Founding Technical Leader (CTO/Founding Engineer), NewCo
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25madison
US
Summary
Define and own the end-to-end system architecture while building the initial product from scratch. Lead the early engineering team and collaborate directly with the founder on technical strategy and product direction.
Job Description
Founding Technical Leader: Head of Engineering / CTO Company: Newco (Stealth)
Role: Head of Engineering / Founding Engineer (Full-Time)
Location: Flexible (US, preference for NYC)
Stage: Pre-seed (Venture Studio backed)
Comp: Significant equity + competitive cash
Who We Are
Commerce is undergoing a fundamental shift. For the past decade, ecommerce has been built around static pages, manual optimization, and fragmented tooling: from analytics to experimentation to personalization.
Newco is building the AI-native intelligence layer for DTC commerce. Our platform interprets shopper behavior from the moment of ad click, scores intent in real time, and dynamically personalizes the on-site experience without requiring brands to rebuild their infrastructure. Every interaction compounds: the system learns, adapts, and improves outcomes continuously.
The result: higher conversion, stronger retention, and a lasting edge for brands competing in a signal-scarce, AI-native world.
What You'll Do
- Define system architecture from first principles and own it end-to-end
- Build the initial product hands-on (this is a 0 to 1 role)
- Design and scale the decisioning and personalization engine across data, infra, and product layers
- Work directly with the founder on product direction and technical strategy
- Hire and lead the early engineering team as the company grows
- Communicate technical tradeoffs and system design to non-technical stakeholders in outcome-oriented terms
Who You Are
- A builder-leader at the intersection of AI, product, and real-time systems
- Experienced in high-stakes, fast-moving environments: vertical SaaS, applied ML, or personalization/recommendation systems
- Comfortable working across backend, frontend, and product, not siloed
- Strong product intuition alongside technical execution
- Thrives in ambiguity and early-stage building
Key Technical Responsibilities
- Decisioning and Personalization Architecture Design and scale the real-time scoring and routing engine: interpreting incomplete behavioral signals, making decisions under uncertainty, and serving personalized experiences with low latency.
- LLM and Agentic Systems Build and maintain AI agent layers using frameworks like LangGraph or PydanticAI, including modular reasoning pipelines (RAG, ReAct, planner-executor) for CRO automation and content decisioning.
- Data Infrastructure Integrate event-driven pipelines, vector databases (pgvector, Pinecone), and structured data stores to support real-time retrieval, persistent memory, and behavioral pattern recognition.
- Evaluation and Observability Build tools for trace inspection, confidence scoring, and output validation. Develop evaluation loops and test harnesses to ensure reliability and consistency across decisioning outputs.
- Engineering Architecture and Delivery Define technical standards, development processes, and system architecture to support a scalable, maintainable product. Partner with product leadership to translate strategy into roadmap.
Core Skills
- 5 to 7+ years of full-stack engineering experience
- Experience building real-time systems, data pipelines, or decisioning / recommendation engines
- Familiarity with LLM agent development and frameworks (LangGraph, PydanticAI, or similar)
- Production-level experience with FastAPI, Docker, and cloud-native deployment
- Comfort with vector databases and retrieval-augmented generation patterns
- Proficiency in agentic IDEs (Cursor, Windsurf, Claude Code)
Bonus (not required)
- Experience in ecommerce, marketplaces, or personalization platforms
- Familiarity with event-driven or streaming architectures (Kafka, Kinesis)
- Shopify ecosystem knowledge
What This Is Not
- Not a pure infrastructure or platform role
- Not a maintenance or scaling role
- Not joining a large existing team
You will be building the foundation.
Why Join
- Significant equity + competitive cash
- True technical ownership: define the system architecture from day one
- Backed environment: venture studio with capital, operational support, and design partners already in market
- 0 to 1 opportunity: build a company, not just write code
25madison is a venture and innovation platform: we co-found and invest in AI-native and tech-enabled businesses, supporting our startups with deep connectivity to customers, design partners, and a broad array of services spanning product design, engineering, data science, branding, infrastructure and more. 25madison is backed by Apollo Global Management.
We partner with Private Equity firms and their portfolio companies for business transformation, connecting incumbent companies with the next disruptors to catalyze PE Firm and portfolio company value creation.
Building:
We focus on building businesses across Healthcare, Supply Chain & Industrials, and AI-driven B2B software. We combine technical and functional expertise, real-time innovation, and the institutional resources of our private equity partners.
Investing:
We invest in Pre-Seed to Series A category-defining startups in B2B software and healthcare, leveraging decades of institutional venture experience and a team of hands-on operators.
Transformation:
We future-proof private equity firms and portfolio companies by harnessing AI technology to unlock transformative value.
Creative:
Our in-house agency, Creature, is a leading brand, marketing, and UX partner that works with companies at defining moments. Together, we create impactful brand experiences that deliver immediate impact and long-term equity.
Founded
2018
Company size
11-50 employees
Industry
Venture Capital and Private Equity Principals
Org type
Privately Held
Headquarters
New York, NY
25madison is a venture and innovation platform: we co-found and invest in AI-native and tech-enabled businesses, supporting our startups with deep connectivity to customers, design partners, and a broad array of services spanning product design, engineering, data science, branding, infrastructure and more. 25madison is backed by Apollo Global Management.
We partner with Private Equity firms and their portfolio companies for business transformation, connecting incumbent companies with the next disruptors to catalyze PE Firm and portfolio company value creation.
Building:
We focus on building businesses across Healthcare, Supply Chain & Industrials, and AI-driven B2B software. We combine technical and functional expertise, real-time innovation, and the institutional resources of our private equity partners.
Investing:
We invest in Pre-Seed to Series A category-defining startups in B2B software and healthcare, leveraging decades of institutional venture experience and a team of hands-on operators.
Transformation:
We future-proof private equity firms and portfolio companies by harnessing AI technology to unlock transformative value.
Creative:
Our in-house agency, Creature, is a leading brand, marketing, and UX partner that works with companies at defining moments. Together, we create impactful brand experiences that deliver immediate impact and long-term equity.
Founded
2018
Company size
11-50 employees
Industry
Venture Capital and Private Equity Principals
Org type
Privately Held
Headquarters
New York, NY