> ## Documentation Index
> Fetch the complete documentation index at: https://docs.polygon.technology/llms.txt
> Use this file to discover all available pages before exploring further.

# Consumer on-ramp and off-ramp

> Fund a crypto wallet via cash-in or bank rails, and withdraw back to a bank.

A user funds their wallet by paying in cash at any of 50,000+ retail locations, which OMS converts to USDC. They hold the USDC on Polygon. When they want to move money out, they can send it onchain to another wallet or external blockchain address, or withdraw it back to a bank account. Funding via bank rails uses a dedicated virtual account for inbound ACH.

This is the core loop for any consumer crypto product: move money in, hold it onchain, move it out. OMS handles the fiat rails, conversion, and compliance on both sides.

**Who this is for:**

* Consumer apps that want to offer crypto-backed savings or spending accounts
* Crypto exchanges and brokers handling retail on/off-ramp volume
* DeFi frontends that need fiat on-ramps for users without existing crypto holdings
* Apps onboarding cash-preferring or unbanked users who fund without a bank account or card

<Note>
  Cash-in funding, crypto-to-crypto sends, bank funding, and bank payouts all run on the OMS API today. Create a virtual account for inbound ACH with `POST /virtual-accounts`, and register the customer's bank account for payouts with `POST /external-accounts`. In sandbox you can exercise inbound ACH with the virtual-account simulate endpoint. The OMS API is in early access: [request access](https://info.polygon.technology/get-early-access?utm_source=docs\&utm_medium=note\&utm_campaign=oms_access) for an API key.
</Note>

***

## How it works

<div style={{border:"1px solid #C8CFE1",borderRadius:"12px",overflow:"hidden",marginBottom:"16px"}}>
  <div style={{background:"linear-gradient(180deg,#EAE4F5 0%,#F6F3FB 100%)",borderBottom:"1px solid #D5C4F2",padding:"10px 16px",fontSize:"11px",fontWeight:"700",color:"#670DE5",letterSpacing:"0.06em",textTransform:"uppercase"}}>On-ramp flow</div>

  <div style={{borderBottom:"1px solid #EEF0F9",padding:"9px 16px",display:"flex",alignItems:"center",gap:"10px"}}>
    <span style={{color:"#929EBA",fontSize:"11px",fontWeight:"700",minWidth:"16px",textAlign:"right"}}>1</span>
    <span style={{background:"#EEF0F9",color:"#48526F",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"600",whiteSpace:"nowrap"}}>App</span>
    <span style={{color:"#670DE5",fontWeight:"700"}}>→</span>
    <span style={{background:"#EAE4F5",color:"#670DE5",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"700",whiteSpace:"nowrap"}}>OMS</span>
    <span style={{fontFamily:"'Geist Mono',ui-monospace,monospace",fontSize:"12px",color:"#141635"}}>POST /cash-ins (cash funding), or fund via a Virtual Account for inbound ACH</span>
  </div>

  <div style={{borderBottom:"1px solid #EEF0F9",padding:"9px 16px",display:"flex",alignItems:"center",gap:"10px"}}>
    <span style={{color:"#929EBA",fontSize:"11px",fontWeight:"700",minWidth:"16px",textAlign:"right"}}>2</span>
    <span style={{background:"#EAE4F5",color:"#670DE5",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"700",whiteSpace:"nowrap"}}>OMS</span>
    <span style={{color:"#670DE5",fontWeight:"700"}}>→</span>
    <span style={{background:"#EEF0F9",color:"#48526F",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"600",whiteSpace:"nowrap"}}>App</span>
    <span style={{fontSize:"13px",color:"#141635"}}>Quote with rate, fees, and expiry window</span>
  </div>

  <div style={{borderBottom:"1px solid #EEF0F9",padding:"9px 16px",display:"flex",alignItems:"center",gap:"10px"}}>
    <span style={{color:"#929EBA",fontSize:"11px",fontWeight:"700",minWidth:"16px",textAlign:"right"}}>3</span>
    <span style={{background:"#EEF0F9",color:"#48526F",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"600",whiteSpace:"nowrap"}}>App</span>
    <span style={{color:"#670DE5",fontWeight:"700"}}>→</span>
    <span style={{background:"#EAE4F5",color:"#670DE5",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"700",whiteSpace:"nowrap"}}>OMS</span>
    <span style={{fontFamily:"'Geist Mono',ui-monospace,monospace",fontSize:"12px",color:"#141635"}}>POST /transactions (quoteId)</span>
  </div>

  <div style={{borderBottom:"1px solid #EEF0F9",padding:"9px 16px",display:"flex",alignItems:"center",gap:"10px"}}>
    <span style={{color:"#929EBA",fontSize:"11px",fontWeight:"700",minWidth:"16px",textAlign:"right"}}>4</span>
    <span style={{background:"#EAE4F5",color:"#670DE5",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"700",whiteSpace:"nowrap"}}>OMS</span>
    <span style={{fontSize:"13px",color:"#141635",marginLeft:"4px"}}>Receives fiat cash, or ACH to a Virtual Account, converts to USDC, credits wallet</span>
  </div>

  <div style={{padding:"9px 16px",display:"flex",alignItems:"center",gap:"10px"}}>
    <span style={{color:"#929EBA",fontSize:"11px",fontWeight:"700",minWidth:"16px",textAlign:"right"}}>5</span>
    <span style={{background:"#EAE4F5",color:"#670DE5",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"700",whiteSpace:"nowrap"}}>OMS</span>
    <span style={{color:"#670DE5",fontWeight:"700"}}>→</span>
    <span style={{background:"#EEF0F9",color:"#48526F",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"600",whiteSpace:"nowrap"}}>App</span>
    <span style={{fontFamily:"'Geist Mono',ui-monospace,monospace",fontSize:"12px",color:"#141635"}}>Webhook: transaction.statusChanged</span>
  </div>
</div>

<div style={{border:"1px solid #C8CFE1",borderRadius:"12px",overflow:"hidden",marginBottom:"24px"}}>
  <div style={{background:"linear-gradient(180deg,#EAE4F5 0%,#F6F3FB 100%)",borderBottom:"1px solid #D5C4F2",padding:"10px 16px",fontSize:"11px",fontWeight:"700",color:"#670DE5",letterSpacing:"0.06em",textTransform:"uppercase"}}>Off-ramp flow</div>

  <div style={{borderBottom:"1px solid #EEF0F9",padding:"9px 16px",display:"flex",alignItems:"center",gap:"10px"}}>
    <span style={{color:"#929EBA",fontSize:"11px",fontWeight:"700",minWidth:"16px",textAlign:"right"}}>1</span>
    <span style={{background:"#EEF0F9",color:"#48526F",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"600",whiteSpace:"nowrap"}}>App</span>
    <span style={{color:"#670DE5",fontWeight:"700"}}>→</span>
    <span style={{background:"#EAE4F5",color:"#670DE5",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"700",whiteSpace:"nowrap"}}>OMS</span>
    <span style={{fontFamily:"'Geist Mono',ui-monospace,monospace",fontSize:"12px",color:"#141635"}}>POST /quotes (wallet source, bank destination)</span>
  </div>

  <div style={{borderBottom:"1px solid #EEF0F9",padding:"9px 16px",display:"flex",alignItems:"center",gap:"10px"}}>
    <span style={{color:"#929EBA",fontSize:"11px",fontWeight:"700",minWidth:"16px",textAlign:"right"}}>2</span>
    <span style={{background:"#EAE4F5",color:"#670DE5",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"700",whiteSpace:"nowrap"}}>OMS</span>
    <span style={{color:"#670DE5",fontWeight:"700"}}>→</span>
    <span style={{background:"#EEF0F9",color:"#48526F",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"600",whiteSpace:"nowrap"}}>App</span>
    <span style={{fontSize:"13px",color:"#141635"}}>Quote with rate, fees, and expiry window</span>
  </div>

  <div style={{borderBottom:"1px solid #EEF0F9",padding:"9px 16px",display:"flex",alignItems:"center",gap:"10px"}}>
    <span style={{color:"#929EBA",fontSize:"11px",fontWeight:"700",minWidth:"16px",textAlign:"right"}}>3</span>
    <span style={{background:"#EEF0F9",color:"#48526F",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"600",whiteSpace:"nowrap"}}>App</span>
    <span style={{color:"#670DE5",fontWeight:"700"}}>→</span>
    <span style={{background:"#EAE4F5",color:"#670DE5",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"700",whiteSpace:"nowrap"}}>OMS</span>
    <span style={{fontFamily:"'Geist Mono',ui-monospace,monospace",fontSize:"12px",color:"#141635"}}>POST /transactions (quoteId)</span>
  </div>

  <div style={{borderBottom:"1px solid #EEF0F9",padding:"9px 16px",display:"flex",alignItems:"center",gap:"10px"}}>
    <span style={{color:"#929EBA",fontSize:"11px",fontWeight:"700",minWidth:"16px",textAlign:"right"}}>4</span>
    <span style={{background:"#EAE4F5",color:"#670DE5",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"700",whiteSpace:"nowrap"}}>OMS</span>
    <span style={{fontSize:"13px",color:"#141635",marginLeft:"4px"}}>Pulls USDC from wallet, initiates ACH or wire transfer to the external account</span>
  </div>

  <div style={{padding:"9px 16px",display:"flex",alignItems:"center",gap:"10px"}}>
    <span style={{color:"#929EBA",fontSize:"11px",fontWeight:"700",minWidth:"16px",textAlign:"right"}}>5</span>
    <span style={{background:"#EAE4F5",color:"#670DE5",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"700",whiteSpace:"nowrap"}}>OMS</span>
    <span style={{color:"#670DE5",fontWeight:"700"}}>→</span>
    <span style={{background:"#EEF0F9",color:"#48526F",padding:"2px 8px",borderRadius:"4px",fontSize:"11px",fontWeight:"600",whiteSpace:"nowrap"}}>App</span>
    <span style={{fontFamily:"'Geist Mono',ui-monospace,monospace",fontSize:"12px",color:"#141635"}}>Webhook: transaction.statusChanged</span>
  </div>
</div>

Both directions use the same quote-then-execute flow. The source is always an OMS wallet, and the customer agrees to a rate and fee breakdown before any money moves. Rates lock at quote time for a short window, so the customer sees exactly what they'll receive.

To move money out as a crypto-to-crypto send, run the same `POST /quotes` then `POST /transactions` flow: the source is the customer's wallet and the destination is another wallet or an external blockchain address. Bank payouts follow the flow above, with the destination referencing an external account, registered with `POST /external-accounts`, by its `ext_` identifier.

***

## OMS resources

| Resource                          | Role                                                                                           |
| --------------------------------- | ---------------------------------------------------------------------------------------------- |
| Customer                          | Identity record with KYC and endorsements                                                      |
| Wallet                            | Custodial USDC balance                                                                         |
| Virtual account                   | Dedicated account number for inbound ACH funding, created with `POST /virtual-accounts`        |
| External account                  | Customer's bank account, registered with `POST /external-accounts` and referenced by `ext_` ID |
| Quote                             | Rate lock with fee breakdown before execution                                                  |
| `fiatAccountToCrypto` transaction | Converts inbound fiat to USDC and credits the wallet                                           |
| `cashToCrypto` transaction        | Converts cash-in funding to USDC and credits the wallet                                        |
| `cryptoToCrypto` transaction      | Sends USDC from the wallet to another wallet or external blockchain address                    |
| `cryptoToFiatAccount` transaction | Pulls USDC from the wallet, delivers fiat via ACH or wire                                      |

***

## Implementation

<CardGroup cols={2}>
  <Card title="Customer onboarding" icon="user-plus" href="/payments/guides/customer-onboarding">
    Create customer records, collect KYC, and provision wallets.
  </Card>

  <Card title="Fiat to crypto" icon="money-bill-transfer" href="/payments/guides/fiat-to-crypto">
    Quote and execute cash-in funding and ACH on-ramps via virtual accounts.
  </Card>

  <Card title="Crypto to fiat" icon="circle-dollar-to-slot" href="/payments/guides/crypto-to-fiat">
    Quote and execute ACH or wire off-ramps.
  </Card>

  <Card title="Bank transfers" icon="building-columns" href="/api-reference/guide-bank-transfers">
    Full walkthrough of both funding and withdrawal flows.
  </Card>
</CardGroup>