# `X402.Paywall.Default`
[🔗](https://github.com/cardotrejos/x402/blob/v0.9.0/lib/x402/paywall/default.ex#L1)

Self-contained HTML paywall page for browser-facing 402 responses.

Renders a single lean page — inline CSS, no external requests, no build
step — from a v2 `PaymentRequired` payload:

  * the resource description plus amount, asset, network, and recipient
    for every advertised payment option
  * the exact Base64 `PAYMENT-REQUIRED` header value for tooling, with
    manual retry instructions
  * a minimal EIP-1193 (`window.ethereum`) payment flow for `"exact"` EVM
    options using the default `eip3009` asset transfer method: connect a
    wallet, sign the `TransferWithAuthorization` typed data via
    `eth_signTypedData_v4`, assemble the v2 `PaymentPayload`, and retry the
    request with a `PAYMENT-SIGNATURE` header

Without a browser wallet — or when no advertised option is wallet-payable —
the page degrades to the requirement details and the manual header
instructions. All interpolated values are HTML-escaped and the embedded
configuration JSON is encoded script-safe, so route descriptions and
service names cannot inject markup.

Configure it through `X402.Plug.PaymentGate`:

    plug X402.Plug.PaymentGate,
      paywall: X402.Paywall.Default,
      routes: [...]

# `network_display_name`
*since 0.6.0* 

```elixir
@spec network_display_name(String.t()) :: String.t()
```

Returns a human-readable display name for a CAIP-2 network identifier.

## Examples

    iex> X402.Paywall.Default.network_display_name("eip155:8453")
    "Base"

    iex> X402.Paywall.Default.network_display_name("eip155:999999")
    "EVM chain 999999"

    iex> X402.Paywall.Default.network_display_name("otherchain:mainnet")
    "otherchain:mainnet"

# `render`
*since 0.6.0* 

```elixir
@spec render(map(), X402.Paywall.conn_info()) :: {:ok, iodata()} | {:error, term()}
```

Renders the default HTML paywall page.

Returns `{:error, reason}` when the payload cannot be encoded as a
`PAYMENT-REQUIRED` header value (see `X402.PaymentRequired.encode/1`).

## Examples

    iex> payment_required = %{
    ...>   "x402Version" => 2,
    ...>   "error" => "PAYMENT-SIGNATURE header is required",
    ...>   "resource" => %{
    ...>     "url" => "https://example.com/premium",
    ...>     "description" => "Premium report",
    ...>     "mimeType" => "application/json"
    ...>   },
    ...>   "accepts" => [
    ...>     %{
    ...>       "scheme" => "exact",
    ...>       "network" => "eip155:84532",
    ...>       "amount" => "10000",
    ...>       "asset" => "0x036CbD53842c5426634e7929541eC2318f3dCF7e",
    ...>       "payTo" => "0x209693Bc6afc0C5328bA36FaF03C514EF312287C",
    ...>       "maxTimeoutSeconds" => 60,
    ...>       "extra" => %{"name" => "USDC", "version" => "2"}
    ...>     }
    ...>   ],
    ...>   "extensions" => %{}
    ...> }
    iex> conn_info = %{method: "GET", request_path: "/premium", status: 402}
    iex> {:ok, html} = X402.Paywall.Default.render(payment_required, conn_info)
    iex> html =~ "Premium report" and html =~ "Base Sepolia"
    true

---

*Consult [api-reference.md](api-reference.md) for complete listing*