Senior Software Engineer – Backend (USA Only, 100% Remote)
WFA Digital Insight
Close's unique approach to blending AI into every aspect of their sales software sets them apart in the CRM space. This Senior Software Engineer role, focusing on the backend, is pivotal in driving this vision forward. With a tech stack that includes Python Flask and a range of data stores like MongoDB and PostgreSQL, the successful candidate will need to be adept at managing complex systems and contributing to a highly automated infrastructure. The opportunity to work on a product that aims to make sales easier and more efficient for businesses is a compelling one, especially within a company that values open-source contributions and continuous learning.
Job Description
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 https://stackshare.io/close-crm/close consists primarily of Python Flask web apps with our TaskTiger https://github.com/closeio/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 https://developer.close.com/ 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 https://github.com/closeio and on The Making of Close https://making.close.com/, our behind-the-scenes Product & Engineering blog. Check out our open source projects like SocketShark https://github.com/closeio/socketshark, TaskTiger https://github.com/closeio/tasktiger, LimitLion https://github.com/closeio/limitlion and ciso8601 https://github.com/closeio/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. OUR TEAMS When you apply, you’ll have an opportunity to highlight the team that appeals to you the most. We’ll do our best to honor this preference, but we'll also be evaluating skillset fit and the needs of the business. One thing to know up front: 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’ll start, but over time you’ll likely have the opportunity to work on many different projects. The work splits roughly like this. Pick the team that excites you most: - Agents. Build Close’s agentic platform and customer-facing AI experiences. Voice Agents, Custom Agents, and Ask Chloe are already in flight. You’d work on the shared intelligence and orchestration layer that powers AI-driven processes across the product. That includes the ecosystem around our APIs and MCP surface, which enables external agents like Claude and ChatGPT to operate Close. This team is pushing deeper into applied AI, retrieval, and agent infrastructure more than ever before.
- Communications. Own the voice, SMS, and email infrastructure powering Close — Twilio, WebRTC, WebSockets, AssemblyAI, ElevenLabs, and more. You’ll help build our voice, messaging, and conversational AI agents while scaling real-time AI across calls, email, and calendar sync infrastructure.
- CRM.
- Growth. Run the experiments and own the billing infrastructure that turn trials into paid customers. Stripe metered billing, AI credit top-ups, the activation and conversion funnel, and the team's biggest bet right now: agentic onboarding (an agent that walks new customers through setup, configuration, and first comms).
- 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.
- Working with AI in your day-to-day. You use AI tools in your own 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.
- A builder first.
- Opinionated about API design for modern software. You've shipped internet-facing APIs and you think about who's on the other end - apps, agents, humans poking around in docs - and what each of them needs.
- Battle-tested.
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. You'll 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): We 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 https://www.close.com/blueprint.
How to Stand Out
- Ensure your portfolio includes examples of complex backend projects you've managed, especially those involving Python Flask and distributed systems.
- Prepare to discuss your experience with cloud platforms, particularly AWS, and your understanding of security measures for data integrity.
- Familiarize yourself with Close's tech stack and be ready to discuss how your skills align with their current and future needs.
- Highlight any experience you have with AI integration, even if it's not directly related to sales software, to demonstrate your versatility.
- Be prepared to talk about your approach to problem-solving and how you handle complex technical issues in a collaborative environment.
- Show enthusiasm for open-source contributions and a willingness to learn and adapt to new technologies and methodologies.
- When discussing your career goals, emphasize how this role aligns with your aspirations and what you hope to achieve in the position.
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