Senior Full-Stack Developer – Private AI Operations Platform

I’m looking for a senior full-stack developer to help me build a private, action-capable AI platform that integrates with business systems such as BigChange, Outlook (Microsoft Graph), Google Drive, and later Xero, using OpenAI as a reasoning engine.

This is not a chatbot or prompt-engineering project. It’s a secure internal SaaS-style system with real write access to APIs.

What the platform will do

Chat-style interface (similar to ChatGPT)

Secure user login and role-based permissions

Interpret user intent via OpenAI

Execute validated actions via APIs (e.g. create purchase orders in BigChange)

Read/write data to external systems (BigChange required, Xero later)

Store knowledge and precedent in a vector database

Allow file uploads and document ingestion

Full audit logging and approval workflows

Designed to be extended and improved over time

Required experience (non-negotiable)

Senior full-stack development experience (5+ years)

Strong API integration experience (REST, OAuth, webhooks)

Experience with OpenAI / LLM APIs in production systems

Clear understanding of secure backend architecture

Experience building SaaS platforms or internal tools

Comfortable designing systems where AI plans but backend executes

Preferred tech stack (flexible but indicative)

Frontend: React / Next.js

Backend: Python (FastAPI) or Node.js (NestJS)

Databases: PostgreSQL, Redis

Vector DB: Pinecone / Qdrant / Weaviate

Auth: OAuth / JWT

Cloud: AWS / GCP / Azure

Very important

OpenAI must not hold API keys or perform actions directly

All actions must be validated and executed by the backend

Accuracy, safety, and auditability matter more than speed

Nice to have

Microsoft Graph API experience

Accounting or FM system integrations

Experience building approval workflows

Product-minded approach (not just coding to spec)

Engagement

Initial build: 6–8 weeks

Ongoing improvement work expected

Looking for someone I can work with long-term

Please do not apply if you only build chatbots, landing pages, or no-code automations.