Founding Engineer (150,000 250,000 + Equity) at Series A AI infrastructure startup

San Francisco, CA - USA

Monthly Salary: $ 150000 - 250000

Posted on: 2 days ago

Vacancies: 1 Vacancy

Department:

Marketing

Job Summary

This is a job that Jill our AI Recruiter is recruiting for on behalf of one of our customers.
She will pick the best candidates from Jacks network

The next step is to speak to Jack.

Founding Engineer (Full Stack ML DevTools & Systems)

Salary: $150000 - $250000 Equity

Company Description: Series A AI infrastructure startup

Job Description:
Join an elite team building the foundational platform for LLM alignment and reinforcement learning. You will own the development of core infrastructure Python SDKs and developer workflows that enable foundation labs and enterprise teams to train and evaluate AI models at scale. This is a high-ownership role bridging full-stack systems with cutting-edge machine learning.

Location: San Francisco USA

Why this role is remarkable:

Founding member opportunity at a high-talent density startup founded by experienced researchers and engineers.
Backed by top-tier VCs at the Series A stage building critical infrastructure for the future of post-training data.
Direct impact on how the worlds leading foundation labs and Fortune 500s train and align their LLMs.

What you will do:

Design and implement backend systems for reinforcement fine-tuning (RFT) jobs and data flow primitives.
Build and iterate on a high-quality Python SDK focusing on ergonomics reliability and elite developer experience.
Partner directly with customers at frontier labs to translate real-world feedback into scalable product abstractions.

The ideal candidate:

Elite Python engineer with a strong background in distributed systems Docker and cloud-native infrastructure.
Product-minded builder with a deep interest in ML fundamentals reinforcement learning and evaluation frameworks.
Experience designing developer-facing tools such as SDKs CLIs or complex API surfaces with high technical aptitude.

Who are Jack & Jill

Ok Ill go first. Im Jack an AI that gets to know you on a quick call learning what youre great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up supporting you with applications interview prep and moral support.

And Im Jill an AI Recruiter who talks to companies to understand who theyre looking to hire. Then I recruit from Jacks network making an introduction when I spot an excellent candidate.

Next steps

Step 1. Visit our website.
Step 2. Click Talk to Jack.
Step 3. Talk to Jack so he can understand your experience and ambitions.
Step 4. Jack will make sure Jill (the AI agent working for the company) considers you for this role.
Step 5. If Jill thinks youre a great fit and her client wants to meet you they will make the introduction.
Step 6. If not Jack will find you excellent alternatives. All for free.

We never post fake jobs

This isnt a trick. This is an open role that Jill is currently recruiting for from Jacks network.
Sometimes Jills clients ask her to anonymize their jobs when she advertises them which means she cant share all the details in the job description.
We appreciate this can make them look a bit suspect but there isnt much we can do about it.

Give Jack a spin! You could land this role. If not most people find him incredibly helpful with their job search and were giving his services away for free.

Required Experience:

This is a job that Jill our AI Recruiter is recruiting for on behalf of one of our customers.She will pick the best candidates from Jacks networkThe next step is to speak to Jack.Founding Engineer (Full Stack ML DevTools & Systems)Salary: $150000 - $250000 EquityCompany Description: Series A AI inf...