Senior Software Engineer, AI — Ecosystem

Brex • Seattle, WA

2h • $192,000 - $240,000 • Hybrid

About The Position

Brex is the AI-powered spend platform. We help companies spend with confidence with integrated corporate cards, banking, and global payments, plus intuitive software for travel and expenses. Tens of thousands of companies from startups to enterprises — including DoorDash, Flexport, and Compass — use Brex to proactively control spend, reduce costs, and increase efficiency on a global scale.
Working at Brex allows you to push your limits, challenge the status quo, and collaborate with some of the brightest minds in the industry. We’re committed to building a diverse team and inclusive culture and believe your potential should only be limited by how big you can dream. We make this a reality by empowering you with the tools, resources, and support you need to grow your career.
AI Engineering at Brex is redefining how businesses run their finances by building intelligent, autonomous systems directly into the Brex platform. Our teams develop AI agents that don’t just surface insights—they take action, optimizing spend, managing workflows, and making real-time decisions on behalf of our customers. By deeply integrating proprietary financial data with product and platform infrastructure, we’re turning complex financial operations into simple, automated experiences and setting a new standard for how modern finance works.
You’ll be the senior technical owner for Brex’s external AI ecosystem: the integrations, surfaces, and standards that allow customers to interact with Brex through third-party assistants and platforms.
Over the next year, you’ll turn early integrations into first-class, exemplar applications — stable, secure, and opinionated — that are showcased by platform partners and relied on by power users at Brex’s most sophisticated customers. You’ll design how Brex data and actions are safely exposed, how permissions and auditability work across boundaries, and how new capabilities (including richer UI surfaces) are introduced over time.
This is a product role disguised as infrastructure. Success is measured by real usage, trust, and customer reliance — not by the number of integrations shipped.

Requirements

• Experience building and owning production software, including systems that integrate with or depend on third-party platforms.
• Demonstrated technical ownership for user-facing products with real external customers.
• Deep experience with identity, authentication, permissions, and secure data access across system boundaries.
• Proven ability to ship and operate reliable integrations with external APIs and clients outside your control.
• Strong product judgment, written communication, and end-to-end ownership, including accountability for quality and launch readiness.

Nice To Haves

• Experience publishing and maintaining apps or integrations in third-party marketplaces (iOS, Slack, Shopify, GitHub, Chrome, etc.).
• Prior work on administrative or platform-side tooling for ecosystems.
• Familiarity with conversational or agentic interfaces in production environments.

Responsibilities

• Own Brex's MCP Apps for OpenAI, Claude, and other embedders, including roadmap decisions across core and long-tail partners.
• Define the technical, UX, and reliability standards for how Brex surfaces and operates within external AI assistant ecosystems.
• Design and maintain secure, auditable integration patterns, including permissions, read/write access, and acting on behalf of users across third-party environments.
• Build and operate production-grade integrations that remain resilient amid evolving platforms, unpredictable clients, and shifting constraints.
• Partner cross-functionally with Security, Platform, Sales, Enablement, and internal agent teams to ensure integrations are safe, valuable, and well-supported.
• Serve as the center of excellence for reusable AI capabilities across Brex, defining and evangelizing standards, patterns, and shared components that power AI functionality both within the Brex platform and across external ecosystem integrations.

What This Job Offers

• Job Type: Full-time
• Career Level: Mid Level
• Education Level: No Education Listed