Founding Engineer

About

About Spring AI

Spring is an AI-native lender. The team spent the first eight months of the business building completely novel in-house software: loan management systems, payment rails infrastructure, and technology for analyzing business bank transactions and financials. That foundation enabled Spring to raise over $100 million in funding for CPG brands within its first year. Spring is now building the product that all of that infrastructure was designed to power: an AI CFO agent. The addressable market starts with tens of thousands of CPG brands and extends to small businesses across many verticals. The lending operation gives Spring a unique advantage: deep financial data, direct customer relationships, and the real-world workflows that agents need to automate. The CFO agent operates across a brand's entire financial stack: managing deductions, handling email workflows, working with accounting and banking data, and more. The interface is a core part of the product. The agent renders an opinionated, flexible UI that mutates in real time, displaying actions, visualizations, and interactable elements through LLM tool calls. Inspired by the architecture of tools like Claude Code, the agent uses its own outputs to continuously improve.

About the role

Spring is hiring a Founding Engineer to work primarily on the new AI CFO agent. The team is 9 people total, with 2 current developers (Oliver and Lucas, both with high-frequency trading backgrounds). A third engineer just accepted a trial offer. There is no dedicated product person, so whoever joins will have an outsized impact on what gets built and how. This role is tech-lead-level autonomy from day one. You will own and deliver on the agent's tool surface and trajectory quality, ramp up quickly without spoon-feeding, and operate as a self-sufficient builder. The time split is approximately 75% for new AI agent work and 25% for the existing lending infrastructure. The role is primarily backend Python, with exposure to TypeScript frontend development. No customer-facing work or formal product ownership is expected. You will be in the trenches building, but you will be socialized and excited about the product, not just talking to a database in a corner.

What you'll own

• Build and extend the AI CFO agent's tool surface so it can complete tasks that currently take a CFO or CEO an hour or more
• Improve agent trajectory quality, breadth, and depth of tools so the agent reliably ships magical, end-to-end outcomes
• Compose existing scoped tools and build new ones (email composition, document filling, payload generation, account integrations)
• Contribute to the underlying infrastructure that both the lending business and the AI agent business sit on top of
• Operate as a tech lead from day one: ramp fast, own delivery, work in a Slack-native, AI-tool-heavy development cycle

Requirements

Must-have

• New grad to 5 years of engineering experience (hard cap at 5 years)
• Excellence signal: notable startup background, big tech background, or top university CS / technical degree
• Strong Python backend fundamentals: APIs, async, databases, cloud deployment
• AI-native daily usage of Claude Code, Codex, or comparable agentic coding tools, with strong opinions on how to make agent systems better
• Self-motivated tech lead profile: ramps fast, works with minimal scaffolding, comfortable owning ambiguous scope

Nice-to-have

• Full-stack experience with TypeScript on the frontend
• Prior zero-to-one startup experience with a clear story and demonstrable users
• High-frequency trading or quantitative engineering background (matches current team profile)
• Excited about UX and product, not just systems

Benefits & perks

• Meaningful equity

Interview process

1. 1Application review
2. 2First Round
3. 3Second Round, Technical
4. 4On-Site
5. 5Offer Extended
6. 6Hired