Staff Software Engineer (Fullstack, BE-leaning)

Job summary

Design and build scalable APIs, agent interfaces, MCP servers, and A2A communication layers for an AI-powered programmatic advertising marketplace. Lead architectural decisions and production development, collaborate with advertising and platform partners, and mentor engineers on APIs, distributed systems, and agent architectures.

Job details

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 We’re building the future of programmatic advertising through AI agents. Our technical team is creating the infrastructure that enables AI agents to discover, negotiate, and transact media inventory autonomously. In this role, you’ll be a technical leader responsible for the APIs, protocols, and agent interfaces that power our agentic advertising platform. You’ll design 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—making architectural decisions that shape how our marketplace evolves. This is a Fullstack (80/20 backend leaning), hands-on leadership role. You’ll write production code, prototype new agent communication patterns, review system designs, and mentor engineers while setting technical direction. This isn’t a typical engineering role We’re operating in a space without a fixed playbook, so this role is best suited for builders who are comfortable creating structure where none exists. Our approach favors rapid experimentation over upfront perfection—we test, learn, and then formalize what works. The pace is fast and often pushes beyond what feels comfortable. For the right person, that’s part of the appeal. We’re also looking for engineers who are already actively exploring AI—this isn’t a “learn it on the job” environment. Responsibilities Design and architect scalable APIs for both human and AI agent clients Lead development of agent interfaces, MCP servers, and A2A communication layers Build and operate high-throughput systems for real-time advertising transactions Evaluate and integrate emerging agent frameworks and protocols Partner with product and design to define clear, agent-friendly API contracts Drive architectural decisions around authentication, protocols, and transaction flows Collaborate with external DSPs, SSPs, and agent platform partners Mentor engineers on API design, distributed systems, and agent architectures Anticipate and address edge cases in autonomous agent behavior Qualifications 8+ years building distributed backend systems at scale 4+ years in a technical leadership role 4+ years working professionally within the AdTech ecosystem Strong expertise in API design and architecture (REST, event-driven systems, auth, versioning) Experience with AI agent frameworks and communication protocols, or the ability to rapidly learn and evaluate them Proficiency with TypeScript/Node.js, React, and cloud platforms (GCP or AWS) Experience designing systems for autonomous or semi-autonomous decision-making Track record of mentoring engineers and fostering a collaborative team culture Comfort working in fast-moving, evolving environments Tech Stack API Layer: TypeScript/Node.js, REST and event-driven services Agent Interfaces: MCP servers and A2A protocol handlers Data: PostgreSQL, BigQuery, Cloud Storage, Redis As the agent ecosystem evolves, you’ll help evaluate new technologies and ensure our marketplace remains at the forefront. Compensation The salary range for this role is $180k-$230k USD / $190k-$245k CAD. These ranges span multiple location-based salary bands across the US and Canada. Candidates are aligned to a narrower range based on geographic market compensation data specific to where they live, and final offers reflect demonstrated skills, experience, and role expectations. Benefits & Perks Details vary by location (USA/Canada), but all employees receive: Health & wellness: Comprehensive medical, dental, and vision coverage with significant employer contribution; short- and long-term disability coverage; health savings/flexible spending options Retirement: Employer-matched retirement savings plan (401(k) or RRSP) Time off: Generous paid time off, statutory holidays, and year-end office closure Parental leave: 13 weeks fully paid (eligibility requirements apply) Remote work: Company-provided home office equipment, setup stipend, and access to WeWork spaces Equity: Stock options A Note To Applicants We believe that all people are capable of great things. We encourage you to apply even if you do not meet all of the requirements that are listed within this job description.

What you’ll do

Design and build scalable APIs, agent interfaces, MCP servers, and A2A communication layers for an AI-powered programmatic advertising marketplace. Lead architectural decisions and production development, collaborate with advertising and platform partners, and mentor engineers on APIs, distributed systems, and agent architectures.

Requirements

Requires 8+ years building distributed backend systems at scale, 4+ years in technical leadership, and 4+ years of professional AdTech experience. Candidates should bring strong API architecture expertise, experience with AI agent frameworks or the ability to evaluate them quickly, proficiency in TypeScript/Node.js, React, and GCP or AWS, and a record of mentoring engineers.

Benefits

• Medical Insurance
• Dental Insurance
• Vision Insurance
• Disability Coverage
• Health Savings Account
• Flexible Spending Account
• Employer-Matched Retirement Plan
• Paid Time Off
• Statutory Holidays
• Year-End Office Closure
• Paid Parental Leave
• Home Office Equipment
• Home Office Setup Stipend
• WeWork Access
• Stock Options

Listed skills

• Node.js · Preferred
• REST APIs · Preferred
• PostgreSQL · Preferred
• React · Preferred
• TypeScript · Preferred

Other relevant skills

Identified from the job description. Confirm important requirements above.

• Distributed Systems
• Technical Leadership
• API Design
• TypeScript
• Node.js
• React
• REST
• Event-Driven Systems
• Authentication
• AI Agent Frameworks
• MCP Servers
• A2A Protocol
• AdTech
• Cloud Platforms
• PostgreSQL
• BigQuery

Job areas

• Software
• Technology
• Management & Leadership
• Engineering