Senior Full-Stack Developer - Python, AI & React
First seen by Alion on Aug 5, 2026.
Unleash innovation at scale - shape the future of AI-driven financial platforms.
Location & Work Model: Remote-based opportunity with flexibility to work from Poland or Portugal, up to 5 days per week.
As a Senior Full-Stack Developer, you will be working for our client, a leader in capital markets technology, delivering cutting-edge AI and web solutions. You will build and maintain high-performance applications that integrate modern React front ends with Python back ends, empowered with AI/LLM features to revolutionize financial data processing and decision-making. Join us and contribute to shaping innovative financial ecosystems.
Your main responsibilities:
Design and develop end-to-end features, including React/Next.js interfaces and Python back-end services and APIs.
Implement, maintain, and optimize AI/LLM-powered functionalities such as RAG pipelines, agentic workflows, and API integrations.
Build responsive, accessible user interfaces from design specifications to production deployment.
Write clean, well-tested, and maintainable code across both front-end and back-end layers.
Design and implement REST/GraphQL APIs and data models for complex financial and market data.
Collaborate with cross-functional teams including designers, data/ML engineers, and product managers to deliver features end-to-end.
Optimize applications for performance, scalability, security, and cross-browser compatibility.
Participate in code reviews and contribute to engineering standards and best practices.
Leverage AI-assisted development tools to accelerate delivery and enhance code quality.
You're ideal for this role if you have:
Minimum of 6 years of experience in full-stack development, with a focus on Python and JavaScript.
Strong expertise in React, TypeScript, and modern JavaScript (ES6+).
Proven experience with back-end frameworks such as FastAPI, Django, or Flask.
Solid understanding of REST API design, asynchronous data handling, and front-end best practices.
Familiarity with HTML5, CSS3, and responsive UI design.
Knowledge of relational and NoSQL databases like PostgreSQL and MongoDB.
Strong grasp of Git and collaborative development workflows.
Good understanding of web security, performance, and accessibility fundamentals.
It is a strong plus if you have:
Production experience with Next.js (SSR, SSG, API routes).
Hands-on experience building or integrating AI/LLM features (e.g., prompt engineering, vector databases, LangChain, LlamaIndex).
Experience working with Claude and other AI solutions.
Familiarity with state management libraries (Redux, React Query, etc.).
Knowledge of CSS frameworks like Tailwind or styled-components.
Experience with cloud deployment, infrastructure (AWS, GCP), Docker, and CI/CD pipelines.
Testing expertise with Pytest, Jest, React Testing Library, or Cypress.
Language Required for the role:
Fluent command of English.
Eligibility to work on this role:
Only candidates with an existing legal right to work in the European Union will be considered.
#MAKEYourCareerBETTER
Interested? Apply now and include your CV (preferably in English), along with a statement confirming your consent to the processing and storage of your personal data.