Senior Software Engineer - Job Description Notes

The Pitch: Why is Prefactor Exciting?

• Define a New Category: You'll be building foundational infrastructure for AI agents, essentially the "Okta for Agents."

• Solve Unanswered Questions: This is a rapidly evolving, undefined space. You will be at the forefront, contributing to what could become the new industry standard for interaction and automation via Model Context Protocol (MCP).

• Build in a Moving-Target Environment: The MCP spec is fast-moving. This role requires an experienced, pragmatic, and passionate engineer who thrives on technical challenges and innovation.

Outcomes & Key Responsibilities

• End-to-End Ownership: Independently design, build, and deploy a completely new, major feature of the product from scratch. You will leave a significant personal stamp on the product.

• Become the Expert: Develop deep expertise in core areas of our system, becoming the go-to person for those components.

• Technical & Cultural Contributor: Actively contribute to the overall technical strategy and help shape a culture of innovation, speed, and quality. Be the engineer the team can't imagine building Prefactor without.

• Some Examples of things you can build with us:

  • Model and build complex workflows for agent authorisation.

  • Develop a robust audit system to monitor all agent activity.

  • Engineer systems for ingesting, processing, and securely storing large datasets.

  • Build and manage a highly stable and scalable decision and authorisation engine.

Ideal Candidate Profile & Experience

• Stage-Appropriate Skillset: Thrives in early-stage, small-team environments. Comfortable making decisions with autonomy, fixing what you've built, and building for the future. Crucially, you’ll help us focus on building what’s essential now, vs what’s still a great idea but something that we can build later.

• Proven Backend Product Experience: You have a significant track record of building complex, back-end-heavy products. You simplify complexity and communicate it effectively.

• Project Ownership: Demonstrable experience owning projects end-to-end, from ideation to deployment and stakeholder management. You have a history of making things demonstrably better.

• Pragmatic & Skeptical: You are a seasoned, pragmatic engineer who provides a healthy pushback on assumptions and isn't swayed by hype 

Technical Skillset

• Ideal: Experience with Elixir and an interest in the MCP space.

• Required Back-End Experience: Strong proficiency in one or more back-end languages like Go, Ruby, Scala, Rust, or similar. A mixed experience is highly valued.

• Cloud & Infrastructure: Hands-on experience with AWS. You've had responsibility for deploying and managing applications and infrastructure.

• Containerization: Proficient with Docker.

• Confident with JavaScript and building UIs

Senior vs. Mid-Level Differentiators for This Role

• Seniors will:

  • Discover, prioritize, estimate, and communicate their own work.

  • Own projects end-to-end without being spoon-fed tasks.

  • Communicate challenges clearly and build consensus on technical decisions.

  • Consistently deliver high-quality output and are not defensive about feedback.

• Mids will:

  • Exhibit the same traits but will typically own component parts of a larger project rather than the entire initiative.