Backend Engineer — Buenos Aires, Argentina

Description

Summary: Seeking a Backend Engineer to extend an AI platform using Node.js/NestJS, building a proxy backend for inference runtime and expanding dashboards. Highlights: 1. Extend a proven SaaS foundation into a new AI runtime platform. 2. Build the proxy backend for a new AI platform. 3. Work with cutting-edge AI language models in a stealth-mode startup. ### **About Us** We are a **stealth\-mode startup** building a new AI platform. Our mission is to make advanced language models deployable, customizable, and secure across diverse environments. ### **Role** We are seeking a **Backend Engineer (Node.js/NestJS)** to extend our platform using our existing codebase. You’ll build the **proxy backend** that interacts with our custom inference runtime and extend dashboards. This role requires strong backend engineering skills, the ability to integrate existing systems, and comfort working closely with C\+\+/CUDA engineers building low\-level runtime features. ### **Responsibilities** #### **Proxy Backend for Inference Runtime** * Build and maintain a **Node.js\-based proxy backend** that: + Accepts inference requests from the frontend. + Schedules and serializes prompts. + Manages **QKV cache load/unload**. + Provides APIs to **manage LoRA adapters**. * Integrate with authentication, RBAC, and logging already provided by the existing stack. * Expose metrics and logs for monitoring inference usage and performance. #### **Dashboards** * Extend the existing Dashboard with Dataset upload, training job view, model management, inference usage, request history, and adapter selection. * Reuse **auth, billing, and user management code** (Auth0, Stripe). * Add necessary backend endpoints to support new UI flows. #### **Core Stack \& Infrastructure** * Develop using **NestJS** as the main backend framework. * Work with **PostgreSQL, Redis, and HashiCorp Vault** for persistence, caching, and secrets. * Use **Socket.IO** for real\-time updates (job status, inference progress). * Ensure secure integration with Stripe (billing) and Auth0 (identity). * Collaborate with DevOps on deployment pipelines (Proxmox, Docker, CI/CD). ### **Requirements** * Strong experience with **Node.js** and **NestJS** framework. * Proficiency in **PostgreSQL** and **Redis** for persistence and caching. * Hands\-on experience with **Socket.IO** or other WebSocket libraries. * Experience with **secure configuration and secrets management** (HashiCorp Vault preferred). * Comfortable working with **microservices** and integrating with existing codebases. * Strong debugging and systems thinking — able to reason about scheduling, state management, and concurrency. ### **Nice to Have** * Experience integrating with **AI runtimes** (gRPC/REST backends for inference). * Experience with RAG and MCP. * Experience with **authentication/authorization frameworks** (Auth0, JWT, RBAC). * Familiarity with **Stripe API** or similar billing systems. * Contributions to backend open\-source projects. * Experience with WebRTC. ### **Why Join** * Extend a proven SaaS foundation into a **new AI runtime platform**. * Competitive compensation, equity potential.