Java SDK development

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.

For a detailed explanation of request signing and User Action Challenges, see Signing requests.

Authentication tokens

The client requires a valid authToken. See Required headers for details on obtaining tokens.

KeySigner configuration

The KeySigner class provides factory methods for each supported key type. Each method takes a credential ID and the private key bytes:

import co.dfns.sdk.auth.*;

// Ed25519 — raw 32-byte seed
Signer signer = KeySigner.fromEd25519PrivateKey("cr-...", ed25519Seed);

// ECDSA P-256 — PKCS#8 DER encoded
Signer signer = KeySigner.fromEcdsaP256PrivateKey("cr-...", p256DerBytes);

// secp256k1 — raw 32-byte big-endian scalar
Signer signer = KeySigner.fromSecp256k1PrivateKey("cr-...", secp256k1Bytes);

// RSA — PKCS#8 DER encoded
Signer signer = KeySigner.fromRsaPrivateKey("cr-...", rsaDerBytes);

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`.
`privateKeyBytes`	Private key bytes in the format expected by the factory method (see table below).

Factory method	Key format
`fromEd25519PrivateKey`	Raw 32-byte seed
`fromEcdsaP256PrivateKey`	PKCS#8 DER encoded
`fromSecp256k1PrivateKey`	Raw 32-byte big-endian scalar
`fromRsaPrivateKey`	PKCS#8 DER encoded

If you have a PEM file, strip the header/footer lines and Base64-decode the content to get the DER bytes.

Sync vs async clients

The SDK provides both synchronous and asynchronous clients:

import co.dfns.sdk.*;

DfnsClientConfig config = DfnsClientConfig.builder()
    .authToken("your-auth-token")
    .signer(signer)
    .build();

// Synchronous
try (DfnsClient client = new DfnsClient(config)) {
    var wallets = client.wallets.listWallets(new co.dfns.sdk.wallets.model.ListWalletsQuery());
}

// Asynchronous — methods return CompletableFuture
try (DfnsAsyncClient asyncClient = new DfnsAsyncClient(config)) {
    var walletsFuture = asyncClient.wallets.listWallets(new co.dfns.sdk.wallets.model.ListWalletsQuery());
    var wallets = walletsFuture.join();
}

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
`client.payouts`	Payout operations

Error handling

import co.dfns.sdk.*;

try {
    var wallet = client.wallets.getWallet("invalid-wallet-id");
} catch (DfnsException e) {
    System.out.printf("HTTP %d: %s (code: %s, requestId: %s)%n",
        e.getHttpStatus(),
        e.getErrorMessage(),
        e.getDfnsErrorCode(),
        e.getRequestId());
}

Backend SDKs

Frontend SDKs

Request signing

Authentication tokens

KeySigner configuration

Sync vs async clients

Available API domains

Error handling

​Request signing

​Authentication tokens

​KeySigner configuration

​Sync vs async clients

​Available API domains

​Error handling

Request signing

Authentication tokens

KeySigner configuration

Sync vs async clients

Available API domains

Error handling