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

# Prerequisites

> What your wallet needs before making a real Atum payment — funds, gas, and allowances for the payer, and a valid receive address for the recipient. Applies whether you use the CLI, the SDK, or the payment-protocol examples.

Before you make a **real** Atum payment — through the [CLI](/get-started/start-building/using-the-cli), the [SDK](/get-started/start-building/build-with-the-sdk), or the [payment-protocol examples](/payment-protocols/overview) — make sure the wallet on each side is ready. Simulated or local test runs move no funds and need none of this.

<Info>
  This page is the checklist of *what* must be in place. [Set up a testnet wallet](/get-started/reference/setup-testnet-wallet) is *how* to get there — funding a wallet with faucets and bridging. And [Choose an environment](/payment-protocols/environments) covers *which* environment to target first.
</Info>

## Payer

The payer signs and funds the payment, so its wallet does the real work. Confirm on the **source** chain:

| Check                    | What it is                                                                                                                                                                                                                                                                                                                                                  | Where to confirm                                                                                                              |
| ------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------- |
| Source network and asset | The chain and token you pay from                                                                                                                                                                                                                                                                                                                            | [Supported networks](/get-started/reference/supported-networks) · [Supported assets](/get-started/reference/supported-assets) |
| Source token balance     | At least the amount plus any markup the payment requires                                                                                                                                                                                                                                                                                                    | Source-chain explorer                                                                                                         |
| Source-chain gas         | Enough for the one-time Permit2 `approve()` — usually the chain's native coin, though some chains (e.g. [Tempo](/get-started/reference/supported-assets#tempo-moderato-assets)) charge gas in tokenized currencies instead. [Settlement gas](/settle-payments/integration-guide#4-fund-your-settler-wallets) is the settlement provider's, not the payer's. | Source-chain explorer                                                                                                         |
| Permit2 allowance        | Approved once on the source token before paying                                                                                                                                                                                                                                                                                                             | [Permit2 and approvals](/get-started/concepts/permit2-and-approvals)                                                          |
| Expected result          | Source token balance **decreases** once settlement completes                                                                                                                                                                                                                                                                                                | Source-chain explorer                                                                                                         |

## Recipient

The recipient is a pure receiver — it holds no keys and moves no funds, so it needs no gas or token balance of its own. Confirm only where the money lands, on the **destination** chain:

| Check                         | What it is                                                        | Where to confirm                                                                                                              |
| ----------------------------- | ----------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------- |
| Destination network and asset | The chain and token you receive                                   | [Supported networks](/get-started/reference/supported-networks) · [Supported assets](/get-started/reference/supported-assets) |
| Receive address               | A valid address on the destination chain                          | Destination-chain explorer                                                                                                    |
| Expected result               | Destination asset balance **increases** by the fulfillment amount | Destination-chain explorer                                                                                                    |

<Warning>
  Match assets by **chain, contract address, and decimals** — not by symbol. Similarly named tokens (native USDC, a bridged `USDC.e`, or a chain-specific tokenized currency like `pathUSD`) are different contracts. See [Wrong token variant](/get-started/support/troubleshooting#wrong-token-variant).
</Warning>

## Next steps

| Topic                         | Link                                                                   |
| ----------------------------- | ---------------------------------------------------------------------- |
| Which environment to target   | [Choose an environment](/payment-protocols/environments)               |
| How to fund a testnet wallet  | [Set up a testnet wallet](/get-started/reference/setup-testnet-wallet) |
| Send your first payment (CLI) | [Try it (CLI)](/get-started/start-building/using-the-cli)              |
| Integrate the SDK             | [Integrate (SDK)](/get-started/start-building/build-with-the-sdk)      |
| Run a payment example         | [Payment protocols](/payment-protocols/overview)                       |