RUNTIME LABS

8:23:55 PM
Tuesday, February 24, 2026
UTC

Software Engineer, Security

Runtime Labs develops a secure and time-aware platform that aligns language models with users, building Runtime as a personal memory layer where conversations and events are privately anchored across time.

This is a founding role shaping the core security and infrastructure architecture of the product.

About the Role

  • Design and implement zero-knowledge, client-side encrypted systems.
  • Build cryptographic primitives and infrastructure that enable user-controlled context, encrypted retrieval, and secure multi-device sync.
  • Harden backend systems and storage layers to support scale and reliability.
  • Drive security engineering across the stack: key hierarchy, metadata minimization, encrypted sync, secure deletion, and LM access controls.
  • Collaborate with the founder to extend the Runtime Temporal API and the foundations of a time-anchored memory system for intelligent planning.
  • Build tools that strengthen security, reliability, and engineering velocity, with strong documentation and architectural clarity.

About the Person

  • A security-minded engineer with strong fundamentals in cryptography, distributed systems, or secure application architecture—deeply motivated by building private-by-default systems.
  • Comfortable designing foundational systems: key derivation, encrypted metadata structures, event-driven backends, secure sync protocols, and multi-device flows.
  • Values clean architecture and crisp written communication; works well in a small, fast-moving team.
  • Research-driven: you stay current with local-first software, distributed systems, and privacy-preserving AI.
  • Motivated by long-term impact and cross-stack contributions—from secure client code to backend infrastructure— and committed to building systems users can trust with sensitive data.