Brex is a battle-tested corporate spend platform that has quietly become the default financial operating system for high-growth tech companies. Its AI handles expense categorization, receipt matching, and financial insights without requiring a finance degree to configure. The Capital One acquisition adds a level of institutional backing that few fintechs can claim. Glean is an enterprise AI search layer — think of it as a brilliant librarian who has read every document, Slack thread, and Salesforce note in your company and can surface exactly what you need in seconds. Its infrastructure is genuinely impressive, with deep integrations, MCP support, and a $7.2B valuation that signals the market believes in the category. The meaningful difference is purpose: Brex manages money flow, Glean manages information flow. They rarely compete for the same budget line. Brex has a free entry point and is operational in days; Glean requires an enterprise sales cycle and a real change-management effort to realize its value. Choose Brex if your immediate pain is spend control, expense automation, or corporate card management — especially if you're not yet enterprise-scale. Choose Glean if you're a large organization hemorrhaging productivity because institutional knowledge is siloed across dozens of tools and finding the right document feels like archaeology.