# FAQ

#### Do I need to change my API code?

No. Point xPay at your existing HTTP endpoint and set pricing. We handle x402 payment verification and proxying.

#### What tokens are supported?

Any SPL token by mint address. USDC on Solana is the default/recommended.

#### How do agents discover my tools?

Your endpoints become MCP tools under `/mcp/:username`. xPay also provides a marketplace listing.

#### When do I get paid?

Per-request, instantly, after payment verification. Funds settle directly to your wallet.

#### Can I control auth to my upstream API?

Yes. Provide optional custom auth headers that xPay will add when forwarding requests.

#### How are prices represented?

`paymentAmount` is a decimal in the token’s standard units (e.g., `0.05` USDC).

#### Is there a sandbox?

Use low `paymentAmount` and local backend. Prefer a dedicated Solana RPC (`SOLANA_RPC_URL`) during testing.