Software Engineer, API Frontiers

Jobtailor; California (MO); On-site; USD 140,000 - 210,000; Full time

Job summary

Jobtailor seeks a seasoned backend/API engineer to design, build, and operate scalable APIs and services that enable frontier model capabilities for developers. You will collaborate across Research, Safety, Codex, and API teams to define API behavior and staged launches.

You will own performance, observability, and reliability, tackling concurrency, streaming, and long-running workflows, while turning feedback into durable product improvements.

Qualifications

• 5+ years of experience building and operating backend services or developer-facing APIs in production.
• Strong software engineering fundamentals.
• Practical knowledge of distributed systems, concurrency, and asynchronous execution.
• Ability to diagnose production failures and performance bottlenecks using observability data and profiling.
• Product judgment and developer empathy.
• Track record of translating complex capabilities into clear, dependable APIs.
• Experience taking ownership of ambiguous technical problems from defining an approach through shipping and improving the result.
• Clear communication and effective collaboration across engineering, research, product, and safety disciplines.
• Experience with Rust, streaming protocols or WebSockets, or long-running workflow systems is a plus.

Responsibilities

• Design, build, and operate APIs and backend services that bring frontier model capabilities to developers
• Partner with Research, Safety, Codex, and API teams to define API behavior and deliver safe, staged launches
• Build API capabilities for agent workflows, including task delegation, context sharing, and parallel execution
• Strengthen long-running request reliability across timeouts, cancellation, streaming, and background execution
• Improve request-processing performance and tail latency through profiling, efficient systems code, and persistent connections
• Turn developer feedback and production failures into better observability, diagnostics, and lasting product improvements

Skills

API Design

Backend Development

Concurrency

Asynchronous Execution

Performance Profiling

Observability

Clear Communication

Developer Empathy

Product Judgment

Effective Collaboration

Context Sharing

Long-Running Workflows

Tools

Rust

Streaming Protocols

WebSockets

Job description

• Design, build, and operate APIs and backend services that bring frontier model capabilities to developers
• Partner with Research, Safety, Codex, and API teams to define API behavior and deliver safe, staged launches
• Build API capabilities for agent workflows, including task delegation, context sharing, and parallel execution
• Strengthen long-running request reliability across timeouts, cancellation, streaming, and background execution
• Improve request-processing performance and tail latency through profiling, efficient systems code, and persistent connections
• Turn developer feedback and production failures into better observability, diagnostics, and lasting product improvements

Requirements

• 5+ years of experience building and operating backend services or developer-facing APIs in production
• Strong software engineering fundamentals
• Practical knowledge of distributed systems, concurrency, and asynchronous execution
• Ability to diagnose production failures and performance bottlenecks using observability data and profiling
• Product judgment and developer empathy
• Track record of translating complex capabilities into clear, dependable APIs
• Experience taking ownership of ambiguous technical problems from defining an approach through shipping and improving the result
• Clear communication and effective collaboration across engineering, research, product, and safety disciplines
• Experience with Rust, streaming protocols or WebSockets, or long-running workflow systems is a plus

Core Competencies

Demonstrates expertise in designing and operating APIs and backend services, with a strong focus on performance optimization, observability, and developer collaboration. Proven ability to translate complex functionalities into reliable APIs while effectively diagnosing and resolving production issues.

Highest-signal resume keywords

• API Development
• Backend Services
• Distributed Systems
• Performance Optimization
• Clear Communication

Hard Skills

• API Design
• Backend Development
• Concurrency
• Asynchronous Execution
• Performance Profiling
• Observability
• Rust
• Streaming Protocols
• WebSockets
• Task Delegation

Soft Skills

• Developer Empathy
• Product Judgment
• Effective Collaboration

Industry Keywords

• Production Failures
• Request Processing
• Long-Running Workflows
• Context Sharing
• Background Execution