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

About the role

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.

• CI/CD pipelines that build Docker images, run automated tests and deploy to Kubernetes clusters
• Docker images used in local development environment allowing coding locally against all services
• Well-documented public API consumed by our front-end JavaScript app and numerous integrations
• Infrastructure heavily automated using Terraform, Ansible and other AWS tools
• Active open-source contributions on GitHub and The Making of Close, our behind-the-scenes Product & Engineering blog
• Open source projects include SocketShark, TaskTiger, LimitLion and ciso8601

AI is both how we build and what we ship, reshaping what engineering looks like. This transformation is something we’re embracing and find deeply exciting.

Our Teams

When you apply, you’ll have an opportunity to highlight the team that appeals to you most. We’ll do our best to honor this preference, but we'll also evaluate skillset fit and business needs. One key aspect: we move people between teams as work shifts. Most engineers here end up on more than one team over time—this is where you’ll start, but you’ll likely have opportunities to work on many different projects.

• Agents: Build Close’s agentic platform and customer-facing AI experiences. Voice Agents, Custom Agents, and Ask Chloe are already in flight. Work on the shared intelligence and orchestration layer powering AI-driven processes across the product, including the ecosystem around our APIs and MCP surface, enabling external agents like Claude and ChatGPT to operate Close. This team is pushing deeper into applied AI, retrieval, and agent infrastructure.
• Communications: Own the voice, SMS, and email infrastructure powering Close—Twilio, WebRTC, WebSockets, AssemblyAI, ElevenLabs, and more. Help build our voice, messaging, and conversational AI agents while scaling real-time AI across calls, email, and calendar sync infrastructure.
• CRM: Build the structured context layer that humans and agents both depend on. Rebuild the data model to flex with real businesses, make the CRM agent-ready (retrieval, traversal, action coverage through MCP and our public API), and ship next-generation AI-native CRM features (AI Enrich, Autofill, AI Search). Operate on billions of Mongo documents with Elasticsearch underneath.
• Growth: Run experiments and own the billing infrastructure that turns trials into paid customers. Work with Stripe metered billing, AI credit top-ups, the activation and conversion funnel, and the team’s biggest bet: agentic onboarding (an agent that walks new customers through setup, configuration, and first comms). Hypothesis-driven and metric-first.

Requirements

• Seasoned engineer: Python is our backbone, but you may have worked across Go, Rust, or TypeScript. You pick the right tool for the problem rather than retreating to what you know. You’ve seen a variety of problems, can collaborate, and self-direct.
• Building AI: You've shipped LLM-backed features for real users and have a POV on where they're trustworthy, where they fall over, and how to get them production-ready when customers bet revenue on the output. Experience with Pydantic, Temporal, LangFuse, and other modern AI infrastructure tooling to power our agent platform.
• Working with AI daily: You use AI tools in your workflow to ship faster, write tighter code, and reason about unfamiliar parts of the codebase. We fund the use of AI tools (Claude Code, Codex, and other best-in-class developer tools) and treat learning and experimentation as part of the work.
• Builder first: You’d rather get the first iteration of a feature in front of fifty customers than spend three weeks fretting over a perfect PR. You ship.
• Opinionated about API design: You've shipped internet-facing APIs and think about who's on the other end—apps, agents, humans poking around in docs—and what each needs.
• Battle-tested: 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.

Benefits

• Compensation: Competitive pay plus an organization-wide goal-based bonus
• Paid Time Off: ~5 weeks of PTO to start, plus a 1-week all-company Winter Holiday Break and paid US holidays. Earn 2 extra days for every year you're with Close.
• 80% Work Option: Work with your manager to choose between a standard 5-day week or a 4-day week at 80% pay
• Parental Leave: Paid leave for primary and secondary caregivers
• Sabbatical: A 1-month paid sabbatical every 5 years with the team
• Healthcare (US residents): Two medical plans with Close covering 99% of your premium, plus Dental, Vision, HSA, FSA, and company-paid Long-Term Disability
• 401k (US residents): Match your contributions up to 6%, vested immediately

Our Values

• Build a house you want to live in: Examine long-term thinking and action
• No BS: Practice transparency and honesty, especially when it’s hard
• Invest in each other: Build successful relationships with your coworkers and customers
• Discipline equals freedom: Keep your word to yourself and others
• Strive for greatness: Constantly challenge yourself and others

Learn More

• Listen to our CEO and Founder, Steli Efti, tell the story of Close’s journey in the $0-30m Blueprint.
• Watch our culture video from our 2023 team retreat in Milan.
• Every year our entire team gathers in person to build connection, foster cross-functional collaboration, and have fun. In 2027, we're headed to Dusseldorf, Germany!
• Explore our product. Check out a demo!