Full-Stack Software Engineer

Concentrate AI is hiring a remote Full-Stack Software Engineer to build customer-facing products and internal tools across its API platform for accessing and managing AI models. The role involves taking features from database design through deployment, working mainly in TypeScript with Node.js, React, and preferably Next.js, plus backend frameworks such as Fastify, PostgreSQL, Docker, and CI/CD. The company wants someone with at least two years of experience who is comfortable with authentication, testing, and scalable system design. This role should suit a self-directed engineer who likes working closely with founders in a fast-moving startup environment.

FULL-STACK SOFTWARE ENGINEER Concentrate provides one OpenAI-compatible API to access, route, and manage models across leading AI providers and open-source models through a single endpoint. We help teams save time, lower token spend, improve reliability, and avoid vendor lock-in. Supported by top-tier VCs. This is a remote role with preference for SF based candidates. THE ROLE We’re looking for a Full-Stack Software Engineer who can own features end-to-end, from database schema design through production deployment. You’ll work across our entire stack to build customer-facing products and internal tools, with significant autonomy and direct impact on the business. WHAT YOU’LL DO - Design and implement full-stack features using modern TypeScript across the frontend and backend - Architect, build, and maintain robust RESTful APIs with proper authentication, validation, and error handling - Maintain high engineering standards through comprehensive testing, including unit, integration, and end-to-end tests - Containerize and deploy services using Docker and CI/CD pipelines - Collaborate closely with the founding team on product direction, architecture, and technical strategy - Contribute to scalable, maintainable system architecture in a fast-moving startup environment REQUIREMENTS - 2+ years of experience - Strong proficiency with TypeScript and Node.js - Experience building production-grade frontends with React; Next.js preferred - Familiarity with modern frontend tooling, such as Tailwind and component libraries - Backend development experience with frameworks like Fastify or similar - Solid understanding of PostgreSQL, including schema design and query performance - Familiarity with Docker, CI/CD workflows, and cloud deployment environments - Experience implementing secure authentication flows, such as JWT or OAuth - Strong testing discipline — you write tests as part of building features, not after the fact NICE TO HAVE - Experience with type-safe ORMs such as Kysely, Drizzle, or similar - Knowledge of Redis for caching and performance optimization - Comfort with Nginx configuration, reverse proxies, and SSL/TLS setup - Experience with monorepo tooling such as Turborepo or Nx - Prior work on SaaS platforms or multi-tenant architectures OUR PROCESS Candidates complete a take-home technical assessment aligned with our real engineering work: building a small but complete application involving multiple user roles, API design, authentication, testing, and deployment. We evaluate code quality, architectural decisions, and your approach to trade-offs — not trick questions. COMPENSATION We offer a competitive salary, early-stage equity, and the opportunity to influence both our product and culture. If you thrive on ownership and want to help shape a company from its earliest days, you’ll fit right in. FAQs What is Concentrate AI? Concentrate AI is an OpenAI-compatible API and fully managed multi-provider LLM platform that lets teams access, route, and manage models from leading AI providers and open-source models through one secure endpoint. How is Concentrate different from OpenRouter? Concentrate is similar to OpenRouter, but built for enterprise teams that need stronger security, rich usage analytics, centralized billing, production reliability, model fallbacks through a fully managed platform. How is Concentrate different from LiteLLM? LiteLLM is a flexible developer tool for routing LLM calls, while Concentrate is a secure, fully managed, enterprise-ready platform with provider routing, model fallbacks, observability, usage analytics, centralized billing, and one bill for all token usage. Equal Opportunity & Fair Chance Notice Concentrate AI is an affirmative action and equal opportunity employer. We are committed to providing equal employment opportunities and do not discriminate in recruiting, hiring, training, promotion, or other employment practices on the basis of race, color, sex, age, religion, national origin, ancestry, protected veteran status, disability, sexual orientation, gender identity or expression, genetic information, or any other status protected by applicable law. Qualified applicants with arrest and conviction records will be considered in accordance with the San Francisco Fair Chance Ordinance and applicable state and local laws. California Privacy Notice California residents may contact privacy@concentrate.ai for additional information regarding how we collect, use, and disclose personal information during the job application process. Recruitment Agency Notice Concentrate AI does not accept unsolicited resumes from recruitment agencies and is not responsible for any fees related to unsolicited submissions.