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Founding Engineer, Optimization

Pax Historia

On-site
San Francisco, CA
Full-time
Staff
Principal
$140k–$220kPosted 59m ago

Real job — pulled straight from Pax Historia’s careers page · Verified September 7, 2026 · No reposts.

Job description

Pax Historia is hiring a Founding Engineer, Optimization — a full-time, based in San Francisco, CA role ($140k–$220k). Apply directly on Pax Historia's careers page below.

Founding Engineer - Harness Optimization

Department: Engineering

Location: San Francisco

Compensation: $140K – $220K • Offers Equity

Employment Type: FullTime

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

Each game on Pax Historia is run by the AI model the user picked to run their game. Games are much more fun if the AI running their game is able to balance long-term internal consistency with creative developments - in short, if the AI is good at storytelling.

But today, we’ve barely scratched the surface of getting the best possible results out of the ~240B tokens processed on our site each week. The same default AI workflows run across very different models, and we haven’t done much to adapt to the quirks of the 37+ models on our site now. We think our games can be much more interesting than they are today, which is why we’re hiring for this role.

On day one, you’d experiment with workflow architecture and prompts to begin making improvements and building the evals needed to figure out whether you’re actually making games better.

You might be a great fit if you’re extremely experiment-driven, a big-picture systems-thinker, and a storyteller yourself. 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.

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Frequently asked questions

What is the salary for Founding Engineer, Optimization at Pax Historia?

The estimated salary range for Founding Engineer, Optimization at Pax Historia is $140,000 - $220,000 USD per year.

What skills are required for Founding Engineer, Optimization at Pax Historia?

The required skills for Founding Engineer, Optimization at Pax Historia include: AI, Machine Learning.

What is the seniority level for Founding Engineer, Optimization at Pax Historia?

Founding Engineer, Optimization at Pax Historia is a Staff / Principal level position.

How do I apply for Founding Engineer, Optimization at Pax Historia?

You can view the full description and apply for Founding Engineer, Optimization at Pax Historia on EchoJobs: https://echojobs.io/job/pax-historia-founding-engineer-harness-optimization-tdaqm.