Fullstack Developer, AI Applications

About OpenTrain OpenTrain is the centralized, open platform where AI training and data-labeling freelancers find work, consolidate opportunities across platforms, and build a unified AI training portfolio they control. We make specialized AI training work easier to track, apply for, and grow into a durable freelance career. About this role OpenTrain is recruiting for a Fullstack Developer, AI Applications to build user-facing applications, APIs, and integrations on top of large language model infrastructure. You will turn model inference capabilities into reliable, scalable product features across frontend and backend systems, contributing to AI projects involving foundation models, evaluation, and reasoning. What you will do Build and ship end-to-end web applications spanning frontend interfaces, backend services, and APIs. Integrate LLM inference endpoints using REST, gRPC, streaming responses, server-sent events, and WebSockets. Develop scalable backend services with GCP products such as Cloud Run, Cloud Functions, Firestore, Cloud SQL, and GCS. Create asynchronous workflows using job queues, webhooks, and long-running inference tasks. Design and maintain integrations with relational and NoSQL databases and external services. Support deployment, monitoring, reliability, and application performance in collaboration with infrastructure and DevOps teams. Required skills Strong software development experience with Python and Node.js or TypeScript. Hands-on frontend development experience with React, Next.js, or a comparable modern framework. Strong API design knowledge, including REST APIs and one or more of streaming, server-sent events, WebSockets, or gRPC. Experience integrating LLM APIs or model inference endpoints into production applications. Experience with Docker, Git, CI/CD pipelines, relational databases, NoSQL databases, and GCP services is valuable. Why work with OpenTrain OpenTrain gives freelancers one place to manage AI training opportunities instead of rebuilding proof of work on every platform. A stronger OpenTrain profile helps you show credible experience, discover roles that match your skills, and turn AI training and data-labeling work into a long-term portfolio.