[Hiring] Lead Application Security Engineer @The French Sourcer

Role Description

Be the first security engineer on a platform that moves customer data for hundreds of enterprises, where tenant isolation is a problem you solve in the code and the roadmap is yours to write.

• Owning application security end to end as the first dedicated security hire, reporting to the VP of Engineering, while the engineering team roughly doubles in size.
• Spending most of your week in the codebase, reading and writing production TypeScript and Go, and shipping security fixes yourself.
• Threat modeling new products and major redesigns early, while design choices are still cheap to change, and hardening them before they reach customers.
• Designing sub-tenant access control for multi-team and multi-brand customers who need different levels of access to configuration and data inside the same account.
• Improving rate limiting, abuse detection and the granularity of access control on internet-facing APIs that serve customer data at high volume.
• Extending a multi-region, multi-cloud backend into new regions so global customers can meet their data residency requirements, with security designed into each launch.
• Building your own roadmap: looking at the architecture, finding the highest-leverage problems and going after them, with the autonomy that comes with being the first person in the role.

Qualifications

• A real background as a backend software engineer: you wrote production code (APIs, distributed systems, data pipelines) inside a product codebase before or alongside your move into security.
• 6+ years in security engineering with deep distributed systems knowledge, enough to understand what product teams are building and influence it from a place of trust.
• Experience as an early security hire (first 1 to 3) at a SaaS or data infrastructure company, plus 2+ years at a venture-backed or high-growth company as it went through real scale.
• Staff or Lead level today, reached through promotions over tenures of 2 years or more.
• Hands-on experience securing multi-tenant platforms (tenant isolation, authorization models) and systems that span several clouds or regions.
• A degree in Computer Science, Math, Physics or a similar field, and the ability to explain a design clearly and stay precise under deep technical questions.
• Bonus: privacy-adjacent security work, having designed or secured data infrastructure as an early engineer, or experience at a security-focused company.

Requirements

• Fluent in English (professional level).

Benefits

• Competitive equity and benefits.
• Remote within Canada.

Company Description

A late-stage B2B data and AI company, backed by top-tier investors, whose platform helps businesses turn their customer data into personalized marketing, with a growing part of that work now driven by AI agents. Revenue and headcount have been growing fast year over year, and hundreds of companies rely on the platform in production. Several hundred people, fully remote, with an engineering culture that holds a very high bar for quality and simple, scalable software. This is the company's first dedicated security role: it reports to the VP of Engineering and works across every product team.