About AfterQuery

AfterQuery is an applied research lab curating data solutions for foundation model development.

We serve every frontier AI lab with the mission of delivering the best data to power the best models. In doing so, we can make expertise that once took a lifetime to build available to anyone who needs it. Our customers are the ones building the foundation models themselves and our work sits directly in the loop of how those systems improve.

This is a rare opportunity to join a company at a defining moment in AI. Since raising our $30M Series A at a $300M valuation, AfterQuery has grown well over a $100M revenue run rate.

We're based in San Francisco and backed by leading investors including Altos Ventures, BoxGroup, and Y Combinator and angels from Google DeepMind, OpenAI, Anthropic, Meta Superintelligence Labs, and Microsoft AI.

Why Apply

Massive Opportunity:
We were one of the fastest-growing YC companies in our batch, and we believe we can become one of the fastest-growing YC companies of all time.

Founding Impact:
You will own and architect core infrastructure systems that power our platform from the ground up.

Equity & Growth:
Competitive salary and meaningful equity. As we scale, you’ll have the opportunity to shape the engineering organization and lead major technical initiatives.

Strong Team:
Our founding team has experience from Citadel Securities, Meta, Google, Silver Lake, and Morgan Stanley — work alongside world-class engineers and researchers.

Overview

As one of our Latin American engineers, you’ll be critical in creating data infrastructure that will be shaping the future development of frontier models. You will get a lot of responsibility, owning entire projects end-to-end – meaning you can see your impact instantly.

Responsibilities

Design and build scalable systems, focusing on our AfterQuery Experts site

Collaborate across research, product, and design to ship features quickly without sacrificing quality

Write clean, maintainable code and contribute to documentation

Participate in code reviews and design discussions

Solve real-world scalability and reliability challenges

Contribute to the core infrastructure powering data and evaluation for the world's leading AI labs

Required Qualifications

Ideally 5+ years of experience

Strong coding fundamentals in Node.js and TypeScript, Python, and/or Go

Deep understanding of distributed systems, scalability challenges, and system design

Familiarity with cloud platforms such as GCP or AWS, Kubernetes, APIs, and NoSQL databases

Ability to reason about trade-offs and balance speed versus reliability under pressure

Active GitHub with real projects demonstrating you are a builder at heart

Works autonomously and collaboratively without burning out under heavy load

Proactive, identifies problems and drives solutions without being told to

High-output and high-accountability mindset, can work banker hours when needed

Strong bias toward delivering simple solutions to complex problems

Strong written and verbal communication skills

Can clearly and compellingly articulate why they want to join a startup and work in AI now

Preferred Qualifications

Background as a founding engineer at a high-growth startup

Ex-founder of a technically sophisticated and complex product

Has trialed or succeeded in past fast-paced startup roles with strong references