Job description
We are a well-funded, stealth-mode project building a next-generation SaaS platform from the ground up. We are looking for a foundational, expert-level backend developer with strong full-stack sensibilities for a long-term engagement. This is more than a contract; we are seeking a true technical partner to help us architect and build the core of our system.
We have a complete, high-fidelity interactive prototype and a clear architectural vision. We value deep technical expertise and have designed a structured, professional hiring process to find the right fit.

The Project & Core Technical Challenge
We are building a sophisticated, multi-tenant SaaS application designed to function as an "Intelligence Layer" for our users. The core of this project is to ingest user-provided data about specific entities, enrich this data through both third-party APIs and a proprietary LLM-driven insight engine, and then orchestrate personalized, stateful action plans based on dynamic profiles.

The key technical challenges include:
Designing a flexible, scalable data enrichment pipeline that integrates with external APIs in real time.
Building a dynamic task/action generation engine powered by LLMs using the Vercel AI SDK.
Implementing a closed-loop feedback system that tracks action effectiveness and continuously improves AI output.

Your Responsibilities
Lead backend development from initial build to scalable production deployment.
Architect secure, high-performance APIs in TypeScript using Express (and/or Next.js API routes).
Design and maintain PostgreSQL schemas to handle complex user/entity/action relationships.
Integrate with LLM providers (e.g., OpenAI, Anthropic) via the Vercel AI SDK, and apply prompt engineering best practices.
Collaborate with the frontend team to ensure smooth integration with our TailwindCSS-powered Next.js UI.
Write robust unit and integration tests to ensure code quality and reliability.
Optimize application performance for scalability and low latency.

Required Tech Stack & Experience – “Must Haves”
Expert-level proficiency in TypeScript and Next.js.
Strong experience with Express.js and API architecture.
Solid experience designing schemas and writing queries in PostgreSQL.
Hands-on experience with LLM integration and the Vercel AI SDK.
Deep understanding of building secure, scalable multi-tenant SaaS backends.
Familiarity with TailwindCSS for rapid UI development and integration with backend logic.

Preferred Skills – “Nice to Haves”
Experience with streaming AI responses and building conversational interfaces.
Knowledge of cloud deployment best practices (Vercel, AWS, or similar).
Familiarity with Docker and CI/CD pipelines.
Experience with real-time APIs (WebSockets, SSE).
Prior work with third-party data enrichment APIs.