Senior Full-Stack Software Engineer (Python / React)

3Pillar is an AI transformation partner on a mission to help enterprises build the AI-native products and intelligent agents that will define the next era of business. With teams across North America, Europe, Latin America, and Asia, we work with the most ambitious companies in financial services, healthcare, media, and technology — helping them move faster, modernize boldly, and compete on their own terms. Our HelixAI platform and Helix Pods delivery model put our engineers at the center of real agentic transformation — doing work that is open, portable, and built to last. We are building the future of enterprise AI.

👋 Greetings, future tech savant:

Embark on an exciting journey into the realm of software development with 3Pillar! We are looking for an experienced Senior Full-Stack Engineer to drive the modernization of our core platform. We need a pragmatic, senior-level engineer, comfortable across a Python backend and a React frontend on AWS, who can tackle complex technical debt, own architectural decisions, and help us scale our cloud-based system. If you are passionate about building scalable, maintainable distributed systems and want to make a tangible impact on a product used by a global customer base, this is the role for you.

Key Responsibilities:

• Craft client code that is not just efficient but also performant, testable, scalable, secure, and of the highest quality.

• Ensure code is secure through Software Composition Analysis (SCA), and drive remediation through triaging, prioritization, remediation and verification.
• Provide accurate status tracking, reporting, and estimation using project methods and tools.
• Gather requirements, validate their understanding amongst the team, and create and maintain relevant documentation.
• Design and implement scalable AI and agentic workflows using LLMs, focusing on reliability and observability.
• Build and maintain responsive, well-tested frontend features in React alongside backend services.
• Work within an AI-driven development workflow, applying spec-driven development practices (writing clear specs/prompts that steer AI-assisted implementation) and using GitHub Copilot as a core part of the daily engineering workflow.
• Execute activities within the current methodology and uphold the highest quality standards.
• Partner directly with Product and Engineering leadership to translate complex business requirements into scalable technical solutions.
• Identify and remediate technical debt to improve system stability, performance, and developer velocity.
• Take ownership of projects, from technical design to a successful launch.
• Participating in code reviews to maintain code quality and consistency.

Minimum Qualifications:

• Extensive senior-level professional experience in software engineering, with strong depth in Python and distributed systems.

• Proven ability to own technical features from design through to production deployment with minimal supervision.
• Deep understanding of system design, architecture, and the ability to solve ambiguous technical challenges.
• Expertise with Git source control tools (Github, Gitlab or others)
• Expertise with Python package management (UV, Conda or others)
• Experience with unit testing (Pytest).
• Hands-on experience building production frontend applications in React, alongside backend services at scale.
• Experience with managing Docker containers, and orchestration with Kubernetes and AKS.
• Intermediate level design proficiency following UML / C4 / ArchiMate.
• Experience in engineering software systems of medium-to-large scope and complexity.
• Proficiency with relational databases.
• Experience deploying and operating systems on AWS.
• Working knowledge of GitHub Copilot (or similar AI coding assistant) and spec-driven development practices in an AI-assisted engineering workflow.
• Familiarity with Agile software development methodologies.
• Proficiency in the English language.

Additional Experience Desired:

• Knowledge of Python web frameworks (Flask or others)

• Knowledge of Snowflake
• Experience with Agentic frameworks (e.g., MCP, A2A)
• Knowledge of workflow orchestration platforms (Apache Airflow, Automic Automation or others)
• Knowledge of protocols like HTTP, and serialization formats like JSON and XML.
• Knowledge of SCA platforms (Github Advanced Security, Snyk, Checkmarx or others)
• Familiarity with other AI coding agents (Claude Code, Cursor, etc.) beyond Copilot.
• Proficiency in Object-Oriented Programming (inheritance, polymorphism, classes, instances, properties).