Brex API
Brex is a financial platform for startups and growing companies offering corporate cards, expense management, business accounts, and vendor payments. Its API provides programmatic access to card management, transactions, expense submissions, vendor payments, and spend limit controls.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
Corporate spend management API. OAuth2 with granular scopes (expenses, payments, cards). Financial data — use minimal scopes. Webhook signatures for event validation.
⚡ Reliability
Best When
An agent needs to manage corporate card spend, automate expense workflows, or issue/manage cards programmatically for a startup or growing company on Brex.
Avoid When
The company uses Ramp, Divvy, or another expense platform, or is not eligible for Brex (typically requires VC backing or significant revenue).
Use Cases
- • Automated expense categorization and receipt matching
- • Corporate card issuance and limit management for employees
- • Vendor payment automation (ACH, wires, checks)
- • Budget and spend limit enforcement
- • Real-time transaction monitoring and alerting
- • Expense report generation and accounting sync
Not For
- • Personal banking (Brex is business-only)
- • Small businesses below Brex's eligibility requirements
- • International payments in unsupported currencies
- • High-volume consumer payments (use Stripe)
Interface
Authentication
OAuth2 for user-authorized access with granular scopes (transactions.readonly, cards.write, payments.write, etc.). Machine-to-machine auth available via client credentials grant for internal integrations. API tokens can be generated directly in the Brex dashboard for simpler use cases.
Pricing
Brex makes money on interchange fees from card transactions. API access is included free for all Brex customers. No usage-based API pricing.
Agent Metadata
Known Gotchas
- ⚠ Brex eligibility requirements mean not all businesses can access the platform — API is only useful if the company is already a Brex customer
- ⚠ Card limits and spend controls may need human approval for changes above certain thresholds
- ⚠ Payment status is asynchronous — ACH and wire transfers are not immediate; agents must poll or use webhooks
- ⚠ Transaction data for card purchases may have a delay before appearing in API
- ⚠ OAuth token scopes must be carefully configured — overly broad scopes are a security risk on corporate finance APIs
- ⚠ Webhook payload verification is required — HMAC signing must be validated
- ⚠ Some operations (issuing new cards) may trigger compliance checks that delay or reject the operation
Alternatives
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Scores are editorial opinions as of 2026-03-06.