Founding Engineer - Co-Founder Path & Equity

Jack & Jill; Greater London; On-site; GBP 136,000 - 184,000; Full time

Benefits offered by this job

Co-founder path

Equity milestones

Privacy-first engineering

Job summary

Jack & Jill in London is seeking a Founding Engineer to own the core personal memory engine end-to-end. You will architect and ship a local-first, encrypted storage system that lets AI learn and retain context for users. This is a rare chance to progress toward a co-founder role at a high-growth startup.

You will drive infrastructure from scratch, work on embedded databases and cryptographic designs, and have opportunities for significant equity based on milestones and performance.

Qualifications

• Proven Go production-grade system experience.
• Strong background in building scalable infrastructure.
• Demonstrated builder mindset with shipped systems.

Responsibilities

• Architect and build the memory engine 2.0 from scratch.
• Design local-first, encrypted storage models emphasizing user privacy.
• Optimize performance for millisecond retrieval under real-world load.

Skills

Go systems

High-performance infra

Builder mindset

Tools

Embedded databases

Vector stores

Graph stores

Zero-knowledge crypto

Job description

Jack & Jill in London is seeking a Founding Engineer to own the core personal memory engine end-to-end. You will architect and ship a local-first, encrypted storage system that lets AI learn and retain context for users. This is a rare chance to progress toward a co-founder role at a high-growth startup.

You will drive infrastructure from scratch, work on embedded databases and cryptographic designs, and have opportunities for significant equity based on milestones and performance.