Senior Software Engineer

Five9 is a leading provider of cloud contact center software, bringing the power of cloud innovation to customers worldwide. The Senior Software Engineer will modernize internal platform tooling and drive full-stack engineering maturity, focusing on 12-factor application compliance and architectural direction for IaaS platforms.

Responsibilities:

• Rapidly audit and refactor existing internal tools and services to strictly comply with 12-factor application principles — configuration via environment, stateless processes, explicit dependency declarations, disposability, and dev/prod parity
• Own end-to-end delivery of modernized services: back-end APIs (Go/Python) paired with clean, functional front-end interfaces (React or Vue) that surface platform data and controls to internal users
• Decompose monolithic or ad-hoc scripts into properly structured, independently deployable services with clearly defined interfaces
• Build and maintain internal web UIs using modern front-end frameworks (React or Vue) — dashboards, tooling consoles, and operational interfaces that teams actually want to use
• Design and develop robust REST/gRPC back-end APIs in Go and Python following clean architecture patterns
• Ensure front-end and back-end components are instrumented end-to-end with traces, metrics, and structured logs from day one
• Own the platform observability stack: design, implement, and continuously improve our Grafana, Prometheus, and Loki deployment for all internal services
• Define and enforce instrumentation standards — every new or refactored service must ship with meaningful RED metrics, structured JSON logs forwarded to Loki, and distributed traces
• Build and maintain Grafana dashboards and alerting rules that provide actionable signal for on-call engineers; define and manage SLIs/SLOs across critical platform services
• Implement Prometheus exporters for custom internal services and integrate alerting with PagerDuty or equivalent
• Drive log aggregation strategy with Loki — label taxonomy, retention policies, and LogQL query libraries for common operational queries
• Design, develop, and support robust APIs and automation services from scratch using Go and Python
• Conduct architecture reviews and enforce design standards across the platform engineering team
• Drive the modernization of legacy platform components with a bias toward simplicity and operational transparency
• Lead the refactoring of existing deployment pipelines to be fully Kubernetes-native
• Define and implement disciplined software release cycles using GitLab CI/CD and ArgoCD for GitOps-driven deployments
• Establish automated testing gates (unit, integration, contract) as hard requirements in the pipeline
• Mentor mid-tier developers, establish coding standards, enforce peer reviews, and reduce technical debt
• Improve engineering maturity across the team — instill a culture of instrumentation-first development where observability is never an afterthought
• Maintain and overhaul technical documentation; make it easy for new engineers to onboard and contribute
• Drive enterprise-grade infrastructure automation and orchestration using Ansible, AWX, and Terraform
• Oversee the secure and highly available architecture of core lifecycle services such as Harbor and GitLab

Requirements:

• • 8+ years of software engineering with proven technical leadership and architectural design experience
• • Full-Stack Development: Strong front-end skills (React or Vue) alongside deep back-end experience — you are comfortable owning the full request lifecycle from UI click to database
• • Observability Expertise: Deep, hands-on expertise with Grafana, Prometheus, and Loki — not just deploying them, but designing dashboards, writing PromQL/LogQL, building exporters, and enforcing instrumentation standards across a team
• • 12-Factor Mastery: Demonstrated experience auditing and refactoring real applications to be 12-factor compliant in a production environment
• • Programming: Deep expertise in Python and Go (Golang) for building distributed systems and enterprise APIs
• • Kubernetes Certification: CKA or CKAD strictly required (CNCF). Hands-on experience with on-premise clusters, preferably Rancher
• • Cloud & Infrastructure: Strong experience with OpenStack, private cloud environments, and foundational infrastructure networking
• • Automation & Tooling: Extensive experience with Ansible, AWX/Tower, Harbor, and GitLab
• • Modern Delivery: Proven expertise in SDLC practices, code refactoring, automated testing, and GitOps (ArgoCD)
• Experience designing and shipping internal developer portals or operational tooling used by platform and SRE teams
• Hands-on experience with distributed tracing (Jaeger, Tempo, or OpenTelemetry) to complement the Grafana/Prometheus/Loki stack
• Deep practical experience implementing SRE principles at large-scale enterprise
• Familiarity with Bare Metal as a Service (BMaaS) provisioning and integration
• Experience navigating ITIL change management processes within highly automated CI/CD frameworks
• Experience establishing engineering standards and driving a culture of accountability and continuous improvement