Founding Engineer - Elo

Praxis, Inc.; San Francisco (CA); On-site; USD 190,000 - 270,000; Full time

Benefits offered by this job

Equity

Competitive compensation

Job summary

Elo, an ad-network for consumer AI apps, seeks a founding engineer to design the ad delivery engine and supporting infrastructure in SF. You will help scale the system as millions of requests per minute rise, shaping how ads are selected and delivered inside AI experiences.

You’ll own critical pieces: the decisioning pipeline, publisher SDK integration, and delivery controls, with high equity and competitive compensation. Join a fast-moving team building contextually relevant ads for AI apps.

Qualifications

• Evidence of writing scalable, low-latency infrastructure.
• Experience with multi-agent or AI-driven workflows.
• Track record shipping high-throughput services.

Responsibilities

• Design the ad decisioning pipeline with latency SLAs.
• Develop the publisher SDK for hours-long integration.
• Build delivery infrastructure for pacing and budget management.
• Maintain observability dashboards for latency percentiles and revenue.

Skills

AI agent harness

Low latency networks

Distributed systems

Compute clusters

Job description

Elo is the ad-network for consumer AI applications. We’ve gone from 0 to XXM users in our publisher network in 45 days of inception.

Background

With AI becoming the primary surface of interaction for internet users, it is inevitable that digital advertising will happen within AI experiences (including but not limited to chat).

Elo is aggregating supply across consumer AI apps to help them monetize their users via ads and help advertisers reach the right audience at the right moment.

We’re backed by top funds like PearVC and Audacious Ventures who’ve invested in billion dollar companies like Doordash and WorkOS. We also have advisors from mobile ad-tech and large consumer AI companies helping us in our mission. Founder is a published researcher and has previously built AI infrastructure at Google.

Progress We’ve already solved the hardest cold start problem with ad networks: onboarding both advertisers and publishers. Now, we need to build and improve the core infrastructure to serve the most contextually relevant ads at the right moment.

Role Founding engineer who’ll help us design the engine for ad delivery inside AI experiences and supporting infrastructure. The role guarantees high equity and competitive compensation

What you’ll build

We’re already processing millions of requests per minute which is set to increase dramatically over the next few months.

You’ll work on:

1. Ad decisioning pipeline: candidate retrieval, scoring, filtering, and final ranking under strict latency SLAs

2. Publisher SDK: lightweight integration that AI app developers embed in hours, not days

3. Delivery infrastructure: pacing, frequency capping, budget management, and campaign throttling

4. Observability stack: real-time dashboards for auction win rates, fill rates, revenue, and latency percentiles
   

What we’re looking for

We look for evidence of technical excellence.

If you’ve built any of the following, we’d love to chat:

1. Your own AI agent harness or multi-agent workflow for complex tasks

2. Low latency network infrastructure and data pipelines serving millions of requests per second

3. Scalable and self-healing infrastructure with 1000s of compute workers spinning up and down with variable demand

4. High frequency trading systems

Or anything that you believe reflects high calibre of engineering design and low-level systems understanding.

You’re a good fit if you:

1. Care about your craft and operate ethically

2. Take extreme ownership of outcomes

3. Like to operate independently

4. Ship extremely fast and effectively use AI to accelerate your impact

5. Want to operate in a fun and social work environment