Back to all articles
Technical
API-First Treasury: Building Composable Financial Infrastructure
How REST APIs, webhooks, and event-driven architecture enable modular treasury systems that grow with your business.
18 min read
January 6, 2025
Modern treasury infrastructure must be composable—assembled from best-of-breed components rather than monolithic suites. API-first architecture enables this composability by exposing all treasury operations as programmable interfaces. The Grain & Vault API provides REST endpoints for every treasury function: wallet management, payments, settlements, reporting, and more. This guide explores how API-first design enables modular, scalable treasury systems.
REST API Design Principles
- Resource-oriented: Wallets, Payments, Settlements as first-class resources
- Stateless: Each request contains all necessary context
- Versioned: API versioning ensures backward compatibility
- Idempotent: Safe to retry failed requests without duplication
typescript
// API-First Treasury Operations
const API_BASE = 'https://api.grainandvault.com/v1'
// Create a payment
const payment = await fetch(`${API_BASE}/payments`, {
method: 'POST',
headers: {
'Authorization': `Bearer ${API_KEY}`,
'Idempotency-Key': `pay_${invoiceId}`
},
body: JSON.stringify({
from_wallet: 'wal_abc123',
to_address: 'vendor_wallet_address',
amount: '25000.00',
currency: 'GRAIN',
metadata: { invoice: 'INV-2025-001' }
})
})
// Returns immediately with payment status
// { id: 'pay_xyz789', status: 'completed', settled_at: '2025-01-15T...' }Webhook Architecture
While the REST API provides request/response operations, webhooks enable event-driven architecture. Configure endpoints to receive real-time notifications for payment completions, failed transactions, balance changes, and security events. Webhooks include cryptographic signatures for verification.
Ready to Transform Your Treasury?
Join forward-thinking enterprises using GRAIN for instant, zero-friction payments with protected reserves.