Sr. Staff Engineer - Payments & Commerce Platform

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 building a global commerce platform to power $1T+ in annual transactions for millions of SMEs. We want our Principal Enggs to be the technical force‑multiplier who sets the domain modelling, architecture, raises the reliability bar, and multiplies team effectiveness. You’ll steward our core commerce models—subscriptions, payments , Catalog, Pricing, Inventory, fulfillment, reconciliation , tax —and the services around them, ensuring correctness by design, auditability, and delightful performance at scale. This is an IC role with org‑level influence (no direct reports), focused on designing systems, shaping standards, and growing engineers. Tech Stack: Backend: Go, ConnectRPC Databases: MongoDB, Firestore, ClickHouse Cloud: GCP (GKE), Pub/Sub, Redis, OpenTelemetry

What You’ll Do:: Architect and ship multi‑tenant, planet‑scale services (checkout, subscriptions, payments orchestration, invoicing, tax hooks) with clear domain boundaries (DDD) and hard SLOs Be the custodian of API & schema design: own protobuf/ConnectRPC conventions, versioning policy, deprecation playbooks, and Buf breaking‑change checks—so our contracts stand the test of time Guarantee resilience & availability of core payment paths: timeouts, retries with jitter, circuit breakers, idempotency keys, outbox/Saga patterns, hedged requests, and graceful degradation Ensure complete auditability: append‑only double‑entry ledger, immutable event streams, trace‑linked entities (OTel trace/span IDs), tamper‑evident trails, and reconciliations that tie out to the cent Own error boundaries end‑to‑end: enumerate failure domains (PSP, network, data, concurrency, quota, browser, device); design uniform error contracts; implement compensations/backfills and automated replay Keep track of every deployed thing: services, workers, triggers, cron, subscriptions—own the service catalog and scorecards (owners, SLOs, runbooks, PDBs, HPA/VPA, budgets, quotas, timeouts) Configuration & limits stewardship: enforce sane defaults across GKE, Pub/Sub, Redis, Firestore/Mongo, ClickHouse—connection pools, ack deadlines, batch sizes, TTLs, memory/FD limits, and GCP quotas Observability as a product: pervasive OpenTelemetry, RED/USE metrics, exemplars, trace sampling, SLO dashboards, and alerting that wakes humans only for user‑impacting issues Pr