brazil (Remote) · Full-time · Posted 2026-06-12

**Workplace:** remote

**Department:** Engineering

## 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 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 t**o 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.

## Apply

[Apply at pubGENIUS](https://apply.workable.com/pubgenius-1/j/EB40CD71AB/apply)

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