Every side of a transaction specifies an asset (what kind of money) and a network (how it moves). The same field structure works for both crypto and fiat.
{
"asset": "usdc",
"network": "polygon"
}
Crypto assets and networks
| Asset | Network | Description |
|---|
usdc | polygon | USDC on Polygon Chain, the primary settlement asset |
usdc | ethereum | USDC on Ethereum mainnet |
usdc | solana | USDC on Solana |
btc | bitcoin | Bitcoin |
eth | ethereum | Ether |
Fiat rails
| Asset | Network | Description |
|---|
usd | ach | US dollars via ACH bank transfer |
usd | wire | US dollars via domestic wire |
usd | card | US dollars via debit card (coming soon) |
usd | cash | US dollars via physical cash (GreenDot / AllPoint network) |
eur | sepa | Euros via SEPA Instant |
brl | pix | Brazilian reais via PIX |
inr | upi | Indian rupees via UPI |
mxn | spei | Mexican pesos via SPEI |
gbp | fps | British pounds via Faster Payments |
Supported corridors and rails expand regularly. The tables on this page are the authoritative list.
Exchange rates and FX
When a transaction crosses currencies (e.g., USD to USDC, or USDC to EUR), OMS applies a live exchange rate at quote time. The quote response includes:
rates.exchangeRate: the spot rate usedrates.effectiveRate: the post-fee rate the customer actually receivesexpiresAt: when the locked rate expires
OMS sources liquidity from multiple venues and routes to minimize spread. The fee breakdown shows OMS fees, developer fees, and gas costs separately.
Cash networks
Cash off-ramps use OMS’s partnership with physical cash networks:
- GreenDot: US cash deposits and withdrawals at 90,000+ retail locations (CVS, Walgreens, Walmart)
- OXXO / 7-Eleven / Walmart MX: Cash pickup in Mexico
- AllPoint ATM: Cash withdrawals at 55,000 ATMs
Cash on-ramps generate a deposit code the customer presents at a retail location. OMS monitors for the deposit and auto-creates a fiatToCrypto transaction when cash is received. See Cash-in guide for the full flow. 
