Senior Manager, Application Security

Please note that we are unable to consider applications from candidates based in France, Italy, or Germany for this role.

Money is moving onto the internet, and the shift has a name: Open Money. This is money that is open, portable, agentic, and owned by you. MetaMask spent the last ten years building it; with 100M+ downloads, users in ~190 countries, and trillions in cumulative transaction volume, it's the most trusted self-custodial financial platform on the internet. Now we're building the operating system for your money: one place to hold, move, grow, and use anything you own. Join a remote-first, global team rebuilding how money works: a problem that touches everyone, every day.

About the role

MetaMask is a self-custody wallet that does not hold users’ private keys. Blockchain transactions are generally irreversible, meaning a vulnerability in the product or its software delivery chain can lead directly to financial losses for users. As a result, MetaMask attracts sustained attention from financially motivated attackers and sophisticated supply chain actors.

We are looking for a Senior Manager, Application Security to lead application security across the MetaMask extension, mobile app, Snaps, backend services, DeFi primitives, stablecoins, and supporting smart contracts.

The role covers architecture, code, dependencies, build and release controls, security testing, and vulnerability disclosure. This is a hands-on leadership role. You will set the strategy and operating model, lead a small senior team, and remain directly involved in code review and threat modelling.

You will report to the Head of Security and work closely with MetaMask Engineering leadership to ensure security risks are understood, owned, and addressed.

Responsibilities

Leadership and planning

Lead and develop the Application Security team, including hiring, performance management and career development, while remaining directly involved in technical work.

Set the Application Security strategy, annual goals and quarterly OKRs in line with company objectives and the approved Target Operating Model. Define and track KPIs to measure performance and progress.

Report AppSec progress, coverage, remediation performance and material gaps to Security leadership and contribute to Risk Committee reporting.

Secure design and delivery

Define security review requirements across development and release, assess whether they are met and escalate unresolved risks.

Lead threat modelling and security design reviews across clients, APIs and backend services, including authentication, key management, signing and delegated actions. Assess trust boundaries across the full system and participate in architecture and RFC reviews.

Define software supply chain security requirements and work with engineering teams to implement and validate controls for dependencies, builds, artefacts and publishing.

Lead security code reviews across MetaMask applications and smart contracts, working with engineers and relevant specialists to address findings.

Define and evolve the secure development lifecycle to incorporate AI agents, including their access, actions and human review requirements. Set security standards for AI development tools, generated code and AI components in products.

Integrate security testing into development and delivery workflows, including static and dynamic analysis, dependency scanning, secrets detection and AI scanning. Evaluate tools and validate their findings.

Help engineers prevent recurring vulnerabilities through secure coding guidance, reusable libraries, training and the security champions programme.

Vulnerability management and external testing

Own application vulnerability assessment, triage, prioritisation and remediation tracking within the organisation’s vulnerability management framework. Correlate findings across clients, services and supporting infrastructure with the relevant owners to assess combined impact. Ensure findings have clear owners and deadlines, verify fixes and escalate overdue risks.

Set the scope and proposed investment for bug bounty, penetration testing and AI security scanning based on risk and results. Manage external providers, researcher relationships, rewards and payouts, and coordinate vulnerability disclosure.

Assurance and incident support