Staff Platform Security Engineer (Security)

Phantom is on a mission to connect the world to the freedom of open markets. Tens of millions of people all over the world use Phantom to access global markets that never close, including perpetuals, prediction markets, tokenized assets, stablecoins and memes. Phantom users are able to discover the markets that matter and the cultural moments that shape them, building conviction through real-time data and the verified performance of top traders. With self-custody and access to open networks at its core, Phantom lets them control their financial moves in the same app they use to safely store or spend money worldwide. Phantom has reached #1 in Google Play's finance category and consistently ranks in the top 50 apps across all categories. Phantom partners with many of the most trusted and influential names in finance like Hyperliquid, Stripe, Kalshi and Visa, to make the most popular and innovative financial products accessible to everyone. We are around 180 people, fully remote, backed by a $150M Series C investment from a16z, Sequoia Capital and Paradigm. Platform security is foundational to protecting Phantom and the systems our users rely on. We’re hiring a Senior Platform Security Engineer to own and improve security across our AWS and Kubernetes environments. You’ll work directly with infrastructure and engineering teams to secure the control planes, identities, workloads, and deployment systems behind our most critical products. We’re building an AI-native security team that aggressively uses AI to expand the speed, depth, and reach of our work. We’re looking for a strong security engineer with high agency who can identify the risks that matter, build practical controls, and own problems through verified remediation. This is a hands-on role for someone who is comfortable working in production systems, writing code and infrastructure, responding to incidents, and making security improvements without slowing down the teams building on the platform. This role is fully remote; however, we’re only open to candidates based in the US and Canada. Responsibilities • AWS Security: Own and improve security across Phantom’s multi-account AWS environment, including IAM, Identity Center, networking, compute, storage, secrets, logging, and organization-level guardrails. • Kubernetes Security: Secure production Kubernetes environments running on Amazon EKS, including cluster configuration, workload identity, RBAC, admission controls, network boundaries, secrets, container security, and tenant isolation. • Identity and Access: Design least-privilege access models for engineers, services, and automation. Build scoped, auditable, and time-bound access paths for sensitive production systems. • Mission-Critical Systems: Protect the infrastructure supporting products and services that handle sensitive data and high-value operations. • Cloud Security Architecture: Lead security design for new infrastructure, platform services, and major architectural changes. • Infrastructure and Policy as Code: Build reusable security controls using tools such as Pulumi, Terraform, Kubernetes policy engines, and automated configuration validation. • CI/CD and Supply Chain Security: Harden build, deployment, and release systems, including GitHub Actions, workload federation, build runners, dependencies, artifacts, signing, provenance, and access to production environments. • Security Automation: Build tools that identify and remediate cloud and Kubernetes risks at scale. Apply AI-assisted workflows where they materially improve analysis, coverage, or response speed. • Cross-Functional Leadership: Partner closely with Infrastructure, SRE, Developer Experience, and product engineering