Staff Full Stack Engineer, Contacts

Calendly is a rapidly growing company that helps millions of users manage their scheduling needs. They are seeking a Staff Engineer to lead critical parts of their Contacts stack, focusing on system reliability and evolving their architecture to support new workflows.

Responsibilities:

• Own critical parts of our Contacts stack end-to-end, from technical design to rollout and ongoing reliability
• Guide the evolution from early-stage architecture to a scalable, well-instrumented, multi-tenant system that other teams can safely build on
• Lead big, cross-cutting “0–1 to 1–100” initiatives in partnership with Product, Design, and other Engineering teams
• Raise the technical bar for the team through mentoring, eng leadership, and high-quality execution
• Design and evolve services and data models for contacts and relationships that can support new workflows and downstream consumers
• Drive decisions around our APIs, eventing, and data flows to keep Contacts a reliable system of record
• Own complex, high-impact projects (e.g., new ingestion pipelines, enrichment features, or contact-centric workflows) from technical discovery through launch and iterative improvement
• Break down ambiguous problem spaces into clear milestones and incremental, ship-as-you-go plans
• Provide technical leadership across squads and workstreams, helping teams make good tradeoffs on performance, reliability, and complexity
• Mentor senior and mid-level engineers, review design docs and PRs, and codify best practices in testing, observability, and production readiness
• Collaborate with PMs and designers to translate customer problems into pragmatic solutions, especially for solopreneurs and small teams adopting CRM for the first time
• Help define MVP scopes, instrumentation, and learning loops so we can move fast without compromising trust or data quality
• Define and improve SLOs, error budgets, and operational playbooks for Contacts services
• Participate in on-call, guide incident response, and drive durable corrective actions that reduce repeat issues

Requirements:

• Deep experience (typically 8–10+ years) building and operating backend or full-stack systems in B2B SaaS, with meaningful time at Staff level or higher
• Proven track record leading 0–1 products and scaling them through maturity including making and revisiting foundational architectural decisions
• Strong background in distributed systems, data modeling, and API design; experience with high-traffic, high-availability platforms is a plus
• Fluency in at least one of our primary stacks (e.g., Go, TypeScript/Node, React) and comfort moving across the stack where needed
• Experience with modern cloud infrastructure (GCP or similar), container orchestration (Kubernetes), and relational databases like PostgreSQL; familiarity with eventing, CDC, or search platforms is a plus
• Strong testing discipline (unit, integration, and end-to-end), observability (logging, metrics, tracing), and performance tuning
• Experience with CRMs, marketing/sales tooling, or other data-centric systems where data quality and trust matter
• Comfort working in product-led environments, where you balance speed, quality, and learning (what to build now vs. later, and how to de-risk via MVPs and experiments)
• Demonstrated ability to incorporate customer signals and data into technical decisions
• History of acting as an org-level technical leader - shaping strategy, influencing roadmaps, and aligning multiple teams around a coherent technical direction
• Excellent written and verbal communication; comfortable bringing strong, opinionated recommendations into group settings while staying collaborative and low-ego
• Experience mentoring and leveling up other engineers; you see your success through the impact of the teams around you
• Availability to participate in an on-call rotation for business-critical services
• Authorized to work lawfully in the United States (Calendly does not provide immigration sponsorship at this time)