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

# Development

> Architecture and usage patterns for the Dfns Go SDK, including authentication, wallets, transfers, signing, dependencies, and project setup.

## Request signing

All state-changing requests made to the Dfns API must be cryptographically signed. The SDK handles this automatically when you configure a signer.

<Info>
  For a detailed explanation of request signing and User Action Challenges, see [Signing requests](/guides/developers/signing-requests).
</Info>

## Authentication tokens

The client requires a valid `AuthToken`. See [Required headers](/api-reference/auth) for details on obtaining tokens.

## KeySigner configuration

The `KeySigner` signs challenges using your private key. It supports Ed25519, ECDSA (secp256k1, P-256), and RSA keys.

```go theme={null}
import "github.com/dfns/dfns-sdk-go/v2/signer"

keySigner, err := signer.NewKeySigner(
    "cr-...",                  // credential ID
    string(privateKeyPEM),     // PEM-encoded private key
)
```

| Parameter       | Description                                                                                                                                                               |
| --------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `credentialID`  | ID of the credential registered with your token. Find it in the Dfns Dashboard under `Settings` > `Service Accounts` or `Settings` > `Personal Access Tokens`.            |
| `privateKeyPEM` | PEM-formatted private key associated with the public key you registered when creating your PAT or Service Account. Supports PKCS#8, PKCS#1 (RSA), and SEC 1 (EC) formats. |

## Available API domains

The client provides typed access to all Dfns API domains:

| Domain               | Description                              |
| -------------------- | ---------------------------------------- |
| `client.Wallets`     | Wallet creation, listing, and management |
| `client.Keys`        | Key management operations                |
| `client.Policies`    | Policy rules and approvals               |
| `client.Permissions` | Access control and permissions           |
| `client.Webhooks`    | Webhook configuration                    |
| `client.Signers`     | Signer management                        |
| `client.Staking`     | Staking operations                       |
| `client.Networks`    | Network information                      |
| `client.Exchanges`   | Exchange integrations                    |
| `client.FeeSponsors` | Fee sponsorship                          |
| `client.Swaps`       | Token swap operations                    |
| `client.Agreements`  | Agreement management                     |
| `client.Allocations` | Allocation management                    |
| `client.Auth`        | Authentication helpers                   |

## Error handling

```go theme={null}
import (
    "errors"
    "fmt"

    dfns "github.com/dfns/dfns-sdk-go/v2"
)

_, err := client.Wallets.GetWallet(ctx, "invalid-wallet-id")
if err != nil {
    var apiErr *dfns.APIError
    if errors.As(err, &apiErr) {
        fmt.Printf("API Error (status %d): %s\n", apiErr.StatusCode, apiErr.Body)
    }
}
```