Software Engineer, Core Services

One Signal is the autonomous lifecycle marketing engine for B2C app companies. Marketers can orchestrate the campaigns that onboard, engage, and retain users, increasing LTV and reducing churn. Companies like Zynga, , and Philips use One Signal to drive outcomes with AI that scales with you.

We’re Series C, venture-backed by Signal Fire, Rakuten Ventures, Y Combinator, Hub Spot, and BAM Elevate. We offer remote work as the default option in the United States in California, Colorado, Florida, Massachusetts, New York, New Jersey, Ohio, Oregon, Pennsylvania, Texas, Utah and Washington. As well as in the UK, Singapore, and Canada - with plans to expand the locations we support in the future.

Some roles are hybrid roles and will be listed as such. We have offices in San Francisco and San Mateo in CA, in London, UK, and offer flex seating options for employees to work together in‑person in NY and other areas. Hiring in Singapore is done in partnership with a local EOR, and hiring in Canada is done in partnership with Rippling's EOR.

One Signal has a lot of the great tech startup qualities you'd expect, but we don't stop there. Our massive scale and small team, emphasis on collaboration, and focus on ownership and personal growth make One Signal a uniquely great place to work.

One Signal powers billions of messages and HTTP requests every day. We’ve achieved this scale by pairing modern, high‑performance data stores with efficient technologies such as Rust, creating reliable systems that maximize performance and resource utilization.

The Core Services team builds and operates the foundational services behind One Signal’s platform, including our delivery pipeline, gRPC services, Kafka infrastructure, and other systems processing hundreds of thousands of events per second. You’ll work with technologies including Rust, gRPC, Redis, Kafka, Scylla, Click House, Pulsar, PostgreSQL, and occasionally Golang and Ruby.

As One Signal evolves into a fully autonomous platform, the Core Services team will build and scale the high‑stakes services that our products and engineering teams rely on. As a Staff Software Engineer, you’ll lead significant projects and directly shape the reliability, performance, and future of our platform.

• Collaborate with engineers to architect and implement high‑performance services that are durable and reliable
• Participate in code reviews, design reviews, and production on‑call rotation
• Work together with the team to resolve production issues and ensure system scalability
• Conduct data analysis, performance monitoring, and system optimization through benchmarking/profiling.
• Work independently to drive experiments and solutions for business needs
• Design synchronous and asynchronous APIs for communicating between services in a large distributed system
• Design schemas for relational and non‑relational databases

• 8+ years of experience working as a software engineer
• Experience operating reliable production systems at scale
• Experience writing high‑performance code in a compiled language such as Rust, C/C++, or Golang
• Ability to reason about how data flows through distributed systems
• Experience using LLM‑powered coding tools, such as Claude, to accelerate development, improve code quality, and enhance engineering workflows.
• Bias towards automating the boring stuff

We value a variety of experiences, and these are not required. It would be a added bonus if you have experience in any of the following:

• Experience with any of Redis, Kafka, Postgres, Click House, gRPC
• Experience profiling applications to improve performance in terms of time/CPU/memory
• Experience debugging issues in distributed systems

• Friendliness & Empathy
• Accountability…