Software Engineer - Data / ML

Who We Are

Koah Labs is building the ad network to power the next generation of AI-native products. Our mission is to help publishers monetize and help advertisers reach the right audience — without compromising speed, UX, or privacy.

We’re a small, tight-knit team in San Francisco with backgrounds at X, Apple, Meta and early-stage startups. We’ve raised $5.7M from top investors and are growing fast with real traction on both the publisher and advertiser sides of the marketplace.

Working at Koah means joining at the ground floor: you’ll ship code that shapes the company and the ecosystem we’re building. We move quickly, operate with high trust, and care deeply about craft.

Our Stack

• Infra: Terraform, AWS, LGTM (Loki, Grafana, Tempo, Mimir), Tailscale, Cloudflare

• Data: PostgreSQL, ClickHouse, Redis, Kafka, Python

• Core Application: Ruby on Rails, React, TypeScript

• SDKs: Flutter, React Native, Android, iOS

Example projects

• Build data pipelines using Debezium to stream real-time changes from PostgreSQL to our OLAP database for analytics workloads

• Reduce p99 latency in critical write paths by optimizing SQL query execution plans, implementing robust retry mechanisms, and enforcing strict timeouts for third-party services

• Tune conversion and clickthrough rate metrics in our core ad matcher from analyzing impression and click data

• Enhance ad matching algorithms using regression analysis to identify data patterns and develop hypotheses for new predictive features that improve conversion likelihood

• Set up experiment tracking and observability with logs and custom metrics that make it easy for us to understand why certain ads are chosen

You might be a fit if

• You like debugging and optimizing performance

• You are detail oriented and use data to support your claims

• You enjoy digging deeply and owning the platform side supporting product

• You enjoy experimentation, measuring, and creating reliable systems