The Role

We are looking for a Backend Engineer to own the systems that ingest, evaluate, and serve agent behavior data at production scale. You will work across telemetry ingestion, platform reliability, sandbox infrastructure, and the API surface that customers and integrations build on. Some weeks you will be deep in distributed systems and query performance. Other weeks you will ship a customer-facing feature across backend, APIs, and the data layer.
What you'll do:

• Own platform scaling, reliability, and latency: caching, retries, and backpressure as customer traffic grows
• Optimize sandbox environments for speed, isolation, and cost efficiency
• Build high-throughput telemetry ingestion and tune OLAP performance: partitioning, indexing, and query optimization over billions of spans
• Own the API surface used by the NeoSigma platform UI, SDKs, MCP server, and customer integrations
• Build evaluation pipelines with retry semantics, failure recovery, and tenant-level scheduling
• Work directly with customers to debug agent failures and turn those signals into infrastructure improvements
• Roll out safely with feature flags, design docs, and production observability

What we look for:

• Strong backend engineering experience building and operating production systems under real load
• Solid fundamentals in distributed systems, API design, data modelling, and performance
• Experience with high-volume telemetry, trace, or event data at scale
• Strong intuition for data systems: query patterns, indexing, partitioning, and latency
• High ownership mentality: you debug production issues and don't wait for someone else to notice what's broken
• Clear communicator across design docs, code reviews, and tradeoff discussions
• Bachelor’s degree in Computer Science, Engineering, or related field (or equivalent practical experience)

Our Core Values:

• Customer Obsession - We start with the customer and work backwards. We aim to earn trust through consistent delivery, thoughtful listening, and by obsessing over customers.
• Intellectual Honesty - We operate with high trust and low ego. Ideas matter more than titles, and we communicate openly and directly while assuming good intent, even in strong disagreement.
• Bias for Action - We set high standards and move quickly to meet them. We prefer building and learning with customers over debating in the abstract, and we iterate based on real feedback.
• Extreme Ownership - We take responsibility for outcomes, not just tasks. Ownership means seeing problems through to completion and ensuring solutions truly work in practice.

Benefits and perks

• Competitive salary plus meaningful equity package
• Comprehensive medical benefits and generous PTO
• Flexible work arrangements
• Direct impact on company direction and technical decisions
• High ownership and the opportunity to make a career-defining impact

• Visa sponsorship

As a founding member, you’ll help define the technical foundation of NeoSigma. Your scope will grow with the company, from owning core systems end-to-end to shaping architecture, hiring, and engineering culture. This role has a natural path toward technical leadership or engineering management as the team scales.

About Us

NeoSigma is a product-driven research lab building the intelligence layer that helps close the feedback loop between your customers, products, and AI systems.

We are a small, intensely technical team of researchers and engineers who have trained frontier-scale models and widely used AI products and agents at Parallel Web, Essential AI, MIT, Apple, and Amazon.

We are backed by world-class investors and leaders from Google DeepMind, OpenAI, Decagon and others.