Wallet API Tutorial

This tutorial provides a comprehensive guide to using TrustWeave’s Wallet API. You’ll learn how to create wallets, store credentials, organize them, and create presentations.

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dependencies {
    implementation("org.trustweave:common:0.6.0")
    implementation("org.trustweave:trust:0.6.0")
    implementation("org.trustweave:testkit:0.6.0")
}

Result: Wallet APIs, TrustWeave, and testkit factories used in this tutorial.

Tip: Run ./gradlew :distribution:examples:runQuickStartSample (or follow Quick start) for runnable samples aligned with the snippets below.

Prerequisites

Table of Contents

  1. Creating a Wallet
  2. Storing Credentials
  3. Retrieving Credentials
  4. Organizing Credentials
  5. Querying Credentials
  6. Creating Presentations
  7. Lifecycle Management
  8. Advanced Features

Creating a Wallet 

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// Kotlin stdlib
import kotlinx.coroutines.runBlocking

// TrustWeave core
import org.trustweave.trust.TrustWeave
import org.trustweave.trust.dsl.credential.DidMethods
import org.trustweave.trust.dsl.credential.KeyAlgorithms
import org.trustweave.wallet.WalletCreationOptions
import org.trustweave.testkit.services.*
import org.trustweave.core.exception.TrustWeaveException

fun main() = runBlocking {
    // Build TrustWeave instance (for tutorials, using testkit factories)
    val trustWeave = TrustWeave.build {
        keys { provider(IN_MEMORY); algorithm(KeyAlgorithms.ED25519) }
        did { method(DidMethods.KEY) { algorithm(KeyAlgorithms.ED25519) } }
    }

    try {
        val wallet = trustWeave.wallet {
            holder("did:key:holder")
            type("inMemory")
            enablePresentation()
        }.getOrThrow()

        println("Wallet ID: ${wallet.walletId}")
        println("Holder: ${wallet.holderDid}")
    } catch (error: TrustWeaveException) {
        println("Wallet creation failed: ${error.message}")
    }
}

Outcome: Creates a wallet via TrustWeave.wallet { } and unwraps WalletCreationResult with getOrThrow() (see result types).

Same pattern with TrustWeave.build

Use TrustWeave.build { keys { ... }; did { ... }; factories(walletFactory = ...) } when you need explicit KMS/DID/wallet factory wiring instead of defaults-only demos.

Testkit Wallets

BasicWallet and InMemoryWallet remain available for lightweight unit tests:

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import org.trustweave.testkit.credential.BasicWallet
import org.trustweave.testkit.credential.InMemoryWallet

val basic = BasicWallet()
val inMemory = InMemoryWallet(holderDid = "did:key:test-holder")

Outcome: Shows the lightweight testkit wallets you can use in unit tests or prototypes.

Storing Credentials

Basic Storage 

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import org.trustweave.credential.model.vc.VerifiableCredential
import kotlinx.serialization.json.buildJsonObject
import kotlinx.serialization.json.put

// Create a credential
val credential = VerifiableCredential(
    id = "https://example.com/credentials/123",
    type = listOf("VerifiableCredential", "PersonCredential"),
    issuer = "did:key:issuer",
    credentialSubject = buildJsonObject {
        put("id", "did:key:subject")
        put("name", "Alice")
        put("email", "alice@example.com")
    },
    issuanceDate = "2023-01-01T00:00:00Z"
)

// Store it
val credentialId = wallet.store(credential)
println("Stored credential: $credentialId")

Outcome: Persists a credential in the wallet and returns its storage identifier.

Storing Multiple Credentials 

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val credentials = listOf(credential1, credential2, credential3)
val credentialIds = credentials.map { wallet.store(it) }
println("Stored ${credentialIds.size} credentials")

Outcome: Demonstrates bulk storage patterns for credential lists.

Retrieving Credentials

Get by ID 

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val credential = wallet.get(credentialId)
if (credential != null) {
    println("Found credential: ${credential.id}")
} else {
    println("Credential not found")
}

Outcome: Retrieves a stored credential by ID and handles the nullable response.

List All Credentials 

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val allCredentials = wallet.list()
println("Total credentials: ${allCredentials.size}")

Outcome: Lists every credential in the wallet—useful for dashboards or audits.

List with Filter 

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import org.trustweave.wallet.CredentialFilter

val workCredentials = wallet.list(
    filter = CredentialFilter(
        issuer = "did:key:work-issuer",
        type = listOf("WorkCredential")
    )
)

Outcome: Shows how filter criteria narrow the result set without writing manual queries.

Organizing Credentials

Collections

Create collections to group related credentials:

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if (wallet is CredentialOrganization) {
    // Create a collection
    val workCollection = wallet.createCollection(
        name = "Work Credentials",
        description = "Professional credentials and certifications"
    )

    // Add credentials to collection
    wallet.addToCollection(credentialId, workCollection)

    // Get credentials in collection
    val workCreds = wallet.getCredentialsInCollection(workCollection)
    println("Work credentials: ${workCreds.size}")

    // List all collections
    val collections = wallet.listCollections()
    collections.forEach { collection ->
        println("Collection: ${collection.name} (${collection.credentialCount} credentials)")
    }
}

Outcome: Creates collections, adds credentials, and lists collection metadata when the wallet supports organization.

Tags

Tag credentials for easy filtering:

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if (wallet is CredentialOrganization) {
    // Tag a credential
    wallet.tagCredential(credentialId, setOf("important", "verified", "work"))

    // Get tags for a credential
    val tags = wallet.getTags(credentialId)
    println("Tags: $tags")

    // Find credentials by tag
    val importantCreds = wallet.findByTag("important")

    // Get all tags
    val allTags = wallet.getAllTags()
    println("All tags: $allTags")

    // Remove tags
    wallet.untagCredential(credentialId, setOf("work"))
}

Outcome: Demonstrates tagging workflows—ideal for building saved searches or UI filters.

Metadata

Add custom metadata to credentials:

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if (wallet is CredentialOrganization) {
    // Add metadata
    wallet.addMetadata(credentialId, mapOf(
        "source" to "issuer.com",
        "verified" to true,
        "priority" to "high"
    ))

    // Get metadata
    val metadata = wallet.getMetadata(credentialId)
    println("Metadata: ${metadata?.metadata}")

    // Add notes
    wallet.updateNotes(credentialId, "This credential was verified manually")
}

Querying Credentials

Basic Query 

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val credentials = wallet.query {
    byIssuer("did:key:issuer")
    byType("PersonCredential")
    notExpired()
}

Complex Query 

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val validWorkCredentials = wallet.query {
    byTypes("WorkCredential", "EmploymentCredential", "CertificationCredential")
    bySubject("did:key:subject")
    notExpired()
    notRevoked()
    valid() // Has proof, not expired, not revoked
}

Query Examples 

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// Find expired credentials
val expired = wallet.query {
    expired()
}

// Find revoked credentials
val revoked = wallet.query {
    revoked()
}

// Find credentials by issuer and type
val specific = wallet.query {
    byIssuer("did:key:university")
    byType("DegreeCredential")
}

Creating Presentations

Basic Presentation 

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if (wallet is CredentialPresentation) {
    val presentation = wallet.createPresentation(
        credentialIds = listOf(credentialId1, credentialId2),
        holderDid = "did:key:holder",
        options = mapOf("holderDid" to "did:key:holder", "proofType" to "Ed25519Signature2020", "challenge" to "random-challenge-123",
            domain = "example.com"
        )
    )

    println("Created presentation with ${presentation.verifiableCredential.size} credentials")
}

Selective Disclosure

Reveal only specific fields:

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if (wallet is CredentialPresentation) {
    val selectivePresentation = wallet.createSelectiveDisclosure(
        credentialIds = listOf(credentialId),
        disclosedFields = listOf(
            "name",
            "email",
            "credentialSubject.degree.name"
        ),
        holderDid = "did:key:holder",
        options = emptyMap<String, Any?>()
    )
}

Lifecycle Management

Archiving Credentials 

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if (wallet is CredentialLifecycle) {
    // Archive old credentials
    wallet.archive(oldCredentialId)

    // Get archived credentials
    val archived = wallet.getArchived()
    println("Archived credentials: ${archived.size}")

    // Unarchive if needed
    wallet.unarchive(oldCredentialId)
}

Refreshing Credentials 

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if (wallet is CredentialLifecycle) {
    // Refresh a credential (if refresh service available)
    val refreshed = wallet.refreshCredential(credentialId)
    if (refreshed != null) {
        println("Credential refreshed")
    }
}

Advanced Features

Wallet Statistics

Get an overview of your wallet:

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val stats = wallet.getStatistics()
println("""
    Wallet Statistics:
    - Total credentials: ${stats.totalCredentials}
    - Valid credentials: ${stats.validCredentials}
    - Expired credentials: ${stats.expiredCredentials}
    - Revoked credentials: ${stats.revokedCredentials}
    - Collections: ${stats.collectionsCount}
    - Tags: ${stats.tagsCount}
    - Archived: ${stats.archivedCount}
""".trimIndent())

Type-Safe Capability Checking 

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// Check capabilities at compile-time
when {
    wallet is CredentialOrganization && wallet is CredentialPresentation -> {
        // Full-featured wallet
        wallet.createCollection("My Collection")
        wallet.createPresentation(...)
    }
    wallet is CredentialOrganization -> {
        // Organization-only wallet
        wallet.createCollection("My Collection")
    }
    else -> {
        // Basic wallet
        wallet.store(credential)
    }
}

Extension Functions

Use extension functions for elegant code:

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// Organization features
wallet.withOrganization { org ->
    val collectionId = org.createCollection("Work")
    org.tagCredential(credentialId, setOf("important"))
}

// Lifecycle features
wallet.withLifecycle { lifecycle ->
    lifecycle.archive(oldCredentialId)
}

// Presentation features
wallet.withPresentation { presentation ->
    val vp = presentation.createPresentation(...)
}

Wallet Directory

Manage multiple wallets with an instance-scoped directory:

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import org.trustweave.wallet.WalletDirectory

val directory = WalletDirectory()

// Register wallets
val wallet1 = BasicWallet()
val wallet2 = InMemoryWallet()
directory.register(wallet1)
directory.register(wallet2)

// Find wallets
val retrieved = directory.get(wallet1.walletId)
val byDid = directory.getByDid("did:key:wallet")

// Find wallets with specific capabilities
val orgWallets = directory.findByCapability(CredentialOrganization::class)
val walletsWithCollections = directory.findByCapability("collections")

Complete Example

Here’s a complete example combining all features:

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// Kotlin stdlib
import kotlinx.coroutines.runBlocking
import kotlinx.serialization.json.buildJsonObject
import kotlinx.serialization.json.put

// TrustWeave core
import org.trustweave.trust.TrustWeave
import org.trustweave.trust.dsl.credential.DidMethods
import org.trustweave.trust.dsl.credential.KeyAlgorithms
import org.trustweave.credential.model.vc.VerifiableCredential
import org.trustweave.testkit.credential.InMemoryWallet
import org.trustweave.testkit.services.*

fun main() = runBlocking {
    // Create wallet using TrustWeave service API
    // Build TrustWeave instance (for tutorials, using testkit factories)
    val trustWeave = TrustWeave.build {
        keys { provider(IN_MEMORY); algorithm(KeyAlgorithms.ED25519) }
        did { method(DidMethods.KEY) { algorithm(KeyAlgorithms.ED25519) } }
    }
    val wallet = trustWeave.wallet {
        holder("did:key:holder")
        type("inMemory")
    }

    // Store credentials
    val credential1 = createCredential("Alice", "alice@example.com")
    val credential2 = createCredential("Bob", "bob@example.com")

    val id1 = wallet.store(credential1)
    val id2 = wallet.store(credential2)

    // Organize credentials
    val workCollection = wallet.createCollection("Work Credentials")
    wallet.addToCollection(id1, workCollection)
    wallet.tagCredential(id1, setOf("important", "verified"))

    // Query credentials
    val important = wallet.query {
        byIssuer("did:key:issuer")
        valid()
    }

    // Create presentation
    val presentation = wallet.createPresentation(
        credentialIds = listOf(id1),
        holderDid = wallet.holderDid,
        options = mapOf(
            "holderDid" to wallet.holderDid,
            "proofType" to "Ed25519Signature2020"
        )
    )

    // Get statistics
    val stats = wallet.getStatistics()
    println("Wallet has ${stats.totalCredentials} credentials")
}

fun createCredential(name: String, email: String): VerifiableCredential {
    return VerifiableCredential(
        type = listOf("VerifiableCredential", "PersonCredential"),
        issuer = "did:key:issuer",
        credentialSubject = buildJsonObject {
            put("id", "did:key:subject")
            put("name", name)
            put("email", email)
        },
        issuanceDate = "2023-01-01T00:00:00Z"
    )
}

Best Practices

  1. Use type-safe checks (wallet is CredentialOrganization) when possible
  2. Organize credentials early using collections and tags
  3. Query efficiently by combining filters
  4. Use selective disclosure to minimize data exposure
  5. Archive instead of delete to maintain history
  6. Monitor statistics to track wallet health

Next Steps

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