> ## Documentation Index
> Fetch the complete documentation index at: https://docs.x402x.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Payment types

> Differences and choices among EIP-3009, Permit, and Permit2

## Comparison

| Feature     | EIP-3009        | EIP-2612 Permit          | Permit2      |
| ----------- | --------------- | ------------------------ | ------------ |
| Support     | Medium (native) | High (mainstream ERC-20) | General      |
| Nonce       | Random 32B      | Contract nonce           | Flexible     |
| Typical use | USDC native     | Standard ERC-20          | DeFi/general |

## Recommendations

* If natively supports EIP-3009 → choose `eip3009`
* Standard ERC-20 → choose `permit`
* Unsure/general purpose → let the client auto-select or use `permit2`

## Structures reference

See:

* `parameters-responses/core/payment-payload`
* `parameters-responses/core/payment-requirements`