Senior Full Stack Engineer

About The Cirqle

The 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 role

Y ou’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 do

• Build and scale backend services and APIs in Node.js and TypeScript
• Build the tools and actions our agents use to run campaigns on behalf of brands
• Work on agent context, memory and guardrails, and measure quality and cost with evals and tracing
• Turn manual operations into automated flows, such as creator outreach
• Integrate with Meta, TikTok, Shopify and payment providers
• Build background jobs and event-driven pipelines
• Own what you ship in production: reliability, observability and cost

Our tech stack (you don’t need to know everything)

• Backend: Node.js, TypeScript, Express, NestJS
• Frontend: Vue.js, Nuxt
• AI: LLMs, MCP, tool calling, embeddings, vector search, evals
• Infra: AWS (ECS, RDS, S3, SQS, Lambda, CloudFront)
• Databases: PostgreSQL, MongoDB
• CI/CD: GitHub Actions
• Observability: CloudWatch, Sentry, PostHog

What we’re looking for

• 5+ years of experience as a software engineer
• Strong backend fundamentals (APIs, databases, async systems)
• Comfortable with TypeScript and modern JavaScript
• You have shipped LLM features to production and know where they break: context, tool calling, evaluation, latency and cost
• Experience building production systems on cloud infrastructure
• Product-minded: you care why something is built, not just how
• You enjoy ownership and moving fast without breaking things
• You write automated tests, and you treat agents the same way: a prompt or tool change ships with an eval

Nice to have

• Experience building MCP servers or agent systems
• Experience with AWS ECS or similar container platforms
• Event-driven or queue-based architectures
• Experience in marketplaces, SaaS or ad-tech

Why The Cirqle

• Small, senior team with real ownership
• You build the agents and the platform they act on, not a chatbot bolted onto a dashboard
• Architecture decisions actually matter
• No agency vibes, no endless meetings
• Competitive salary
• we are really nice.