Full-Stack Developer Python, React, FastAPI – 100% Remote

Description

Summary: Seeking a Full-Stack Developer to build and enhance Python backend services and React frontends, implementing LLM integrations and working with vector databases for RAG workflows. Highlights: 1. Opportunity to build cutting-edge AI SaaS used by enterprise clients 2. Direct collaboration with founders and leadership team 3. Growth path: potential to evolve into Lead Engineer Flex is a global leader in strategic technical support and AI\-driven tools, dedicated to innovation, customer success, and teamwork. We partner with Fortune 500 companies and are growing quickly. Now, we’re looking for a Full\-Stack Developer (Python, React, FastAPI, LLM/RAG) 100% Remote As a startup, we move fast, iterate quickly, and value team members who take ownership and deliver impact. We are now scaling our engineering team to accelerate product development, improve performance, and deliver advanced AI features to enterprise clients. Responsibilities * Develop and maintain **Python backend services** (APIs, RAG pipelines, FastAPI). * Build and enhance **React\-based frontends** (dashboards, user\-facing tools). * Implement **LLM integrations** (OpenAI, Anthropic, Hugging Face) and optimize token usage. * Work with **vector databases (Qdrant, Pinecone, Weaviate)** for RAG workflows. * Design and test new features with proper **unit/integration testing**. * Write clear **technical documentation** in English. * Collaborate with leadership and Customer Success to translate client needs into technical solutions. Requirements * 2\+ years professional experience in **Python development**. * Strong knowledge of **FastAPI** (preferred). * Experience with **React (TypeScript, Tailwind)** for frontend development. * Solid background in **APIs, authentication, integrations**. (ie: OpenAI GPT\-4, Jira webhooks) * Familiarity with **vector databases (Qdrant, Pinecone, etc)** and RAG patterns. * Hands\-on experience with **LLMs** (OpenAI, Anthropic, Hugging Face, LangChain, LlamaIndex). * Experience with **PostgreSQL** and ORMs. * Proficiency with **testing frameworks (pytest, jest, etc.)**. * **English (intermediate conversational or better)** for documentation and calls. * Ability to work independently in a **startup environment**, with **ownership mindset.** * Experience deploying apps with **Docker \+ cloud (AWS, GCP, Linode, DigitalOcean)**. * **Vite** build tool, **shadcn/ui** \+ Tailwind CSS Nice to Have * Prior exposure to **customer support SaaS or enterprise systems**. * Knowledge of **MLOps** or AI model fine\-tuning. What We Offer * **100% remote**, flexible schedule with coordination windows * **Contractor** engagement (independent contractor/freelancer) * Time zone: **LATAM preferred** (overlap with US time helpful) * Direct collaboration with founders and leadership team. * Opportunity to build **cutting\-edge AI SaaS** used by enterprise clients. * Growth path: potential to evolve into **Lead Engineer** as the company scales. **Note:** As our hiring teams are global, please submit your resume in **English,** desired compensation (monthly) in ARS$/USD, cv and your **GitHub/portfolio**. Tipo de puesto: Tiempo completo, Por contrato Pregunta(s) de postulación: * What is your expected monthly contractor rate USD? (LATAM based) * Describe your experience with Python \+ FastAPI. * What is your level of English (written \& spoken)? (Beginner, Intermediate, Advanced — provide examples of usage in past roles.) * Have you implemented RAG pipelines with LLMs? (Please describe the stack you used — e.g., vector DB, embedding models, LangChain, etc.)