Senior Full Stack Engineer

About The CirqleThe Cirqle is building the autonomous operating system for creator marketing. Brands use our platform to run creator campaigns end to end: brief, sourcing, contracts, content approval, shipping and paid amplification on Meta and TikTok. More and more of that work is now done by agents. Brands can run campaigns through The Cirqle MCP from their own AI assistant. Inside the platform, an agent tells them what to do next and does it with them.We’re at a stage where architecture, scale and product quality all matter.The roleYou’ll work on the core platform and on the agents that run on top of it. Some projects are classic backend work, and others are about making agents reliable enough for brands to trust them with their campaigns.What you’ll doBuild and scale backend services and APIs in Node.js and TypeScriptBuild the tools and actions our agents use to run campaigns on behalf of brandsWork on agent context, memory and guardrails, and measure quality and cost with evals and tracingTurn manual operations into automated flows, such as creator outreachIntegrate with Meta, TikTok, Shopify and payment providersBuild background jobs and event-driven pipelinesOwn what you ship in production: reliability, observability and costOur tech stack (you don’t need to know everything)Backend: Node.js, TypeScript, Express, NestJSFrontend: Vue.js, NuxtAI: LLMs, MCP, tool calling, embeddings, vector search, evalsInfra: AWS (ECS, RDS, S3, SQS, Lambda, CloudFront)Databases: PostgreSQL, MongoDBCI/CD: GitHub ActionsObservability: CloudWatch, Sentry, PostHogWhat we’re looking for5+ years of experience as a software engineerStrong backend fundamentals (APIs, databases, async systems)Comfortable with TypeScript and modern JavaScriptYou have shipped LLM features to production and know where they break: context, tool calling, evaluation, latency and costExperience building production systems on cloud infrastructureProduct-minded: you care why something is built, not just howYou enjoy ownership and moving fast without breaking thingsYou write automated tests, and you treat agents the same way: a prompt or tool change ships with an evalNice to haveExperience building MCP servers or agent systemsExperience with AWS ECS or similar container platformsEvent-driven or queue-based architecturesExperience in marketplaces, SaaS or ad-techWhy The CirqleSmall, senior team with real ownershipYou build the agents and the platform they act on, not a chatbot bolted onto a dashboardArchitecture decisions actually matterNo agency vibes, no endless meetingsCompetitive salarywe are really nice.