How to apply for Founding Software Engineer

About Thirdlaw

Thirdlaw builds the control layer for AI in the enterprise. It helps IT and security teams monitor, evaluate, and control AI behavior at runtime, answering the question 'Is this OK?' and taking action when it is not. The company is backed by top-tier venture firms and works with enterprise design partners.

About the role

As a founding software engineer, you will architect core backend systems for event ingestion, real-time risk evaluation, semantic search, and investigation-grade querying. You will design streaming data pipelines that reconcile latency, correctness, and observability. This role is foundational: you will shape the nervous system for a new class of software where AI agents reason, act, and fail unpredictably.

A typical day

You will spend time designing and coding backend services for event ingestion and real-time risk evaluation. You may work on optimizing streaming pipelines, improving semantic search, or building investigation-grade querying tools. You will collaborate with a small team to ensure the system reliably monitors and controls AI behavior at runtime.

Who Thirdlaw is looking for

• Experience building and operating distributed backend systems, especially event ingestion and streaming data pipelines.
• Comfort with real-time processing and balancing latency, correctness, and observability trade-offs.
• Familiarity with semantic search, query systems, or investigation-grade data retrieval.
• Interest in AI safety, compliance, and operational risks in enterprise environments.

Tips for this application

• Highlight specific projects where you designed event ingestion or streaming pipelines, including scale and latency numbers.
• Mention any experience with real-time risk evaluation, anomaly detection, or observability systems.
• Show familiarity with semantic search or querying large datasets for investigations.
• Explain why you want to work on AI control and safety at runtime, not just model training or logging.
• Reference Thirdlaw's focus on answering 'Is this OK?' and taking real-time action in your application.

What to cover in your cover letter

['Your hands-on experience architecting backend systems for streaming data and real-time evaluation.', 'How you have balanced latency, correctness, and observability in distributed pipelines.', 'Your motivation to build infrastructure that monitors and controls AI behavior in production.', 'Any work you have done with semantic search, investigation-grade querying, or enterprise security/compliance tooling.']

Research before applying

• Read Thirdlaw's website and any public materials to understand their product for monitoring and controlling AI behavior.
• Look into common AI safety and compliance risks in enterprises, such as data leaks or unpredictable model decisions.
• Research existing observability tools and why they fall short for AI runtime control.
• Check if Thirdlaw has published engineering blogs, talks, or documentation about their architecture.

Likely interview topics

Based on the job description, expect questions about:

• Designing a streaming data pipeline for real-time risk evaluation with low latency.
• Trade-offs between correctness and observability in distributed systems.
• How to implement semantic search or investigation-grade querying over large event datasets.
• Approaches to monitoring and controlling AI agent behavior at runtime.
• Your experience with event ingestion systems and handling high-throughput data.

Common mistakes to avoid

• Focusing only on model training or tuning without addressing backend systems and infrastructure.
• Ignoring the real-time and runtime aspects of the role; treating it as a batch processing job.
• Using generic language about AI safety without connecting it to concrete engineering challenges like event ingestion or semantic search.