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

Build security guardrails across our infrastructure. Design and deploy controls for cloud resources, compute workloads, and network traffic across AWS, GCP, and hybrid environments.
Strengthen cloud security. Improve IAM and organization-level policies, automate the discovery and prioritization of misconfigurations and sensitive data exposures, and evolve security exception workflows.
Secure workloads from build to runtime. Improve Kubernetes and container isolation, protect CI/CD secrets and permissions, and strengthen image signing and software supply chain controls.
Protect service connectivity. Develop network segmentation, ingress and egress policies, firewall controls, and edge protections that reduce exposure while supporting business needs.
Write and operate production software. Build tested, maintainable services, integrations, and infrastructure-as-code that make security controls reliable and manageable at scale.
Partner with platform and application teams to embed secure defaults into shared infrastructure and eliminate recurring categories of risk.
Use security findings, operational telemetry, and business context to prioritize improvements and measure their effectiveness.
Participate in the Platform Security on-call rotation, troubleshoot issues across infrastructure layers, and turn recurring support needs into automation and self-service capabilities.
Lead projects from design through rollout, document technical decisions, and share expertise through mentoring and engineering reviews.

You Have

8+ years of experience as a software, infrastructure, or security engineer, including 4+ years securing production infrastructure at scale.
Hands-on experience securing production infrastructure in AWS and/or GCP.
Deep expertise in infrastructure security, with the ability to apply your knowledge across unfamiliar systems and technologies.
A solid understanding of infrastructure security fundamentals, including least privilege, workload isolation, network segmentation, and secure service communication.
Strong programming skills in Python, Go, or a similar language, with experience building and maintaining production tooling or services.
Experience using Terraform or similar infrastructure-as-code tools to manage controls through reviewed, tested, and staged changes.
Demonstrated ability to deliver complex projects and make practical tradeoffs between security risk, reliability, and developer experience.