Register a Brex developer application to obtain client credentials; authenticate using OAuth 2.0 with the required scopes for transactions and expenses
Call the Transactions API to retrieve card transaction records; filter by date range and optionally by merchant category to isolate travel spend
Call the Expenses API to retrieve enriched expense objects, which include accounting codes, merchant data, receipt links, and an optional trip ID field for travel-linked expenses
Join transaction and expense records on the shared identifier to build a unified travel spend view with both raw transaction data and any manager-coded accounting fields
Subscribe to the Webhooks API for expense and transaction events to receive near-real-time notifications when new travel charges post or expense coding changes
Export the joined dataset to your accounting or ERP system, using the trip ID field to group charges by business trip for per-trip P&L reporting
Known gotchas
The Expenses API and Transactions API are separate surfaces with different data shapes; an expense object enriches a transaction but the two must be joined — not assumed to always have a 1:1 relationship
Travel API is listed in Brex documentation as a distinct resource; confirm which endpoints are available under your specific Brex plan, as some APIs are gated by product tier
Webhook event delivery may lag behind the transaction API; do not rely on webhooks alone for time-sensitive reconciliation cutoffs — use polling as a fallback
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp