Founding Engineer

Jack & Jill/External ATS; Greater London; On-site; GBP 90,000 - 110,000; Full time

Job summary

A high-growth AI-native fintech startup is seeking a Founding Engineer to build a core financial operations platform from scratch. This unique role includes true founding-level ownership and equity opportunities, allowing you to construct multi-tenant systems for AI-driven financial workflows. The ideal candidate is a senior engineer with experience in AI product development and a proven record of building innovative products. This position offers the chance to work closely with founders, contributing to both architectural decisions and product direction.

Benefits

Equity in a high-growth startup

Work with industry advisors

Meaningful project impact

Qualifications

• Hands-on experience shipping AI-enabled products.
• Proven track record of building zero-to-one products or early-stage systems.
• Pragmatic systems thinker thriving in high-autonomy environments.

Responsibilities

• Build the core platform end-to-end, including backend APIs and frontend integration components.
• Design and implement multi-tenant agentic workflows using LLMs as core infrastructure.
• Partner directly with founders on architecture, product trade-offs, and technical strategy.

Skills

Senior full-stack or backend-leaning engineering

Experience in AI-enabled products

Building zero-to-one products

Designing API-first systems

Technical strategy collaboration

Job description

Founding Engineer (AI × Fintech)

Salary: £90k-£110k + Equity

Company Description: AI-native fintech infrastructure startup

Job Description: As the Founding Engineer, you will build the core agentic financial operations platform from the ground up. You will design API-first, multi-tenant systems that allow partner platforms to embed white‑label AI agents for automated financial workflows. This is a high‑ownership role working directly with founders to set the engineering foundations and product direction.

Location: London, UK

Why this role is remarkable:

• True founding‑level ownership with meaningful equity in a high‑growth AI‑native fintech.
• Backed by senior industry advisors from global payment giants and top‑tier fintech companies.
• Massive surface area to build production‑grade AI agent systems rather than simple experiments.

What you will do:

• Build the core platform end‑to‑end, including backend APIs and frontend integration components.
• Design and implement multi‑tenant agentic workflows using LLMs as core infrastructure.
• Partner directly with founders on architecture, product trade‑offs, and technical strategy.

Ideal candidate:

• Senior full‑stack or backend‑leaning engineer with hands‑on experience shipping AI‑enabled products.
• Proven track record of building zero‑to‑one products or early‑stage systems in production.
• Pragmatic systems thinker who thrives in high‑autonomy environments without heavy process.

Next steps

1. Visit our website.
2. Click 'Talk to Jack'.
3. Talk to Jack so he can understand your experience and ambitions.
4. Jack will make sure Jill (the AI agent working for the company) considers you for this role.
5. If Jill thinks you're a great fit and her client wants to meet you, they will make the introduction.
6. If not, Jack will find you excellent alternatives. All for free.