Senior Fullstack Engineer

This role is open to candidates based in LATAM, Africa, and Eastern Europe. Please note that as this role supports U.S.-based clients, candidates must be available to work during U.S. business hours aligned with the client’s time zone.

Client Overview

Our client is a fast-moving marketing measurement and attribution technology company that empowers e-commerce brands to make smarter, data-driven advertising decisions. Their platform combines a robust Rails API, a modern React frontend, and a Python-powered data and ML infrastructure — all operating across a 20+ repository workspace where AI agents and engineers collaborate side by side to ship product at speed. They are a team that values engineering craft, architectural clarity, and a bias toward simplicity, and they are looking for senior engineers who raise the bar through code review, documentation, and thoughtful system design as much as through feature delivery.

Role Overview

The Senior Fullstack Engineer will own and elevate engineering quality across a multi-repo platform that spans a Rails API, React frontend, and Python data and ML services. This role sits at the intersection of backend architecture, frontend delivery, and data platform development, making it ideal for a polyglot engineer who is energized by ambiguity and cross-service complexity. The Senior Fullstack Engineer will also mentor fellow engineers, establish best practices, and help design agent-readable systems as AI-assisted development becomes a core part of how the team operates.

Location

Fully Remote (Work from Home) | 9AM - 5PM EST

Key Responsibilities

Backend Development

• Design and ship production features on theRuby on Rails API, including authentication flows, background jobs viaSidekiq, andPostgreSQL schema design.

• Maintain and improve API contracts usingOpenAPI orJSON:API standards consumed by SPA frontends.

• Write and enforce test coverage usingRSpec, maintaining high reliability across services.

Frontend Development

• Build and maintain React applications using hooks and modern state management patterns.

• Work confidently withTypeScript, modern bundlers, and JS toolchains includingBun,Vite, andesbuild.

• Contribute to and evolve a shared component library and design system.

Python & Data Platform

• Contribute to ETL pipelines,Snowflake transformations, and external API integrations.

• Work with orchestration tools such asDagster orAirflow to manage data workflows in production.

• Partner with Data Science and ML Engineering teams to productionize models into reliable, observable inference services.

Infrastructure & DevOps

• Maintain and improve container-based local development usingDocker andDocker Compose.

• Operate within anAWS environment (ECS Fargate, Lambda, EventBridge, S3) and support infrastructure managed viaTerraform.

• Own and improveCI/CD pipelines usingGitHub Actions and drive pragmatic observability across services.

Engineering Leadership & Developer Experience

• Establish and enforce engineering best practices across a 20+ repo workspace, covering testing strategy, CI/CD, observability, and code review standards.

• Improve developer experience through local dev tooling,Makefile automation, and onboarding documentation.

• Lead code reviews and PR triage; drive improvements in type safety, security, and incremental refactoring.

• Write clear specs, RFCs, and architecture docs — including agent-readable context files for AI coding agent workflows using tools likeClaude Code orCursor.

• Mentor engineers through pairing, documentation, and review rather than gatekeeping.

Qualifications — Experience

• 5+ years building productionRuby on Rails APIs (Rails 7+), with deep familiarity withActiveRecord,Sidekiq,RSpec, JWT/auth flows, andPostgreSQL schema design.

• 5+ years building productionReact applications using hooks and modern state management patterns.

• TypeScript and modern JS toolchains includingBun,Vite, andesbuild.

• ProductionPython (3.11+) experience, ideally withDagster,Airflow, or similar orchestration frameworks.

• Hands-on experience contributing toETL pipelines,Snowflake transformations, and external API integrations.

• Experience withDocker,Docker Compose, and container-based local development workflows.

• Working knowledge ofAWS services (ECS Fargate, Lambda, EventBridge, S3) and infrastructure-as-code viaTerraform.

• Experience withCI/CD pipelines usingGitHub Actions and a strong understanding of observability practices.

• Track record of writing technical specs, RFCs, or architecture documentation in a cross-team environment.

Qualifications — Skills

• Strong architectural thinking across backend, frontend, and data systems — able to spot patterns and risks across services.

• Bias toward simplicity: removes code and abstractions as readily as adding them.

• Comfortable operating autonomously in a multi-repo, fast-moving codebase alongside AI coding agents.

• Mentorship mindset — makes the team around them better through review, documentation, and pairing rather than heroic individual contribution.

• Strong opinions loosely held on testing strategy, dependency management, and incremental refactoring.

• Judgment to know when to standardize across services and when to let a service stay appropriately opinionated.

• Comfortable working in ambiguity and driving clarity through documentation and communication.

Opportunity

This is a rare opportunity for a polyglot senior engineer to have genuine architectural ownership across an entire product platform — not just one slice of the stack. You will work at the frontier of AI-assisted software development, shaping how engineers and AI agents collaborate in a production environment, while directly influencing the engineering culture and practices of a growing, technically ambitious team. The role offers a competitive base compensation of $4,000–$5,000 per month, full remote flexibility, and the chance to make a lasting mark on a platform that sits at the intersection of machine learning, marketing intelligence, and modern software engineering.

Application Process:

To be considered for this role these steps need to be followed:

• Fill in the application form

• Record a video showcasing your skill sets