Senior Full Stack Developer

About the Position

We are looking for a Senior Full Stack Developer to build and maintain backend services and frontend interfaces that surface, validate, and resolve issues in data coming from ETL pipelines, data lake outputs, and ML model results for a large-scale marketing analytics platform. You will develop REST APIs in Python using FastAPI or Flask, build responsive React and TypeScript frontends, manage PostgreSQL schemas and migrations, and leverage AI-assisted development tools with the critical judgment to push back on shortcuts that compromise long-term maintainability.

Responsibilities

• Build and maintain scalable backend services (REST APIs) and responsive frontend interfaces using React and TypeScript.
• Build the interfaces and services that surface, validate, and resolve issues in data coming from the data lake, ETL pipelines, health-check logic, or model outputs - without necessarily owning pipeline architecture.
• Package and manage applications using Docker.
• Use AI-assisted development tools (e.g., Claude Code) to move fast during implementation - while critically evaluating AI-generated output and pushing back when it isn't the right long-term solution.
• Drive conversations directly with client engineers to clarify both functional and non-functional requirements, rather than defaulting to whatever "just works" in the short term.
• Work daily with client engineers through Slack and Google Meet.

Requirements

• 5–7 years of full-stack software development experience.
• Strong proficiency in Python (FastAPI or Flask) and TypeScript/React.
• Solid understanding of relational databases, including PostgreSQL and database migrations.
• Comfortable working with REST APIs and migrating away from legacy GraphQL when needed.
• Demonstrated experience building or maintaining data-heavy applications with large datasets and performance-sensitive queries at the application layer.
• Practical, hands-on use of AI-assisted development tools, paired with the critical judgment to challenge AI output when it compromises long-term maintainability.
• High comfort level working in a Mac/Linux terminal environment, including Bash and Makefiles.
• Strong soft skills (mandatory, not a bonus): the ability to hold and defend a technical opinion - challenging a stakeholder's or a tool's proposed "quick fix" with sound reasoning in pursuit of a solution that scales and is maintainable long-term, while still being pragmatic enough to ship.
• Upper-intermediate English level.

Nice to Have

• Exposure to object-storage-backed data lakes and serverless query engines such as S3 + Athena or comparable technologies (Trino/Presto, BigQuery, Spark SQL).
• Familiarity with DAG-based task orchestration (Airflow, Dagster, Prefect, Step Functions), or the ability to pick it up quickly.
• Data engineering exposure - experience building or maintaining ETL pipelines, advanced SQL (complex queries, data validation, optimization).
• Experience with caching or NoSQL systems such as Redis or DynamoDB.
• Experience with monorepo tooling or modern package managers such as Nx, Poetry, or UV.
• Familiarity with AWS Bedrock or similar AI/LLM SDKs.
• Experience with marketing data structures, campaign management APIs, or digital advertising metrics.

We Offer

• Growth without limits: build your skills through mentorship, internal TechTalks, challenging projects, and a dedicated annual learning budget.
• Competitive compensation: get recognition that reflects your skills and impact, with regular performance and compensation reviews.
• Flexibility: work 100% remotely with flexible hours that support focus, autonomy, and a healthy work rhythm.
• Meaningful, modern projects: build impactful products using modern technologies alongside global teams and leading brands.
• Collaborative culture: join a supportive environment with zero micromanagement where ideas are welcomed and contributions are recognized.
• Well-being & support: access local well-being programs and people-focused support tailored to your location.

About the Company

At Kepler Group, we are committed to building innovative solutions that drive success for our clients. Our team is composed of passionate professionals who thrive in a collaborative and dynamic environment. We value creativity, continuous learning, and the pursuit of excellence in everything we do.