Senior Full-Stack AI Developer / Technical Lead for Intelligent Personal Assistant MVP

Senior Full-Stack AI Developer / Technical Lead for Intelligent Personal Assistant MVP ABOUT THE PROJECT Harriet AI is an early-stage intelligent personal assistant designed to help people organise their work, manage their knowledge, and make better decisions. We have already completed substantial product planning, system architecture, and an implementation roadmap. We are now moving into practical MVP development and are looking for a senior, hands-on developer or technical lead who can help turn this foundation into a secure working product. This is not simply a chatbot project. The product will eventually combine conversational AI, private knowledge/document intelligence, task management, user-controlled memory, and meeting intelligence within a secure personal workspace. INITIAL TECHNICAL DIRECTION The current Version 1 direction includes: • Responsive web application • Next.js + TypeScript frontend • Python + FastAPI backend • PostgreSQL database • Vector retrieval / RAG capability • Managed authentication • Private object storage • Server-side AI/LLM orchestration • Background processing for document and meeting workflows • Managed cloud deployment We are open to well-reasoned technical recommendations. The selected developer should be able to review the existing architecture and explain any proposed changes before implementation. FIRST MILESTONE We do NOT want to attempt the entire Harriet AI platform immediately. The first working milestone will be: Sign in → Open Harriet → Send a message → Receive an AI response → Conversation is saved securely. The first engagement should therefore focus on: 1. Reviewing the existing product and architecture documentation. 2. Confirming or challenging the proposed technology stack. 3. Preparing the development/staging foundation. 4. Implementing secure authentication and user-data boundaries. 5. Building the first Harriet conversational vertical slice. 6. Persisting conversations securely. 7. Adding basic automated tests and monitoring. 8. Demonstrating the working milestone in a controlled non-production environment. WHAT WE ARE LOOKING FOR You should have strong practical experience with: • Production full-stack web application development • TypeScript / React / Next.js • Python backend/API development, ideally FastAPI • PostgreSQL and database migrations • Authentication and server-side authorisation • Secure multi-user SaaS architecture • Cloud deployment and CI/CD • Secrets and environment management • LLM/API integration • Embeddings, vector search and RAG • Automated testing and production observability Experience with document ingestion, knowledge systems, speech-to-text, meeting intelligence, OAuth integrations, or privacy-sensitive productivity software would be particularly valuable. SECURITY MATTERS Harriet AI will handle private user information. Security and privacy therefore cannot be treated as features to add later. The selected developer must understand object-level authorisation, cross-user data isolation, private file storage, secure secret management, and safe AI/RAG architecture. A user must never be able to access another user's conversations, documents, knowledge, or other private data. HOW WE WANT TO WORK We are looking for someone who: • Can explain technical decisions clearly to a non-technical founder. • Can work from existing product and architecture documentation. • Can challenge decisions constructively when there is a better technical approach. • Prefers simple, maintainable MVP architecture over unnecessary complexity. • Documents important decisions. • Uses Git and pull requests professionally. • Demonstrates progress through small, testable milestones. • Takes security, privacy, testing, and code quality seriously. This may become a longer-term engagement if the initial collaboration is successful, but the first contract will be deliberately controlled and milestone-focused. WHEN APPLYING Please include: 1. A short introduction. 2. Examples of relevant production products you personally helped build. 3. Your exact role/contribution to those projects. 4. Your experience with Next.js/React, Python/FastAPI, PostgreSQL, and cloud deployment. 5. Your practical experience with LLM APIs, embeddings, vector databases, and RAG. 6. An example of how you have handled authentication/authorisation in a multi-user application. 7. A brief explanation of how you would approach our first milestone: Sign in → AI chat → response → securely saved conversation. 8. What you would deliberately NOT build during that first milestone. 9. Your availability and time zone. 10. Your hourly rate. Please do not send a generic AI-generated proposal that does not address the questions above. We are more interested in demonstrated engineering judgement, security awareness, communication, and relevant implementation experience than in the number of technologies listed on your profile.