Senior / Staff Backend Engineer (+ Equity) at Fast-growing AI FinTech startup

Jack and Jill AI; Greater London; On-site; GBP 70,000 - 90,000; Full time

Job summary

An innovative AI FinTech startup in London seeks a Senior / Staff Backend Engineer to design and implement capabilities for autonomous frameworks, develop data pipelines, and create scalable APIs. The ideal candidate has at least 4 years of software engineering experience, deep expertise in Python and FastAPI, and a track record in high-velocity environments. This is a high-impact opportunity to shape the technical vision of a fast-growing venture with substantial equity potential.

Qualifications

• 4+ years of software engineering experience at a venture-backed startup or top-tier technology firm.
• Deep technical expertise in Python, FastAPI, and distributed systems.
• Proven track record of taking complex products from ideation to production.

Responsibilities

• Design and implement new capabilities for autonomous agentic frameworks.
• Build and maintain scalable data pipelines for complex documents.
• Develop performant APIs and distributed systems for decision-making engines.

Skills

Python

FastAPI

Distributed systems

Postgres

ElasticSearch

Message queues

Job description

Senior / Staff Backend Engineer

Company Description

Fast-growing AI FinTech startup

Job Description

You will join a lean, ambitious team building a category-defining AI operating system for private capital markets. As a senior engineer, you will own features from conception to production, designing robust backend services and agentic frameworks that help top-tier investment firms process complex data and unlock deeper financial insights at scale.

Location

London, UK

Why this role is remarkable

• Work directly with a founding team backed by top-tier VCs and industry executives from leading global investment firms.
• Massive growth trajectory with significant product-market fit and a rapidly expanding international customer base in the US and Europe.
• High-impact opportunity to shape the technical vision of an ultra-growth venture while participating in substantial equity upside.

What you will do

• Design and implement new capabilities for an autonomous agentic framework to achieve human-level analytical expertise.
• Build and maintain scalable data pipelines for ingesting, processing, and indexing large volumes of complex documents.
• Develop performant, streaming-first APIs and distributed systems that power the core platform's decision‑making engine.

The ideal candidate

• 4+ years of software engineering experience at a venture‑backed startup or top-tier technology firm.
• Deep technical expertise in Python, FastAPI, and distributed systems like Postgres, ElasticSearch, and message queues.
• Proven track record of taking complex products from ideation to production in a fast-paced, high‑velocity environment.