The First Step to Building a Wallet App on Stellar with the Wallet SDK

This guide is available on four different programming languages: Typescript, Kotlin, Flutter (Dart) and Swift. You can change the shown version on each page via the buttons above.

Installation

First, you need to add the SDK dependency to your project.

TypeScript
Kotlin
Flutter
Swift

yarn add @stellar/typescript-wallet-sdk

// gradle.kts
implementation("org.stellar:wallet-sdk:[version]")

You can get the latest available version on the project GitHub page

// pubspec.yaml
stellar_wallet_flutter_sdk: ^1.0.6
stellar_flutter_sdk: ^2.1.3

You can get the latest available version on the project GitHub page

Working with the SDK

Let’s start with the main class that provides all SDK functionality. It’s advised to have a singleton wallet object shared across the application. Creating a wallet with a default configuration connected to Stellar’s Testnet is simple:

Kotlin
TypeScript
Flutter
Swift

val wallet = Wallet(StellarConfiguration.Testnet)

let wallet = walletSdk.Wallet.TestNet();

var wallet = Wallet.testNet;

let wallet = Wallet.testNet

The wallet instance can be further configured. For example, to connect to the public network:

Kotlin
TypeScript
Flutter
Swift

val walletTestnet = Wallet(StellarConfiguration(Network.TESTNET, "https://horizon-testnet.stellar.org"))

There is one more available configuration for a wallet that allows it to configure internal logic of the SDK. For example, to test with local servers on an HTTP protocol, HTTP can be manually enabled.

val walletCustom = Wallet(
  StellarConfiguration.Testnet,
  ApplicationConfiguration { defaultRequest { url { protocol = URLProtocol.HTTP } } }
)

let wallet = new Wallet({
  stellarConfiguration: StellarConfiguration.MainNet(),
});

var wallet = Wallet(StellarConfiguration.publicNet);

let wallet = Wallet(stellarConfig: StellarConfig.publicNet)

Configuring the Client

Kotlin
TypeScript
Flutter

The Kotlin wallet SDK uses the ktor client for all network requests (excluding Horizon, where the Stellar SDK’s HTTP client is used). Currently, the okhttp engine is configured to be used with the client. You can read more about how to configure the ktor client here.For example, the client can be globally configured:

val walletCustomClient =
  Wallet(
    StellarConfiguration.Testnet,
    ApplicationConfiguration(
      defaultClientConfig = {
        engine { this.config { this.connectTimeout(Duration.ofSeconds(10)) } }
        install(HttpRequestRetry) {
          retryOnServerErrors(maxRetries = 5)
          exponentialDelay()
        }
      }
    )
  )

This Kotlin code will set the connect timeout to ten seconds via the okhttp configuration and also installs the retry plugin. You can also specify client configuration for specific wallet SDK classes.For example, to change connect timeout when connecting to some anchor server:

val anchorCustomClient =
  walletCustomClient.anchor("example.com") {
    engine { this.config { this.connectTimeout(Duration.ofSeconds(30)) } }
  }

Closing Resources

After the wallet class is no longer used, it’s necessary to close all clients used by it. While in some applications it may not be required (e.g. the wallet lives for the whole lifetime of the application), in other cases it can be required. If your wallet class is short-lived, it’s recommended to close client resources using a close function:

fun closeWallet() {
  wallet.close()
}

The Typescript wallet SDK uses the axios client for all network requests. You can read more about how to configure the axios client here.For example, we can configure our axios client to be globally configured with a timeout:

const customClient: AxiosInstance = axios.create({
  timeout: 1000,
});
let appConfig = new ApplicationConfiguration(DefaultSigner, customClient);
let wal = new Wallet({
  stellarConfiguration: StellarConfiguration.TestNet(),
  applicationConfiguration: appConfig,
});

You can find more configure options here.

The Flutter Wallet SDK uses the standard Client from the http package for all network requests (excluding Horizon, where the Flutter Stellar SDK’s HTTP client is used).Optionally, you can set your own client from http package to be used across the app.The client can be globally configured:

import 'package:http/http.dart';
// ...

// init and configure your HTTP client
// var myClient = ...

// set as default HTTP client
var appConfig = ApplicationConfiguration(defaultClient: myClient);
var walletCustomClient = Wallet(StellarConfiguration.testNet, applicationConfiguration: appConfig);

Some test cases of this SDK use for example the MockClient.

Stellar Basics

The wallet SDK provides some extra functionality on top of the existing Horizon SDK. For interaction with the Stellar network, the wallet SDK covers only the basics used in a typical wallet flow. For more advanced use cases, the underlying Horizon SDK should be used instead. To interact with the Horizon instance configured in the previous steps, simply do:

Kotlin
TypeScript
Flutter
Swift

val stellar = wallet.stellar()

const stellar = wallet.stellar();

var stellar = wallet.stellar();

let stellar = wallet.stellar

This example will create a Stellar class that manages the connection to Horizon service.

Default configuration connects to the public Stellar Horizon instance. You can change this behavior as described above.

You can read more about working with the Stellar network in the respective section.

Anchor Basics

Primary use of the SDK is to provide an easy way to connect to anchors via sets of protocols known as SEPs. Let’s look into connecting to the Stellar test anchor:

Kotlin
TypeScript
Flutter
Swift

val anchor = wallet.anchor("https://testanchor.stellar.org")

let anchor = wallet.anchor({ homeDomain: "testanchor.stellar.org" });

var anchor = wallet.anchor("testanchor.stellar.org")

let anchor = wallet.anchor(homeDomain: "testanchor.stellar.org")

TypeScript

If the anchor home domain uses http, then you need to set the allowHttp flag when creating the anchor:

let anchor = wallet.anchor({ homeDomain: "example.com", allowHttp: true });

This can only be used on Testnet.

And the most basic interaction of fetching a SEP-1: Stellar Info File:

Kotlin
TypeScript
Flutter
Swift

suspend fun anchorToml(): TomlInfo {
  return anchor.getInfo()
}

let resp = await anchor.sep1();

var resp = await anchor.sep1();

let resp = try await anchor.sep1

Below you can find all the SEPs the anchor class currently supports:

SEP-1: Stellar Info File as shown above
SEP-10: explored on Stellar Authentication section
SEP-24: explored on Hosted Deposit and Withdrawal section
SEP-6: explored on Programmatic Deposit and Withdrawal section
SEP-12: explored on Providing KYC info subsection
SEP-38: explored on Quote section

Besides the SEPs supported by the anchor class the wallet SDK also has support for the SEP-7 protocol which is explored on URI Scheme to facilitate delegated signing section.

​Installation

​Working with the SDK

​Configuring the Client

​Closing Resources

​Stellar Basics

​Anchor Basics

Installation

Working with the SDK

Configuring the Client

Closing Resources

Stellar Basics

Anchor Basics