Founding Engineer

The Role We’re hiring our first Founding Engineer — someone who will work alongside the founder to build Multifactor’s platform from the ground up and shape the technical foundation of the company. This is not an “early employee” role where you slot into an existing codebase and pick up tickets. You’ll be writing core infrastructure for systems that must be correct-by-construction, making architectural decisions that the next 10+ engineers will inherit, and turning peer-reviewed cryptographic research into production software that enterprises and consumers trust with their most sensitive accounts. Few roles offer this much leverage over a product that could secure millions of accounts across the agentic web. What You’ll Do Ship production code daily across Multifactor’s full product surface — backend services, APIs, browser extensions, and client applications. Own entire features end-to-end. Take a problem (sometimes from a research paper, sometimes from a customer call) and turn it into production software. You’ll have the autonomy to shape what gets built and how. Work directly with the founder (CEO) to translate research breakthroughs into production‑grade software, making architecture, threat modeling, and product decisions together. The feedback loop is measured in hours, not sprints. Build the security layer for the agentic web. Design and implement systems that prevent prompt injection, credential theft, confused‑deputy attacks, and cross‑agent hijacking — problems most companies haven’t even started thinking about. Lay the engineering foundation. Your code, your tooling choices, your patterns for CI/CD, testing, and incident response will shape how this team operates for years. That’s a rare opportunity to define an engineering culture from scratch around a mission that matters. Who You Are 4–8 years of software engineering experience, with production systems that people depend on. A hands‑on builder first. You write and ship features yourself. You’ll spend most of your time in the codebase, delivering production code. This role leads from the front. Strong across the stack. You’re comfortable with backend systems (APIs, services, data stores) and can build competent frontend when needed. You care about shipping the whole feature, not just your piece of it. Security‑conscious by instinct. You think about threat models before feature specs. Experience with authentication protocols (OAuth, FIDO2, WebAuthn), key management, or applied cryptography is a strong signal. Comfortable with ambiguity. Seed‑stage means the roadmap changes. You can hold multiple priorities, make tradeoffs with incomplete information, and still ship. Fast and rigorous. You write code quickly without cutting corners on correctness. When your platform secures people’s bank accounts and enterprise systems, precision isn’t optional — it’s the mission. A clear communicator. You can explain a technical decision to a non‑technical person and review a cryptographic protocol with a PhD. Both happen here. Nice to Have Experience building browser extensions, secure enclaves, or isolated execution environments. Familiarity with cryptographic libraries or protocols (TLS, post‑quantum algorithms like CRYSTALS‑Kyber/Dilithium, lattice‑based schemes). Background in ML infrastructure, particularly related to AI agent systems or anomaly detection. Previous experience at a seed or Series A startup where you were one of the first 5 engineers. Contributions to open‑source security tools or published security research. Experience building systems where correctness is non‑negotiable — financial infrastructure, healthcare, defense, critical infrastructure. Comfort across TypeScript/JavaScript, Python, Rust, cloud infrastructure (AWS/GCP), browser extension APIs, and relational databases. Compensation & Benefits Salary: $145,000 – $195,000 Equity: 0.50% – 2.00% Unlimited PTO with a culture that actually encourages using it Wellbeing & professional development reimbursements Commuter benefits for getting to our SF office Employer‑sponsored retirement savings (401k w/ matching) Employer‑sponsored dental, vision, health, and life benefits #J-18808-Ljbffr Multifactor (YC F25)