Senior Software Engineer ($250K - $300K + Equity) at YC-backed AI Data Infrastructure Startup

About the job

Job Title: Senior Software Engineer

Salary: $250K – $300K base + competitive equity (OTE up to $400K)

Company Description: YC W25 AI data infrastructure startup, SF, 8-figure revenue with hockey-stick growth

Job Description: Join a 20-person team that is pushing the frontier of LLMs and AI agents through novel datasets and infrastructure. This company works with all 5 leading AI labs and is becoming the go-to data infrastructure partner across the AI ecosystem. They have sharp hockey-stick revenue growth, a talent-dense founding team from top quantitative finance and investment banking backgrounds, and are expecting a $20-30M Series A shortly. As a Senior Software Engineer focused on core infrastructure, you will own the foundational systems that power everything, mentor junior engineers, and shape the architecture from day one.

Location: San Francisco, CA (FiDi), flexible in-office with most engineers coming in Monday through Friday

Why this role is remarkable:

• Build the core infrastructure that directly powers frontier data creation for the hardest agentic and reasoning workflows across all 5 leading AI labs, working on problems that are genuinely non-commodity and at the cutting edge of what AI can do
• Join at the earliest stage of a YC W25 company with $3M raised at a $40M cap, 8-figure revenue already, and a Series A imminent, meaning your equity and impact are both outsized
• Work alongside a talent-dense founding team with backgrounds from Citadel Securities, Goldman Sachs, Morgan Stanley, and Silver Lake in a fast-paced, open-communication culture where iteration is fast and the team genuinely likes each other

What you will do:

• Design and build the core shared infrastructure that powers all data generation platforms, human-in-the-loop systems, and evaluation pipelines, taking full ownership of foundational systems for scalability and reliability
• Architect and operate distributed systems in cloud environments (GCP or AWS) using a stack that includes Next.js, React, Node.js, Python, Kubernetes, Kafka, Redis, and Elasticsearch
• Mentor junior engineers, set the technical bar for the infrastructure org, and help define how the company scales its systems from an early-stage team into a category-defining platform

The ideal candidate:

• 4 to 8 years of experience building and maintaining platform infrastructure with full-stack capabilities, ideally from a VC-backed startup, a reputable trading firm, a YC company, or a company that specializes in managing data at scale like Snowflake, Databricks, Confluent, or MongoDB
• Strong track record of building production distributed systems and platform infrastructure, with experience designing and operating systems in cloud environments and a degree from a top 30 school
• A high-ownership IC who thrives in fast-paced, ambiguous environments and is excited about being close to the hardest problems in AI data infrastructure, not looking for a big-tech execution role

Next steps

1. Apply via this LinkedIn job post
2. We’ll review and reach out if there’s a strong match
3. If aligned, we’ll introduce you directly to the team

If this role isn’t the right fit, we may suggest and make introductions to other high-signal startup roles we’re recruiting for – always with your permission.