Software Engineer, Security

About the role

About Slash

Slash is building the future of business banking, one industry at a time. We believe businesses deserve financial infrastructure tailored to how they actually operate. That's why we're creating a new category of business banking. We combine the reliability of traditional banking (high yields, competitive rewards, and comprehensive security) with industry-specific features that make businesses more efficient, more competitive, and more profitable.

Started in 2021, Slash is one of the fastest growing fintechs in the world and we power over ten billion dollars a year in business purchasing across numerous industries. We recently raised a $100M Series C led by Ribbit Capital with participation from Khosla Ventures, Goodwater Capital, NEA, and Y Combinator, accelerating our expansion into new markets and products.

Slash is headquartered in San Francisco, and has a strong in-person culture.

About the role This is a hands-on engineering role focused on security: you’ll build and ship changes to our application and infrastructure, not just assess risk or coordinate fixes. We're looking for a Software Engineer to own and scale the security of our platform as we grow fast. You'll be responsible for keeping our systems secure across the entire stack — from network and infrastructure to application-level security — while establishing the patterns and guardrails that let the rest of the team move quickly without having to worry about security. You'll define and own our security program end-to-end, and play a key role in enabling Slash to serve billions of dollars in business spend reliably and securely.

What you'll do • Own Slash's security program end-to-end — find gaps, prioritize, and propose and drive changes independently • Work on network security: manage and harden our Cloudflare implementation, AWS WAF, VPC networking, and overall infrastructure posture • Work on application security: ship features like passkey authentication, SMS rate limiting, and other product-level hardening • Manage recurring pen tests and our bug bounty program, and coordinate remediation across engineering • Assist on compliance efforts like PCI and SOC 2 • Establish security patterns, tooling, and guardrails that enable the rest of the team to move fast safely • Own corporate IT security, including keeping company equipment and endpoints secure • Interface with customers, internal stakeholders, and key vendors to answer questions and provide confidence in Slash's security practices

We're looking for someone who • Is a software engineer first — has experience building and shipping production software in TypeScript or another programming language, and wants to apply those skills to security. Doesn’t just identify gaps or recommend fixes; writes the code and owns the implementation. • Has broad security knowledge across application code and infrastructure, and is comfortable reading, debugging, and changing the systems they’re securing. Our stack includes Kubernetes/EKS, CockroachDB, Kafka, Terraform/Pulumi, and AWS. • Can independently identify security gaps, prioritize them based on risk, and drive high-impact improvements through to production without waiting to be told what to work on. • Is organized and able to coordinate pen tests and audits, manage competing security priorities, and ensure findings get resolved