Spring AI — Founding Engineer

davidjoseph-co; New York (NY); On-site; USD 175,000 - 250,000; Full time

Job summary

Spring AI is hiring a Founding Engineer to build the AI CFO agent and own core backend work in NYC. You will work with a small team, 75% on AI agent development and 25% on lending infrastructure, with tech-lead autonomy from day one. Primary backend Python with TypeScript frontend exposure; no customer-facing duties.

Ideal candidates bring 0–5 years of engineering experience, strong Python skills, and AI-native tools experience (Claude Code or Codex); in-person in NYC is required.

Qualifications

• 0–5 years engineering experience, hard cap at 5
• Strong Python backend fundamentals
• AI-native experience: Claude Code or Codex
• NYC in-person requirement

Responsibilities

• Build and extend the AI CFO agent's tool surface to enable CFO/CEO-level tasks
• Improve agent trajectory quality and tool coverage to ensure end-to-end delivery
• Compose and extend existing tools; develop new ones (email drafting, document filling, payload generation, integrations)
• Contribute to underlying infrastructure for both lending and AI agent platform
• Operate as tech lead from day one with fast ramp and delivery in a Slack-native AI-tool-driven workflow

Skills

Python backend fundamentals

Self-motivated tech lead

Startup/big tech background signal

Collaboration

Tools

Claude Code

Codex

TypeScript

Job description

Spring AI — Founding Engineer

Type: Full-time | On-site | New York City, NYCompensation: $175,000–$250,000 + Meaningful equity (no specific % stated)Hiring count: 1Visa sponsorship: None availableReports to: Oliver, CTO / Founder (LinkedIn not provided)

About Spring AI

Spring is an AI-native lender. Its first eight months were spent building novel in-house software — loan management systems, payment rails infrastructure, and tooling to analyze business bank transactions and financials — a foundation that let it originate over $100M in funding to CPG brands within its first year. Spring is now building the product that infrastructure was designed to power: an AI CFO agent that operates across a brand's entire financial stack (deductions, email workflows, accounting and banking data). The agent renders an opinionated, real-time-mutating UI through LLM tool calls and, inspired by Claude Code's architecture, uses its own outputs to continuously improve.

Founded: 2025 | Team size: 9 (Series A) | Total funding: not statedIndustry: FinTechWebsite: spring.aiOffice: New York City, NY

Why Candidates Should Join

• Outsized ownership: No dedicated product person — whoever joins shapes what gets built and how, with tech-lead autonomy from day one.
• Real data moat: The lending business supplies deep financial data, direct customer relationships, and the real-world workflows the agent automates.
• Frontier agent work: ~75% of time on a self-improving AI CFO agent inspired by Claude Code; ~25% on the lending infrastructure underneath.

Intake Call Summary

• No intake call transcript available — the Contrario page provides an intake video only (not transcribed). See flags in chat.

The Role

Founding Engineer working primarily on the new AI CFO agent, with tech-lead-level autonomy from day one. The team is 9 people, with 2 current developers (Oliver and Lucas, both ex-HFT); a third engineer just accepted a trial offer. Time split 75% new AI agent work / 25% existing lending infrastructure. Primarily backend Python with TypeScript frontend exposure. No customer-facing work or formal product ownership expected.

What You'll Be Doing

• 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, and the breadth and depth of tools, so the agent reliably ships 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 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

Tech stack: Python (backend — APIs, async, databases, cloud deployment); TypeScript (frontend); LLM tool-calling / agentic systems

Requirements

• 0-5 years engineering, hard cap at 5
• Excellence signal: notable startup, big tech, or top university CS
• Python backend fundamentals
• AI-native: Claude Code, Codex daily
• Self-motivated tech lead, ramps fast
• NYC in-person

Green Flags

• Notable startup or big tech background showing the candidate cleared a real bar to get in (high-clout internships count). Confirms execution under pressure.
• Top university CS or technical degree paired with active engineering signal (GitHub, side projects, hackathon wins).
• Quant or HFT engineering background. Matches the existing team profile (both current devs are ex-HFT).
• AI-native daily usage of Claude Code, Codex, or comparable. Has strong opinions on agent tool design.
• Socialized, high-energy engineer who is excited about the product, not just a backend dev who wants to talk only to a database.

Red Flags

• Indie-dev-only background without notable startup, big tech, or top university signal. Hard to differentiate from low-clout AI-note-taker-tier work.
• More than 5 years of experience.
• Zero-to-one experience but no users, no story to tell, no demonstrable shipping signal.
• Resume polish without excellence markers: mid-university + unrelated experience + no notable inflection point.
• Wants spoon-feeding or detailed scope handoff. Cannot operate as tech lead from day one.

Role Details

Salary$175,000–$250,000EquityMeaningful (no specific % stated)On-site policyNYC in-personVisa sponsorshipNone availableEmployment typeFull-timeLocationNew York City, NY

Screening Questions

• None provided on the Contrario role page. See flags in chat.

Interview Process

Stage 1 — Pending Approval — Candidates awaiting initial approval.Stage 2 — First Round with Oliver (CTO / founder) — Initial interview with the CTO/founder.Stage 3 — Second Round, Technical — Shared-screen system design + implementation. One ambiguous problem, ~15 min verbal design discussion, then implementation. Not algorithms-heavy.Stage 4 — On-Site — 3-hour on-site in NYC.Stage 5 — Offer ExtendedStage 6 — Candidate Hired — Candidate accepts and starts.

Ideal Companies & Backgrounds

• Not provided on the Contrario role page.

Ideal Candidate Profiles

• Not provided on the Contrario role page.

Rejected Candidate Feedback

• Not provided on the Contrario role page.