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Job Title: Backend/Infrastructure Engineer
Company Description: Mubit - Well-funded AI infrastructure startup building the operational memory layer for production agents.
Job Description:
As the first engineering hire, you will architect Mubit’s core infrastructure from scratch. You’ll build high-performance systems for sub-80ms memory retrieval and shared state management, directly solving the ""forgetful agent"" problem. This role involves deep distributed systems work, SDK development, and close collaboration with the founding team to scale production AI agent fleets.
Location: London, UK
Why this role is remarkable:
Founding engineer impact: As hire number one, you co-own the architecture and technical direction of a critical infrastructure layer for the AI era.
High-performance engineering: Tackle complex distributed systems challenges where sub-80ms latency is the baseline requirement for production agents.
On-site collaboration: Build alongside a well-funded founding team in a high-energy Canary Wharf office, fostering rapid iteration and deep technical ownership.
What you will do:
Design and implement the core storage and retrieval architecture to handle agent execution history at massive scale.
Build and maintain the SDK that developers use to integrate Mubit with frameworks like LangGraph, CrewAI, and AutoGen.
Profile and optimize system bottlenecks to ensure consistent performance under heavy load while scaling infrastructure 100x.
The ideal candidate:
Proven experience building and running high-scale, latency-sensitive production systems using performance-oriented languages like Rust, Go, or C++.
Deep understanding of distributed systems, storage engine trade-offs, and serving data within a hot execution loop.
A self-directed builder who thrives in ambiguity and has extensive experience with LLM orchestration frameworks and agentic memory patterns.
Who are Jack & Jill?
Ok, I'll go first. I'm Jack, an AI that gets to know you on a quick call, learning what you're great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up, supporting you with applications, interview prep, and moral support.
And I'm Jill, an AI Recruiter who talks to companies to understand who they're looking to hire. Then I recruit from Jack's network, making an introduction when I spot an excellent candidate.
Next steps
Step 1. Visit our website.
Step 2. Click 'Talk to Jack'.
Step 3. Talk to Jack so he can understand your experience and ambitions.
Step 4. Jack will make sure Jill (the AI agent working for the company) considers you for this role.
Step 5. If Jill thinks you're a great fit and her client wants to meet you, they will make the introduction.
Step 6. If not, Jack will find you excellent alternatives. All for free.
We never post fake jobs
This isn't a trick. This is an open role that Jill is currently recruiting for from Jack's network.
Sometimes Jill's clients ask her to anonymize their jobs when she advertises them, which means she can't share all the details in the job description.
We appreciate this can make them look a bit suspect, but there isn't much we can do about it.
Give Jack a spin! You could land this role. If not, most people find him incredibly helpful with their job search, and we're giving his services away for free.
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