Fractional Senior Full Stack Engineer (Stabilization / AI-Generated Code)

This position is posted by Jobgether on behalf of a partner company. We are currently looking for a Fractional Senior Full Stack Engineer (Stabilization / AI-Generated Code) in Brazil.

This role is designed for a highly experienced engineer who thrives in fast-moving, early-stage product environments where code quality and structure need immediate stabilization.
You will work across multiple products that were rapidly built using AI tools or non-technical founders, often resulting in fragile or inconsistent architectures.
Your mission is to bring clarity, reliability, and production readiness to these systems through hands-on engineering work.
The role is fractional and flexible, allowing you to contribute across several projects based on priority and impact.
You will operate in a dynamic environment where requirements evolve quickly and autonomy is essential.
This position is ideal for someone who enjoys untangling complex systems and turning unstable MVPs into scalable, maintainable products.
Your work will directly improve system stability, performance, and long-term product viability.

Accountabilities:

• Review and analyze existing codebases, often built with AI tools or minimal technical oversight, to identify structural issues, bugs, and risks.
• Refactor and stabilize applications to ensure they are production-ready, maintainable, and scalable across different environments.
• Improve system performance, backend logic, and overall architecture, ensuring consistency and reliability.
• Fill critical gaps in core functionality such as authentication, payments, APIs, and backend services.
• Implement lightweight testing and QA practices to improve code quality and reduce regression risks.
• Collaborate closely with engineers, QA, and product stakeholders to align technical fixes with business priorities.
• Work across multiple concurrent projects, adapting quickly to shifting priorities and evolving requirements.
• Contribute to improving engineering standards and introducing practical, scalable solutions in fast-paced environments.

Requirements:

• 5+ years of full stack engineering experience in production environments.
• Strong track record of working with messy, inherited, or rapidly built codebases.
• Ability to operate independently with limited documentation or technical specifications.
• Proven experience taking MVP-stage products to stable, production-grade systems.
• Strong proficiency in modern full stack technologies such as Python (FastAPI or Django), Node.js, TypeScript, and React or Next.js.
• Experience working with APIs, modern web architectures, and backend systems.
• Familiarity with Firebase, Supabase, or similar backend-as-a-service tools is a plus.
• Strong problem-solving mindset with a focus on practical, high-impact engineering solutions.
• Excellent communication and collaboration skills in fast-paced, delivery-driven teams.
• Flexibility to adapt across different codebases, stacks, and project contexts.

Benefits:

• Flexible fractional engagement ranging from 10 to 40 hours per week depending on project demand.
• Remote work setup with collaboration across distributed, international teams.
• Opportunity to work on multiple early-stage products and diverse technical challenges.
• High-impact role focused on stabilizing and improving real-world production systems.
• Initial short-term engagements (around 4 weeks) with potential for ongoing project extensions.
• Exposure to modern, AI-influenced development environments and evolving tech stacks.

How Jobgether works: We use an AI-powered matching process to ensure your application is reviewed quickly, objectively, and fairly against the role's core requirements. Our system identifies the top-fitting candidates, and this shortlist is then shared directly with the hiring company. The final decision and next steps (interviews, assessments) are managed by their internal team. We appreciate your interest and wish you the best!  Why Apply Through Jobgether?    Data Privacy Notice: By submitting your application, you acknowledge that Jobgether will process your personal data to evaluate your candidacy and share relevant information with the hiring employer. This processing is based on legitimate interest and pre-contractual measures under applicable data protection laws (including GDPR). You may exercise your rights (access, rectification, erasure, objection) at any time.     #LI-CL1