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

About Us Since 2013, we’ve been building a CRM that gets out of your way and helps your team sell more, faster. Now we’re building AI into every part of it, so Close does the busywork and your team does the selling. No manual data entry, no 10-click workflows. Just communication-first, AI-powered sales software designed to help you succeed and scale. We're bootstrapped and profitable which means we answer to our customers and play by our rules. We're proud of our 120-person, 100% remote team, focused on building Close so that no small, scaling business fails because it can't figure out sales. Our Stack Our backend tech stack consists primarily of Python Flask web apps with our TaskTiger scheduler handling many of the backend asynchronous task processing chores. Our data stores include MongoDB, PostgreSQL, Elasticsearch, and Redis. The underlying infrastructure runs on AWS using a combination of managed services like EKS, MSK, RDS and ElastiCache and non-managed services running on EC2 instances. We have CI/CD pipelines that build Docker images, run automated tests and deploy to Kubernetes clusters. We also use these images in our local development environment allowing coding locally against all of our services. We have a well-documented public API that is consumed by our front-end JavaScript app as well as numerous integrations. Our infrastructure is heavily automated using Terraform, Ansible and other AWS tools. We love open sourcing our code and ideas on our GitHub and on The Making of Close , our behind-the-scenes Product & Engineering blog. Check out our open source projects like SocketShark , TaskTiger , LimitLion and ciso8601 . AI is both how we build and what we ship, and that's reshaped what engineering looks like. This is a transformation we’re embracing and find deeply exciting. About the Role The CRM team owns everything that Close’s customers touch all day, every day: leads, contacts, opportunities, tasks, activities, custom objects, and search. Each time a call is logged, an email is threaded, a meeting is summarized, it lands on the record this team owns, and every agent we ship starts there. Today, this team is making big moves towards the next iteration of Close's core data model, our largest engineering effort currently underway. We're reopening assumptions made a decade ago and asking what a modern CRM's data model should look like — one that makes Close flexible for our small, scaling business customers. This is a long series of migrations and rearchitecture projects. If you like greenfield and you like hairy, this is both: help design the next version of Close, and untangle the current one. One thing to know: we do move people between teams as the work shifts. Most engineers here end up on more than one team over their time at Close — this team is where you'd start, but over time you'll likely have the opportunity to work on many different projects. You are A seasoned engineer. Python is our backbone, but perhaps you've worked across Go, Rust, or TypeScript. You pick the right tool for the workload rather than retreating to what you know. Architecturally minded. This is the thing we care about most. You've designed systems others built on, planned a migration that couldn't take the product down, and know how to sequence a rearchitecture into pieces that ship independently. Drawn to data model and retrieval problems. Schemas, relationships, normalization, query design, type systems. The plumbing decides whether a CRM feels fast and we pride ourselves on being fast. Experienced in search — this is a serious bonus. Elasticsearch especially, and anything adjacent: Lucene internals, query planning, relevance, indexing at scale, building or operating a search engine. AI-native in production. You've shipped meaningful LLM-backed or agentic features to real users, and you have a POV on where AI earns its place in a CRM workflow and where a structured system wins. Wo