Senior Engineer, AI - Brex Assistant

### Senior Engineer, AI - Brex Assistant#### Seattle, Washington, United States Senior Engineer, AI - Brex Assistant
** Why join us
** 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 Door Dash, 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 at Brex
** 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.
** What you’ll do
** You’ll be the senior technical owner of the Brex Assistant: a consumer-facing conversation product and will lead the rollout of the Assistant experience — defining what “great” looks like, sequencing capabilities deliberately, and shipping a product that is reliable, opinionated, and genuinely useful. You’ll write a significant amount of production code, set the quality bar, and shape how agentic systems integrate with Brex’s core workflows.

This is a deeply product-driven role. Success is measured by better outcomes for customers — higher-quality expense documentation, stronger policy compliance, and less time spent clicking around  — not by novelty or research output.
** Where you’ll work
** This role will be based in our Seattle office. We are a hybrid environment that combines the energy and connections of being in the office with the benefits and flexibility of working from home. We currently require a minimum of two coordinated days in the office per week, Wednesday and Thursday. Starting February 2, 2026, we will require three days per week in office - Monday, Wednesday and Thursday.

As a perk, we also have up to four weeks per year of fully remote work!
** Responsibilities
* ** Own the end-to-end conversational experience for the Brex Assistant, including both outbound system-initiated interactions and inbound mobile chat.
* Act as the technical and product bar-setter for the team, making and executing hard sequencing decisions for assistant capabilities (e.g., memory, merchant data, preferences).
* Write high-quality, production-grade code while shaping architecture and interfaces for agentic workflows, partnering closely with Spend/Expense teams to influence core Brex workflows.
* Set and enforce a high bar for reliability, correctness, and UX in a non-deterministic system, collaborating with infrastructure and security teams for deep integration.
* Establish team norms and best practices for building agentic products, focusing on over communication, validation, and quality control.
** Requirements
* ** Proven experience building and owning user-facing software products in complex, real-world domains.
* Established experience as a Staff / Senior Staff engineer or hands-on Tech Lead; prior people management experience is a strong plus.
* Strong product judgment: a track record of making hard tradeoffs, sticking to them, and delivering outcomes under real constraints.
* Experience building systems that must be reliable despite messy inputs — whether from users, non-deterministic systems, or both.
* Ability to independently own UX and roadmap decisions, build simple and robust user-centric software, and mentor junior…