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, network policies) in environments like EKS or GKE.
• Familiarity with BI and data exploration tools like Looker and Snowflake for building security metrics and dashboards.
• Experience building or operating security exception/risk acceptance workflows at scale.
• Familiarity with cloud networking and network segmentation strategies.
• Ability to work well cross-functionally and communicate with audiences who may not have a security or engineering background.
• Experience supporting multi-business-unit organizations with varying compliance and regulatory requirements.

We’re working to build a more inclusive economy where our customers have equal access to opportunity, and we strive to live by these same values in building our workplace. Block is an equal opportunity employer evaluating all employees and job applicants without regard to identity or any legally protected class. We will consider qualified applicants with arrest or conviction records for employment in accordance with state and local laws and “fair chance” ordinances.

We believe in being fair, and are committed to an inclusive interview experience, including providing reasonable accommodations to disabled applicants throughout the recruitment process. We encourage applicants to share any needed accommodations with their recruiter, who will treat these requests as confidentially as possible. Want to learn more about what we’re doing to build a workplace that is fair and square? Check out our I+D page.

While there is no specific deadline to apply for this role, U.S. roles are typically open for an average of 55 days before being filled by a successful candidate. Please refer to the date listed at the top of this job page for when this role was first posted.