Senior Software Engineer

Apostra is building infrastructure for AI agents to discover, negotiate, and transact advertising media inventory. The Senior Software Engineer will build APIs, protocols, and agent interfaces for its advertising platform, while developing and operating production systems and contributing to architectural decisions.

Responsibilities:

• Design and build scalable APIs for both human and AI agent clients
• Develop agent interfaces, MCP servers, and A2A communication layers
• Build and operate high-throughput systems for real-time advertising transactions
• Explore, evaluate, and integrate emerging agent frameworks and protocols
• Contribute to architectural decisions around authentication, protocols, and transaction flows
• Take ownership of complex technical challenges, anticipating edge cases in autonomous agent behavior
• Continuously improve engineering workflows, including the practical application of AI tools to accelerate development and problem-solving
• Collaborate with teammates to share knowledge, work through technical challenges, and raise the overall quality of our engineering output

Requirements:

• 5+ years of professional software product engineering experience
• Exceptional candidates with 4+ years of experience are encouraged to apply
• Demonstrated experience incorporating AI coding agents and tools into your development workflow
• You actively experiment with AI-assisted development and are excited about the evolving role of AI in software engineering
• Strong engineering fundamentals, with the ability to think through complex technical problems and translate them into practical, scalable solutions
• Experience designing and building APIs and backend services (REST, event-driven systems, authentication, versioning)
• Experience working with distributed systems, high-throughput applications, or systems involving autonomous or semi-autonomous decision-making
• A self-starter mentality and the ability to take ownership of projects and drive them forward with minimal direction
• Comfortable navigating ambiguity, learning unfamiliar technologies, and adapting quickly as priorities and requirements evolve
• Strong communication skills and the confidence to advocate for what you need, ask questions, and collaborate effectively with teammates
• A low-ego approach to engineering: open to feedback, willing to challenge your own assumptions, and more interested in finding the right solution than being right
• this position is limited to candidates authorized to work in the United States or Canada
• We are unable to provide employer-sponsored work authorization now or in the future
• Backgrounds in early-stage startups, founding engineering teams, or forward-deployed engineering can be particularly valuable, especially where you've had to operate independently, take ownership across multiple areas, and work directly with customers or external partners