Senior Software Engineer - Backend Platforms (USA Only, 100% Remote)

Close is a remote company building an AI-powered CRM and sales software to help teams sell more efficiently. The Senior Software Engineer will help establish the Backend Platform team by building shared backend infrastructure, API patterns, observability systems, development environments, and AI-powered engineering tools for internal developers.

Responsibilities:

• Expand DevDawg and Spice. Cloud development environments for our full stack, paired with automated review and root-cause tooling that can approve real pull requests. Making that safe enough to cover more of our review surface is one of the team's biggest single bets
• Build the paved roads for our API layer. REST blueprints, GraphQL schema, OpenAPI, realtime, and the auth and permission plumbing that every endpoint needs. Consistent patterns are what make shared utilities possible in the first place
• Modernize the backend framework layer. Web and async compute frameworks, performance, and migration paths (Flask → FastAPI, among others) — with clear defaults, examples, and migrations teams can adopt without asking permission
• Own how we see production. Observability, metrics, alerting, and the readiness bar teams meet before shipping. When the same issues keep showing up in incident reviews, you make sure the underlying cause gets owned rather than re-triaged
• Ship shared backend services and primitives. Eventing patterns and the event log, database-change safety and migration guardrails, delegated access and auditability, the internal admin framework and support-facing APIs
• Set the guardrails for coding agents in our backend. Static analysis, linting, hooks, test harnesses — the constraints that make agent-written code safe to merge at volume
• Partner across the org. Infrastructure owns the substrate (AWS, Kubernetes, datastores); you own the application layer on top

Requirements:

• A seasoned Python engineer
• Go, Rust, or TypeScript alongside it is welcome
• You've shipped meaningful LLM-backed or agentic work to real users
• You use coding agents in your own workflow and have a real POV on where they help and where they get in the way
• Fluent in observability and production practice
• You've been the person who made a system legible when it broke
• You've shipped internet-facing APIs and you think about who's on the other end — apps, agents, humans reading docs — and what each needs
• You've debugged incidents where latency budgets didn't hold, owned a system everyone else relied on, or carried a pager for something with real customer impact
• Drawn to meta-problems
• AI-native in production
• Working with AI in your day-to-day
• Opinionated about API design
• Battle-tested
• A builder first
• Energized by internal customers