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

# Crypto transfer integration overview (50+ blockchains)

> Build native crypto on/off-ramps across 50+ blockchain networks, with on-chain, off-chain, and simulated execution modes for deposits and withdrawals.

Power native crypto on/off-ramp experiences across 50+ blockchain networks.

## Key concepts

* **Deposits** are detected automatically when incoming funds arrive at the generated deposit address. No quote is required.
* **Withdrawals** are quote-based — the user must confirm a quote before the transaction is created and broadcast.
* **Execution modes** — transactions can be processed on-chain, off-chain (between Uphold users), or in simulated mode (sandbox only).
* **Transaction rules** — some quotes may include requirements (e.g., Travel Rule) that must be resolved before creating the transaction. On-hold transactions may require pending RFIs to be resolved.

## Start building

<CardGroup cols={2}>
  <Card title="Deposit via API" icon="code" href="/developer-guides/crypto-transfers/deposit/via-rest-api">
    Generate a deposit address and monitor for incoming on-chain transfers.
  </Card>

  <Card title="Deposit via Widget" icon="puzzle-piece" href="/developer-guides/crypto-transfers/deposit/via-payment-widget">
    Let users select a crypto network and receive deposit instructions with a low-code, embeddable widget.
  </Card>

  <Card title="Withdrawal via API" icon="code" href="/developer-guides/crypto-transfers/withdrawal/via-rest-api">
    Create and broadcast a crypto withdrawal to an external address.
  </Card>

  <Card title="Withdrawal via Widget" icon="puzzle-piece" href="/developer-guides/crypto-transfers/withdrawal/via-payment-widget">
    Let users select a network and enter their address with a low-code, embeddable widget.
  </Card>
</CardGroup>