Senior Software Engineer, Accounting Engineering

Engineering at Brex

Engineering at Brex is about building systems that scale with speed and intention. Our teams span Software, Data, Security, and IT, and operate with high autonomy and deep collaboration. We tackle hard technical problems, own our outcomes, and push for excellence at every level — from architecture to deployment. It’s an environment where engineering is a craft, and builders become leaders.

What you'll do

As a Senior Software Engineer on the Accounting Engineering team, you will build the platform and product surfaces that turn Brex activity into accurate, usable accounting data. Accounting is a core component of our product offering and often a strategic differentiator. Your focus will be the systems finance teams depend on to close their books: reusable accounting records, rules, and mappings, reliable ERP integrations with NetSuite, QuickBooks, Xero, and others, and AI-native automation that predicts accounting work while keeping customers in control. You will work across APIs, data models, and distributed systems where correctness and auditability are non-negotiable, while collaborating with product teams across Brex to extend accounting capabilities without one-off solutions.

Where you'll work

This role will be based in our São Paulo 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 three coordinated days in the office per week: Monday, Wednesday, and Thursday. As a perk, we also have up to four weeks per year of fully remote work.

Responsibilities

• Build and maintain the core accounting platform, including reusable records, rules, mappings, and versioned APIs that Brex product teams and external partners extend without one-off solutions.
• Own ERP connectivity end-to-end, building and scaling reliable integrations with NetSuite, QuickBooks, Xero, SAP, and Oracle, including sync, error recovery, and rate-limit handling.
• Implement customer-facing close experiences for reviewing, configuring, reconciling, and exporting financial activity in our React/TypeScript dashboard.
• Collaborate with Product, Design, Data Science, and Implementation teams to translate complex accounting and ERP concepts into experiences that feel simple for finance teams.
• Design distributed systems where correctness is non-negotiable, making idempotency, reconciliation, traceability, and proactive issue detection first-class parts of the architecture.
• Own problems end-to-end, from user experience and API design to data models, scalability, and ongoing observability.
• Work with ML models in production, integrating predicted GL coding and mappings into accounting workflows while preserving explainability and human review.
• Participate in on-call rotation and maintain high operational standards for mission-critical systems.

Requirements

• 5+ years of full-time software engineering experience with a focus on backend development.
• 2+ years of experience building systems in a domain where correctness and reliability were core requirements, such as fintech, payments, financial systems, or another regulated industry (e.g. healthcare, legal).
• Strong curiosity for digging deep into the technical problems, and a track record of owning significant technical scope and delivering high quality solutions.
• Experience designing APIs, data models, and platform capabilities that serve many different customer workflows and configurations.
• Proficiency in backend technologies (e.g., Kotlin, Java, TypeScript) and comfort with our stack (Kotlin and Micronaut).
• Experience architecting, developing, and testing full-stack applications end-to-end.
• Comfort working with databases (e.g., PostgreSQL), event streaming (e.g., Kafka), and distributed systems.
• A high bar for engineering standards: code quality, testing, observability, and operational excellence, and a habit of raising that bar in others through review and mentorship.
• Strong written and verbal English communication and interpersonal abilities.

Bonus points

• Direct experience with accounting systems or ERPs such as NetSuite, QuickBooks, Xero, SAP, or Oracle, either building integrations or working with them as a practitioner.
• Familiarity with accounting concepts such as the monthly close, general ledger coding, reconciliation, or double-entry bookkeeping.
• Experience building third-party integrations at scale, including handling partner API limits, schema drift, and asynchronous failure recovery.
• Experience shipping ML- or LLM-powered product features, particularly where explainability and human review matter.
• Experience with platform or API products consumed by other engineering teams or external developers.
• Experience leading technical design across multiple teams or mentoring engineers as a formal or informal tech lead.