Senior Security Engineer, Platform Security

Block builds simple, powerful tools that make progress towards an economy that’s truly open to all. Each of our brands unlocks different aspects of the economy for more people. Square makes commerce and financial services accessible to sellers. Cash App is the easy way to spend, send, and store money. Afterpay is transforming the way customers manage their spending over time. TIDAL is a music platform that empowers artists to thrive as entrepreneurs. Bitkey is a simple self-custody wallet built for bitcoin. Proto is a suite of bitcoin mining products and services. Together, we’re helping build a financial system that is open to everyone. Join us. The Role The Platform Security team is responsible for securing Block's cloud, compute, and network infrastructure across multiple business units including Square, Cash, and Afterpay. We discover, track, and enable the business to remediate the most critical security risks across Block's cloud ecosystems (AWS and GCP). We drive the creation of cloud security policy and best practices, measure and aggregate deviations from these policies, and develop capabilities to estimate security risk based on cloud signals and business context. This work drives Block's cloud security strategy and is the lens through which Block measures progress of our cloud security posture over time. We believe that the secure option should be the easiest option for our users. We're looking for a strong Senior Platform Security Engineer with a deep understanding of securing cloud infrastructure and services at scale to help us execute on this vision. You Will Architect and evolve cloud security guardrails. Design and implement SCPs, GCP org policies, and IAM controls that shape how Block uses cloud infrastructure for years to come. Build automation to discover, measure, and contextualize security issues. Develop integrations with CSPM/DSPM tools and internal platforms to surface and prioritize findings. Own the cloud security exception lifecycle. Build and maintain the tooling and processes that allow teams to request, review, and track security exceptions at scale Partner with platform teams to deliver solutions that permanently eliminate entire categories of cloud security risk. Deliver key cloud security assurance functions. Balance the need to remediate critical misconfigurations and sensitive data exposures with being responsible stewards of our developers' time. Develop risk-based prioritization. Build data pipelines and dashboards that aggregate security signals and help leadership understand posture trends. Respond to and triage cloud security alerts. Support on-call rotations, investigate findings, and help engineers resolve issues quickly. Produce quality software that stands the test of time and scales across Block's multi-cloud footprint. Think, build and iterate in an AI-augmented environment. You Have 5+ years of experience as a software or security engineer 4+ years of experience securing infrastructure running on AWS and/or GCP at scale. Deep experience with Infrastructure-as-Code. Terraform (including securing Terraform pipelines), SCPs, GCP org policies, and understanding of best practices and pitfalls when deploying guardrails at organizational scale. Experience with cloud security posture management (CSPM) tools such as Wiz, and familiarity with DSPM concepts (sensitive data discovery, classification, and remediation). Strong understanding of IAM. AWS IAM policies, roles, SCPs, permission boundaries; GCP IAM, service accounts, and org-level constraints. Experience maturing the cloud security posture of large, complex, multi-account/multi-project environments. Demonstrated ability to successfully deliver complex, multi-faceted projects from concept to launch. Demonstrated fluency with AI-assisted development tools (e.g., Claude Code, Cursor, GitHub Copilot, or similar agentic coding tools) in real production work Bonus If You Have Experience with Kubernetes security (pod security policies, net