Software Development Engineer III || LC Phone

About HighLevel   HighLevel is an AI-powered business operating system that gives agencies, entrepreneurs and SMBs the infrastructure to build, automate and scale. Today, HighLevel supports SMBs across 150+ countries, fueling community-driven growth rooted in real customer outcomes. To date, businesses operating on HighLevel have generated over $7 billion in ecosystem value, demonstrating the impact of shared infrastructure at scale. By centralizing conversations, automation and intelligence into one system, we help businesses move faster, reduce complexity and execute efficiently. Behind the platform, HighLevel powers more than 4 billion API hits and 2.5 billion message events daily. With 250 terabytes of distributed data, 250+ microservices and over 1 million domain names supported, our architecture is built for performance, resilience and long-term scalability. Our people With over 2,000 team members across 10+ countries, HighLevel operates as a global, remote-first organization built for speed and ownership. We value initiative, clarity and execution, creating space for ambitious people to build systems that support millions of businesses worldwide. Here, innovation thrives, ideas are celebrated and people come first, no matter where they call home. Our impact Every month, HighLevel enables more than 1.5 billion messages, 200 million leads and 20 million conversations for the more than 1 million businesses we support. Behind those numbers are real people building independence, expanding opportunity and creating measurable impact. We’re proud to be a part of that. Learn more about us on our YouTube Channel or Blog Posts   About the Role   We’re looking for a Software Development Engineer III with deep expertise in Node.js, MongoDB, and distributed systems, along with a strong focus on platform stability, scalability, and long-term technical excellence. You’ll join the platform team within our LC Phone System, which provides capability for purchasing phone numbers, Messaging, Calling, Compliance and Platform.  This role is backend-heavy, involving platform-level challenges such as system stability, performance optimization, tech debt reduction, security hardening, and cost efficiency. You’ll work on foundational improvements that enable the entire Phone System (including Calling, Messaging, and related services) to operate seamlessly under increasing demand. Responsibilities

Stabilize & Scale the Platform: Tackle systemic bottlenecks, improve fault tolerance, and ensure high availability for mission-critical phone services.

Efficiency & Performance: Optimize resource usage (CPU, memory, network) to handle millions of operations while reducing cloud costs.

Tech Debt & Modernization: Lead long-term refactoring efforts, deprecate legacy systems, and introduce scalable patterns.

Security & Compliance: Strengthen data protection, access controls, and auditability across the platform.

Developer Velocity: Improve tooling, observability, and automation to accelerate engineering workflows.

Cross-Team Collaboration: Work with product, infrastructure, and other engineering teams to align on platform priorities.

Mentorship & Leadership: Guide engineers, set architectural standards, and drive the platform roadmap.

Requirements

4+ years of backend engineering experience, including designing fault-tolerant systems and working on high-scale platforms.

Deep expertise in distributed systems, event-driven architectures, and asynchronous job processing

Strong experience with relational and NoSQL data models (especially with complex temporal data)

Proven track record of architecting complex systems and delivering scalable, high-performance web apps in production.

Strong understanding of software design patterns, API design, and microservices architecture in a multi-tenant environment.

Skilled in guiding technical architecture, making high-impact engineering decisions, and mentoring fellow engineers.

Experience with code quality practices, automated testing, CI/CD pipelines, and dev tooling optimization.

Excellent problem-solving skills, with clear and collaborative communication across 

Preferred Experience

Experience with AI Tools and contributions to open-source tools, internal platforms or engineering blogs

Experience with modern front-end frameworks (e.g., React, Vue, Angular) and building full-stack web applications.