Senior SDE - Conversations

in the same window — with API traffic peaking at 28,000+ requests per second. Booking appointments, closing deals, answering customers. If these systems lag, businesses lose leads. If they go down, people lose income.

We're hiring backend engineers who treat that as a design constraint, not a fun fact.

This isn't a role where you'll implement someone else's spec. You'll be handed problems that don't have a known answer yet — a datastore buckling under index growth, a queue that needs to absorb 10x burst traffic without dropping a message, a state machine with millions of concurrent executions.

You'll figure it out. And you'll own it.

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.

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.

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

The systems that run millions of businesses.

Every month, 2.6 billion messages flow through our platform. Our automation engine enrolls 3.1 billion contacts and executes

21.5 billion workflow actions

Responsibilities

• The Conversations organization powers multi-channel communication across SMS, Email, WhatsApp, and DMs — handling over 2B messages each month. The Threads & Composer team owns the inbox and composer surfaces, and the backend services that deliver and store those interactions.You’ll work across Node.js microservices, GCP-based infra (GKE, Pub/Sub, Cloud Tasks), and MongoDB/Firestore storage layers, ensuring every message and UI state stays consistent, fast, and recoverable.

Node.js / Go services

• on critical paths — high throughput, low latency, zero tolerance for data loss
• architecture, design docs, code, tests, rollout, and production health
• Model and optimize data layers across
• SQL and NoSQL stores
• handling high read/write volumes and atomic updates

queueing, caching, and rate-limiting

• layers that keep the platform graceful under burst traffic
• Instrument everything — logs, metrics, traces — so you know your system is healthy before anyone asks
• Debug production incidents, ship the fix, drive the post-mortem to closure
• Review code, raise the bar, and pull the engineers around you up with you.

Requirements

• 4+ years
• of backend engineering experience, with deep hands-on work in
• Node.js and/or Go
• Queueing experience
• you've designed with Pub/Sub, Kafka, RabbitMQ, Cloud Tasks, or similar, and you understand delivery semantics, ordering, and backpressure
• Complex distributed systems experience
• consistency trade-offs, idempotency, fault tolerance, systems that stay correct under partial failure
• Hands-on with
• Redis or other in-memory data stores
• caching strategies, data structures, and their failure modes
• SQL or NoSQL databases
• schema design, indexing, and query optimization at high volume

You write

• clear design docs and rigorous test cases as a habit, not on request
• you make agents produce accurate, production-quality code, fast
• Languages: Node.js (TypeScript), Go
• Storage: MongoDB, Firestore, Redis, ElasticSearch, ClickHouse

Infra: GCP — GKE, Pub/Sub, Cloud Tasks

• fast. You know when to hand a problem to an agent and when to take the wheel. You review AI output with the same rigor as a junior engineer's PR, and you ship at a pace that engineers without this skill can't match.
• If you're still copy-pasting from a chat window and hoping, this isn't the seat for you.
• You've solved problems
• nobody handed you a playbook for
• ideally in a 0→1 environment where the system didn't exist until you built it
• You understand systems
• in depth
• not just the API surface, but what happens under load, at the tail, when the network partitions
• You write
• design docs people actually read
• clear trade-offs, honest risks, a real recommendation

You treat

• test cases as part of the design, not a chore after the fact
• When production breaks at 2 AM, your first instinct is curiosity, not panic

Preferred

• Familiarity with our stack: GCP, MongoDB, Firestore, ClickHouse, ElasticSearch
• You've built or scaled messaging, automation, or event-driven platforms
• You've taken a system from 0→1, or rebuilt one mid-flight without breaking it

Champion of AI-assisted engineering

On AI

• We're past the debate. AI is part of how we build — and we expect you to be better at it than most
• That means making agents do real work: producing code that's accurate, tested, and slop-free

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