Founding Engineer - LLM Infra & Platform

Location: San Francisco

Job Type: Full-time

Salary: $140K - $220K

Experience: Any (new grads ok)

Visa: US citizen/visa only

Company

Pax Historia is creating the future of interactive entertainment.

We’re building the platform for worldbuilders, storytellers, and game devs to create and publish any ‘what if’ they can think of. So far, most of the 25k+ user published presets on our site are historical (eg, ‘what if Rome never fell?’), but fantasy and sci fi are the fastest growing categories on the site.

We have seen over 92 million rounds played and raised a 10M+ seed round in March. We’re backed by Y Combinator (W26), Bessemer, Pace Capital, Z Fellows, and more.

Role

Every game on Pax Historia depends on our ability to send huge numbers of requests across many AI providers and get the right response back quickly, reliably, and cheaply.

We’re hiring an engineer to own that system. You’ll work on provider reliability, structured outputs, caching, routing, and monitoring. At the end of the day, you will need to:

  • Ensure that the 37+ models on our site reliably handle our ~240 billion weekly tokens.

  • Reduce costs and latency for our 60k+ daily active users wherever possible.

You will not be in charge of model-training. We do not run model inference ourselves.

If you’re obsessed with detail, data oriented, and have a strong tendency to verify everything, then this might be a great fit for you. We don’t expect you to have done this exact job before, but we are expecting you to be a fast learner with extremely strong fundamentals.

Logistics

You’ll be our 7th team member. We work in-person in San Francisco, 5+ days/week. We are open to sponsoring visas.

Comp will include meaningful equity to reflect your responsibility as a founding engineer.

Summary

Own reliability, structured outputs, caching, routing, and monitoring for 37+ models serving ~240 billion weekly tokens to 60k+ daily active users, reducing cost and latency. Open to new grads with strong fundamentals, attention to detail, and fast learning.

Responsibilities

Ensure 37+ models reliably handle ~240 billion weekly tokens; reduce costs and latency for 60k+ daily active users; own provider reliability, structured outputs, caching, routing, and monitoring

Qualifications

Any (new grads ok)

Experience requirements

Any (new grads ok)

Benefits

Meaningful equity