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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Software Engineer - **Company:** APOSTLE INC - **Location:** United States (Remote available) - **Experience:** Expert - **Salary:** $160,000 - $215,000 - **Contract:** Permanent contract - **Skills:** Computer-Aided Design, Application Programming Interfaces (APIs), Artificial Intelligence, Amazon Web Services, User Authentication, BigQuery, Cloud Storage, Software Debugging, Programming Tools, Distributed Systems, PostgreSQL, Node.Js, Redis, Software Engineering, TypeScript, Management of Software Versions, ReactJS, AI Coding Agents, Backend, Agentic-AI, Event Driven Architecture, Build Management, Production Code, Build Tools, Front End Software Development, Virtual Agents, Api Design, Restful APIs, Agent2Agent Protocol - **Published:** November 13, 2026 - **Apply:** https://www.builtincolorado.com/auth/login?destination=/job/senior-software-engineer/12209129 ## About the Role * 5+ years of professional software product engineering experience, ideally building distributed backend systems or complex production applications. Exceptional candidates with 4+ years of experience are encouraged to apply. * AI-native engineering mindset: 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. 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., * Backend & APIs: TypeScript/Node.js, REST and event-driven services * Frontend: React * Agent Interfaces: MCP servers and A2A protocol handlers * Data: PostgreSQL, BigQuery, Cloud Storage, Redis * Infrastructure: GCP, AWS We're interested in engineers who understand systems, think critically about technical problems, and know how to leverage AI to build effectively. Deep familiarity with every technology in our stack is less important than strong engineering fundamentals, adaptability, and the ability to learn quickly. Leveling & Growth We're hiring at the Senior Software Engineer level, with flexibility to consider candidates whose experience and technical capabilities warrant a broader scope of responsibility. At Apostra, we value demonstrated impact, ownership, and technical ability over titles alone. For an exceptional candidate, there may be an opportunity to grow into Staff-level responsibilities, taking on greater technical ownership and influence as the company and engineering organization evolve. We're most interested in what you can build, how you approach difficult problems, and how you contribute to the success of a small, highly collaborative engineering team. ## Description Build scalable APIs, agent interfaces, MCP servers, A2A communication layers, and high-throughput advertising transaction systems. Design distributed services, authentication, protocols, and transaction flows while integrating emerging AI agent frameworks. This hands-on, backend-leaning full-stack role requires ownership of complex technical challenges, rapid experimentation, and effective use of AI coding tools. The engineer will collaborate closely with a small team and contribute to architectural decisions and engineering workflow improvements. The summary above was generated by AI About Apostra Apostra is defining a new future for advertising, for both humans and their agents. Our founders helped build the technology that shaped advertising as we know it today. Now, we're reimagining it from the ground up for a world of people and agents, with human intent at its heart. We're creating a place where advertisers, media owners and their agents can discover and act on every kind of media, opening up opportunities that have historically been fragmented and hard to access. About the Role Our technical team is creating the infrastructure that enables AI agents to discover, negotiate, and transact media inventory autonomously. As a Senior Software Engineer, you'll be a hands-on contributor to the APIs, protocols, and agent interfaces that power our agentic advertising platform. You'll help build systems where AI agents are first-class participants, with their own authentication, capabilities, and communication standards. You'll work at the intersection of advertising technology, distributed systems, and emerging AI agent frameworks, tackling complex technical challenges and helping shape how our marketplace evolves. This is a full-stack (80/20 backend-leaning), hands-on product engineering role. You'll design and build production systems, explore new agent communication patterns, and take meaningful ownership of technical problems from concept through implementation. We're looking for someone who combines strong engineering fundamentals with curiosity, resourcefulness, and an eagerness to work with emerging AI technologies. This Isn't a Typical Engineering Role * AI isn't an add-on to how we engineer; it's central to how we build. We embrace AI-first development workflows and expect engineers to actively leverage AI coding agents and tools throughout their work. We're looking for people who are genuinely excited about this shift, experiment with emerging capabilities, and continuously rethink what's possible when AI becomes an integral part of the engineering process. * We're operating in a space without a fixed playbook. We value engineers who are comfortable navigating ambiguity, figuring things out, and creating structure where none exists. * Our approach favors rapid experimentation over upfront perfection. We test, learn, iterate, and formalize what works. * We move quickly, tackle difficult problems, and expect engineers to take ownership of their work. You'll have significant autonomy and the opportunity to make a meaningful impact. * We're a small, collaborative team where initiative matters. We value people who know how to make progress independently, communicate proactively, and seek out the context or support they need to succeed. 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.