diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1c96fb39..12d9ebab 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # Change Log
 
+## Unreleased
+- The SDK internally migrated from `BackendExt` rust backend extension functions to more type-safe `TypesafeBackend`.
+
 ## 1.19.0-beta01
 ### Changed
 - Adopted the latest Bip39 version 1.0.5
diff --git a/backend-lib/src/main/java/cash/z/ecc/android/sdk/internal/jni/RustBackend.kt b/backend-lib/src/main/java/cash/z/ecc/android/sdk/internal/jni/RustBackend.kt
index a8360e07..ed6dcbf5 100644
--- a/backend-lib/src/main/java/cash/z/ecc/android/sdk/internal/jni/RustBackend.kt
+++ b/backend-lib/src/main/java/cash/z/ecc/android/sdk/internal/jni/RustBackend.kt
@@ -12,7 +12,7 @@ import java.io.File
 /**
  * Serves as the JNI boundary between the Kotlin and Rust layers. Functions in this class should
  * not be called directly by code outside of the SDK. Instead, one of the higher-level components
- * should be used such as Wallet.kt or CompactBlockProcessor.kt.
+ * should be used such as WalletCoordinator.kt or CompactBlockProcessor.kt.
  */
 @Suppress("TooManyFunctions")
 class RustBackend private constructor(
@@ -37,13 +37,11 @@ class RustBackend private constructor(
         var dataClearResult = true
         if (clearCache) {
             fsBlockDbRoot.deleteRecursivelySuspend().also { result ->
-                // Twig.debug { "Deletion of the cache files ${if (result) "succeeded" else "failed"}!" }
                 cacheClearResult = result
             }
         }
         if (clearDataDb) {
             dataDbFile.deleteSuspend().also { result ->
-                // Twig.debug { "Deletion of the data database ${if (result) "succeeded" else "failed"}!" }
                 dataClearResult = result
             }
         }
@@ -356,28 +354,6 @@ class RustBackend private constructor(
     override fun getBranchIdForHeight(height: Long): Long =
         branchIdForHeight(height, networkId = networkId)
 
-//    /**
-//     * This is a proof-of-concept for doing Local RPC, where we are effectively using the JNI
-//     * boundary as a grpc server. It is slightly inefficient in terms of both space and time but
-//     * given that it is all done locally, on the heap, it seems to be a worthwhile tradeoff because
-//     * it reduces the complexity and expands the capacity for the two layers to communicate.
-//     *
-//     * We're able to keep the "unsafe" byteArray functions private and wrap them in typeSafe
-//     * equivalents and, eventually, surface any parse errors (for now, errors are only logged).
-//     */
-//     override fun parseTransactionDataList(
-//         tdl: LocalRpcTypes.TransactionDataList
-//     ): LocalRpcTypes.TransparentTransactionList {
-//         return try {
-//             // serialize the list, send it over to rust and get back a serialized set of results that we parse out
-//             // and return
-//             return LocalRpcTypes.TransparentTransactionList.parseFrom(parseTransactionDataList(tdl.toByteArray()))
-//         } catch (t: Throwable) {
-//             twig("ERROR: failed to parse transaction data list due to: $t caused by: ${t.cause}")
-//             LocalRpcTypes.TransparentTransactionList.newBuilder().build()
-//         }
-//     }
-
     /**
      * Exposes all of the librustzcash functions along with helpers for loading the static library.
      */
diff --git a/sdk-lib/src/androidTest/java/cash/z/ecc/android/sdk/internal/storage/block/FileCompactBlockRepositoryTest.kt b/sdk-lib/src/androidTest/java/cash/z/ecc/android/sdk/internal/storage/block/FileCompactBlockRepositoryTest.kt
index dfa554ba..3b597419 100644
--- a/sdk-lib/src/androidTest/java/cash/z/ecc/android/sdk/internal/storage/block/FileCompactBlockRepositoryTest.kt
+++ b/sdk-lib/src/androidTest/java/cash/z/ecc/android/sdk/internal/storage/block/FileCompactBlockRepositoryTest.kt
@@ -1,6 +1,7 @@
 package cash.z.ecc.android.sdk.internal.storage.block
 
-import cash.z.ecc.android.sdk.internal.Backend
+import cash.z.ecc.android.sdk.internal.TypesafeBackend
+import cash.z.ecc.android.sdk.internal.TypesafeBackendImpl
 import cash.z.ecc.android.sdk.internal.ext.deleteRecursivelySuspend
 import cash.z.ecc.android.sdk.internal.ext.existsSuspend
 import cash.z.ecc.android.sdk.internal.ext.listSuspend
@@ -10,7 +11,6 @@ import cash.z.ecc.android.sdk.model.ZcashNetwork
 import cash.z.ecc.fixture.FakeRustBackendFixture
 import cash.z.ecc.fixture.FilePathFixture
 import co.electriccoin.lightwallet.client.fixture.ListOfCompactBlocksFixture
-import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.count
 import kotlinx.coroutines.flow.drop
 import kotlinx.coroutines.flow.first
@@ -29,7 +29,6 @@ import kotlin.test.assertTrue
 
 class FileCompactBlockRepositoryTest {
 
-    @OptIn(ExperimentalCoroutinesApi::class)
     @Before
     fun setup() = runTest {
         val blocksDirectory = FilePathFixture.newBlocksDir()
@@ -40,27 +39,28 @@ class FileCompactBlockRepositoryTest {
         blocksDirectory.mkdirsSuspend()
     }
 
-    @OptIn(ExperimentalCoroutinesApi::class)
     @After
     fun tearDown() = runTest {
         FilePathFixture.newBlocksDir().deleteRecursivelySuspend()
     }
 
     private fun getMockedFileCompactBlockRepository(
-        rustBackend: Backend,
+        backend: TypesafeBackend,
         rootBlocksDirectory: File
     ): FileCompactBlockRepository = runBlocking {
         FileCompactBlockRepository(
             rootBlocksDirectory,
-            rustBackend
+            backend
         )
     }
 
-    @OptIn(ExperimentalCoroutinesApi::class)
     @Test
     fun getLatestHeightTest() = runTest {
         val rustBackend = FakeRustBackendFixture().new()
-        val blockRepository = getMockedFileCompactBlockRepository(rustBackend, FilePathFixture.newBlocksDir())
+        val blockRepository = getMockedFileCompactBlockRepository(
+            TypesafeBackendImpl(rustBackend),
+            FilePathFixture.newBlocksDir()
+        )
 
         val blocks = ListOfCompactBlocksFixture.newFlow()
 
@@ -69,12 +69,14 @@ class FileCompactBlockRepositoryTest {
         assertEquals(blocks.last().height, blockRepository.getLatestHeight()?.value)
     }
 
-    @OptIn(ExperimentalCoroutinesApi::class)
     @Test
     fun findCompactBlockTest() = runTest {
         val network = ZcashNetwork.Testnet
         val rustBackend = FakeRustBackendFixture().new()
-        val blockRepository = getMockedFileCompactBlockRepository(rustBackend, FilePathFixture.newBlocksDir())
+        val blockRepository = getMockedFileCompactBlockRepository(
+            TypesafeBackendImpl(rustBackend),
+            FilePathFixture.newBlocksDir()
+        )
 
         val blocks = ListOfCompactBlocksFixture.newFlow()
 
@@ -99,11 +101,13 @@ class FileCompactBlockRepositoryTest {
         assertNull(blockRepository.findCompactBlock(notPersistedBlockHeight))
     }
 
-    @OptIn(ExperimentalCoroutinesApi::class)
     @Test
     fun writeBlocksTest() = runTest {
         val rustBackend = FakeRustBackendFixture().new()
-        val blockRepository = getMockedFileCompactBlockRepository(rustBackend, FilePathFixture.newBlocksDir())
+        val blockRepository = getMockedFileCompactBlockRepository(
+            TypesafeBackendImpl(rustBackend),
+            FilePathFixture.newBlocksDir()
+        )
 
         assertTrue { rustBackend.metadata.isEmpty() }
 
@@ -114,11 +118,13 @@ class FileCompactBlockRepositoryTest {
         assertEquals(blocks.count(), rustBackend.metadata.size)
     }
 
-    @OptIn(ExperimentalCoroutinesApi::class)
     @Test
     fun writeFewBlocksTest() = runTest {
         val rustBackend = FakeRustBackendFixture().new()
-        val blockRepository = getMockedFileCompactBlockRepository(rustBackend, FilePathFixture.newBlocksDir())
+        val blockRepository = getMockedFileCompactBlockRepository(
+            TypesafeBackendImpl(rustBackend),
+            FilePathFixture.newBlocksDir()
+        )
 
         assertTrue { rustBackend.metadata.isEmpty() }
 
@@ -134,12 +140,14 @@ class FileCompactBlockRepositoryTest {
         assertEquals(reducedBlocksList.count(), rustBackend.metadata.size)
     }
 
-    @OptIn(ExperimentalCoroutinesApi::class)
     @Test
     fun writeBlocksAndCheckStorageTest() = runTest {
         val rustBackend = FakeRustBackendFixture().new()
         val rootBlocksDirectory = FilePathFixture.newBlocksDir()
-        val blockRepository = getMockedFileCompactBlockRepository(rustBackend, rootBlocksDirectory)
+        val blockRepository = getMockedFileCompactBlockRepository(
+            TypesafeBackendImpl(rustBackend),
+            FilePathFixture.newBlocksDir()
+        )
 
         assertTrue { rootBlocksDirectory.exists() }
         assertTrue { rootBlocksDirectory.list()!!.isEmpty() }
@@ -153,14 +161,16 @@ class FileCompactBlockRepositoryTest {
         assertEquals(blocks.count(), rootBlocksDirectory.list()!!.size)
     }
 
-    @OptIn(ExperimentalCoroutinesApi::class)
     @Test
     fun deleteCompactBlockFilesTest() = runTest {
         val rustBackend = FakeRustBackendFixture().new()
         val blocksDirectory = FilePathFixture.newBlocksDir()
         val parentDirectory = blocksDirectory.parentFile!!
 
-        val blockRepository = getMockedFileCompactBlockRepository(rustBackend, blocksDirectory)
+        val blockRepository = getMockedFileCompactBlockRepository(
+            TypesafeBackendImpl(rustBackend),
+            FilePathFixture.newBlocksDir()
+        )
 
         val testedBlocksRange = ListOfCompactBlocksFixture.DEFAULT_FILE_BLOCK_RANGE
         val blocks = ListOfCompactBlocksFixture.newFlow(testedBlocksRange)
@@ -190,11 +200,13 @@ class FileCompactBlockRepositoryTest {
         }
     }
 
-    @OptIn(ExperimentalCoroutinesApi::class)
     @Test
     fun rewindToTest() = runTest {
         val rustBackend = FakeRustBackendFixture().new()
-        val blockRepository = getMockedFileCompactBlockRepository(rustBackend, FilePathFixture.newBlocksDir())
+        val blockRepository = getMockedFileCompactBlockRepository(
+            TypesafeBackendImpl(rustBackend),
+            FilePathFixture.newBlocksDir()
+        )
 
         val testedBlocksRange = ListOfCompactBlocksFixture.DEFAULT_FILE_BLOCK_RANGE
 
@@ -229,7 +241,6 @@ class FileCompactBlockRepositoryTest {
         assertEquals(expectedKeptMetadataCount, keptMetadataBelowRewindHeight.size)
     }
 
-    @OptIn(ExperimentalCoroutinesApi::class)
     @Test
     fun createTemporaryFileTest() = runTest {
         val blocksDir = FilePathFixture.newBlocksDir()
@@ -241,7 +252,6 @@ class FileCompactBlockRepositoryTest {
         assertTrue { file.existsSuspend() }
     }
 
-    @OptIn(ExperimentalCoroutinesApi::class)
     @Test
     fun finalizeFileTest() = runTest {
         val blocksDir = FilePathFixture.newBlocksDir()
diff --git a/sdk-lib/src/androidTest/java/cash/z/ecc/android/sdk/jni/BranchIdTest.kt b/sdk-lib/src/androidTest/java/cash/z/ecc/android/sdk/jni/BranchIdTest.kt
index 310288b8..c08feb61 100644
--- a/sdk-lib/src/androidTest/java/cash/z/ecc/android/sdk/jni/BranchIdTest.kt
+++ b/sdk-lib/src/androidTest/java/cash/z/ecc/android/sdk/jni/BranchIdTest.kt
@@ -2,10 +2,9 @@ package cash.z.ecc.android.sdk.jni
 
 import cash.z.ecc.android.sdk.annotation.MaintainedTest
 import cash.z.ecc.android.sdk.annotation.TestPurpose
-import cash.z.ecc.android.sdk.internal.Backend
-import cash.z.ecc.android.sdk.internal.getBranchIdForHeight
+import cash.z.ecc.android.sdk.internal.TypesafeBackend
+import cash.z.ecc.android.sdk.internal.TypesafeBackendImpl
 import cash.z.ecc.android.sdk.internal.jni.RustBackend
-import cash.z.ecc.android.sdk.internal.network
 import cash.z.ecc.android.sdk.model.BlockHeight
 import cash.z.ecc.android.sdk.model.ZcashNetwork
 import kotlinx.coroutines.runBlocking
@@ -25,15 +24,15 @@ class BranchIdTest internal constructor(
     private val height: BlockHeight,
     private val branchId: Long,
     private val branchHex: String,
-    private val rustBackend: Backend
+    private val backend: TypesafeBackend
 ) {
 
     @Test
     fun testBranchId_Hex() {
-        val branchId = rustBackend.getBranchIdForHeight(height)
+        val branchId = backend.getBranchIdForHeight(height)
         val clientBranch = "%x".format(branchId)
         assertEquals(
-            "Invalid branch Id Hex value for $networkName at height $height on ${rustBackend.network.networkName}",
+            "Invalid branch Id Hex value for $networkName at height $height on ${backend.network.networkName}",
             branchHex,
             clientBranch
         )
@@ -41,9 +40,9 @@ class BranchIdTest internal constructor(
 
     @Test
     fun testBranchId_Numeric() {
-        val actual = rustBackend.getBranchIdForHeight(height)
+        val actual = backend.getBranchIdForHeight(height)
         assertEquals(
-            "Invalid branch ID for $networkName at height $height on ${rustBackend.network.networkName}",
+            "Invalid branch ID for $networkName at height $height on ${backend.network.networkName}",
             branchId,
             actual
         )
@@ -60,21 +59,25 @@ class BranchIdTest internal constructor(
             // However, due to quirks on certain devices, we created this test at the Android level,
             // as a sanity check
             val testnetBackend = runBlocking {
-                RustBackend.new(
-                    File(""),
-                    File(""),
-                    File(""),
-                    File(""),
-                    ZcashNetwork.Testnet.id,
+                TypesafeBackendImpl(
+                    RustBackend.new(
+                        File(""),
+                        File(""),
+                        File(""),
+                        File(""),
+                        ZcashNetwork.Testnet.id,
+                    )
                 )
             }
             val mainnetBackend = runBlocking {
-                RustBackend.new(
-                    File(""),
-                    File(""),
-                    File(""),
-                    File(""),
-                    ZcashNetwork.Mainnet.id,
+                TypesafeBackendImpl(
+                    RustBackend.new(
+                        File(""),
+                        File(""),
+                        File(""),
+                        File(""),
+                        ZcashNetwork.Mainnet.id,
+                    )
                 )
             }
             return listOf(
diff --git a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/SdkSynchronizer.kt b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/SdkSynchronizer.kt
index bf3a5f97..4dad23f1 100644
--- a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/SdkSynchronizer.kt
+++ b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/SdkSynchronizer.kt
@@ -15,9 +15,10 @@ import cash.z.ecc.android.sdk.exception.TransactionEncoderException
 import cash.z.ecc.android.sdk.exception.TransactionSubmitException
 import cash.z.ecc.android.sdk.ext.ConsensusBranchId
 import cash.z.ecc.android.sdk.ext.ZcashSdk
-import cash.z.ecc.android.sdk.internal.Backend
 import cash.z.ecc.android.sdk.internal.SaplingParamTool
 import cash.z.ecc.android.sdk.internal.Twig
+import cash.z.ecc.android.sdk.internal.TypesafeBackend
+import cash.z.ecc.android.sdk.internal.TypesafeBackendImpl
 import cash.z.ecc.android.sdk.internal.block.CompactBlockDownloader
 import cash.z.ecc.android.sdk.internal.db.DatabaseCoordinator
 import cash.z.ecc.android.sdk.internal.db.derived.DbDerivedDataRepository
@@ -94,7 +95,7 @@ class SdkSynchronizer private constructor(
     private val storage: DerivedDataRepository,
     private val txManager: OutboundTransactionManager,
     val processor: CompactBlockProcessor,
-    private val backend: Backend
+    private val backend: TypesafeBackend
 ) : CloseableSynchronizer {
 
     companion object {
@@ -120,7 +121,7 @@ class SdkSynchronizer private constructor(
             repository: DerivedDataRepository,
             txManager: OutboundTransactionManager,
             processor: CompactBlockProcessor,
-            backend: Backend
+            backend: TypesafeBackend
         ): CloseableSynchronizer {
             val synchronizerKey = SynchronizerKey(zcashNetwork, alias)
 
@@ -510,7 +511,7 @@ class SdkSynchronizer private constructor(
 
     // Not ready to be a public API; internal for testing only
     internal suspend fun createAccount(seed: ByteArray): UnifiedSpendingKey =
-        CompactBlockProcessor.createAccount(backend, seed)
+        backend.createAccountAndGetSpendingKey(seed)
 
     /**
      * Returns the current Unified Address for this account.
@@ -634,20 +635,22 @@ internal object DefaultSynchronizerFactory {
         alias: String,
         saplingParamTool: SaplingParamTool,
         coordinator: DatabaseCoordinator
-    ): Backend {
-        return RustBackend.new(
-            coordinator.fsBlockDbRoot(network, alias),
-            coordinator.dataDbFile(network, alias),
-            saplingOutputFile = saplingParamTool.outputParamsFile,
-            saplingSpendFile = saplingParamTool.spendParamsFile,
-            zcashNetworkId = network.id
+    ): TypesafeBackend {
+        return TypesafeBackendImpl(
+            RustBackend.new(
+                coordinator.fsBlockDbRoot(network, alias),
+                coordinator.dataDbFile(network, alias),
+                saplingOutputFile = saplingParamTool.outputParamsFile,
+                saplingSpendFile = saplingParamTool.spendParamsFile,
+                zcashNetworkId = network.id
+            )
         )
     }
 
     @Suppress("LongParameterList")
     internal suspend fun defaultDerivedDataRepository(
         context: Context,
-        rustBackend: Backend,
+        rustBackend: TypesafeBackend,
         databaseFile: File,
         zcashNetwork: ZcashNetwork,
         checkpoint: Checkpoint,
@@ -666,7 +669,10 @@ internal object DefaultSynchronizerFactory {
             )
         )
 
-    internal suspend fun defaultCompactBlockRepository(blockCacheRoot: File, backend: Backend): CompactBlockRepository =
+    internal suspend fun defaultCompactBlockRepository(
+        blockCacheRoot: File,
+        backend: TypesafeBackend
+    ): CompactBlockRepository =
         FileCompactBlockRepository.new(
             blockCacheRoot,
             backend
@@ -676,7 +682,7 @@ internal object DefaultSynchronizerFactory {
         LightWalletClient.new(context, lightWalletEndpoint)
 
     internal fun defaultEncoder(
-        backend: Backend,
+        backend: TypesafeBackend,
         saplingParamTool: SaplingParamTool,
         repository: DerivedDataRepository
     ): TransactionEncoder = TransactionEncoderImpl(backend, saplingParamTool, repository)
@@ -697,7 +703,7 @@ internal object DefaultSynchronizerFactory {
     }
 
     internal fun defaultProcessor(
-        backend: Backend,
+        backend: TypesafeBackend,
         downloader: CompactBlockDownloader,
         repository: DerivedDataRepository,
         birthdayHeight: BlockHeight
diff --git a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/block/CompactBlockProcessor.kt b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/block/CompactBlockProcessor.kt
index 1ab2c490..39323eb1 100644
--- a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/block/CompactBlockProcessor.kt
+++ b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/block/CompactBlockProcessor.kt
@@ -13,35 +13,23 @@ import cash.z.ecc.android.sdk.exception.RustLayerException
 import cash.z.ecc.android.sdk.ext.ZcashSdk
 import cash.z.ecc.android.sdk.ext.ZcashSdk.MAX_BACKOFF_INTERVAL
 import cash.z.ecc.android.sdk.ext.ZcashSdk.POLL_INTERVAL
-import cash.z.ecc.android.sdk.internal.Backend
 import cash.z.ecc.android.sdk.internal.Twig
+import cash.z.ecc.android.sdk.internal.TypesafeBackend
 import cash.z.ecc.android.sdk.internal.block.CompactBlockDownloader
-import cash.z.ecc.android.sdk.internal.createAccountAndGetSpendingKey
 import cash.z.ecc.android.sdk.internal.ext.isNullOrEmpty
 import cash.z.ecc.android.sdk.internal.ext.length
 import cash.z.ecc.android.sdk.internal.ext.retryUpTo
 import cash.z.ecc.android.sdk.internal.ext.retryWithBackoff
 import cash.z.ecc.android.sdk.internal.ext.toHexReversed
-import cash.z.ecc.android.sdk.internal.getBalance
-import cash.z.ecc.android.sdk.internal.getBranchIdForHeight
-import cash.z.ecc.android.sdk.internal.getCurrentAddress
-import cash.z.ecc.android.sdk.internal.getDownloadedUtxoBalance
-import cash.z.ecc.android.sdk.internal.getNearestRewindHeight
-import cash.z.ecc.android.sdk.internal.getVerifiedBalance
-import cash.z.ecc.android.sdk.internal.listTransparentReceivers
 import cash.z.ecc.android.sdk.internal.model.BlockBatch
 import cash.z.ecc.android.sdk.internal.model.DbTransactionOverview
 import cash.z.ecc.android.sdk.internal.model.JniBlockMeta
 import cash.z.ecc.android.sdk.internal.model.ext.from
 import cash.z.ecc.android.sdk.internal.model.ext.toBlockHeight
-import cash.z.ecc.android.sdk.internal.network
 import cash.z.ecc.android.sdk.internal.repository.DerivedDataRepository
-import cash.z.ecc.android.sdk.internal.rewindToHeight
-import cash.z.ecc.android.sdk.internal.validateCombinedChainOrErrorBlockHeight
 import cash.z.ecc.android.sdk.model.Account
 import cash.z.ecc.android.sdk.model.BlockHeight
 import cash.z.ecc.android.sdk.model.PercentDecimal
-import cash.z.ecc.android.sdk.model.UnifiedSpendingKey
 import cash.z.ecc.android.sdk.model.WalletBalance
 import cash.z.ecc.android.sdk.model.ZcashNetwork
 import co.electriccoin.lightwallet.client.ext.BenchmarkingExt
@@ -94,7 +82,7 @@ import kotlin.time.toDuration
 class CompactBlockProcessor internal constructor(
     val downloader: CompactBlockDownloader,
     private val repository: DerivedDataRepository,
-    private val backend: Backend,
+    private val backend: TypesafeBackend,
     minimumHeight: BlockHeight
 ) {
     /**
@@ -627,7 +615,7 @@ class CompactBlockProcessor internal constructor(
                 utxo.index,
                 utxo.script,
                 utxo.valueZat,
-                utxo.height
+                BlockHeight.new(backend.network, utxo.height)
             )
             true
         } catch (t: Throwable) {
@@ -685,7 +673,7 @@ class CompactBlockProcessor internal constructor(
         /**
          * Requests, processes and persists all blocks from the given range.
          *
-         * @param rustBackend the Rust backend component
+         * @param backend the Rust backend component
          * @param downloader the compact block downloader component
          * @param repository the derived data repository component
          * @param network the network in which the sync mechanism operates
@@ -700,7 +688,7 @@ class CompactBlockProcessor internal constructor(
         @VisibleForTesting
         @Suppress("LongParameterList", "LongMethod")
         internal suspend fun runSyncingAndEnhancing(
-            backend: Backend,
+            backend: TypesafeBackend,
             downloader: CompactBlockDownloader,
             repository: DerivedDataRepository,
             network: ZcashNetwork,
@@ -819,7 +807,7 @@ class CompactBlockProcessor internal constructor(
                         enhanceTransactionDetails(
                             range = currentEnhancingRange,
                             repository = repository,
-                            rustBackend = backend,
+                            backend = backend,
                             downloader = downloader
                         ).collect { enhancingResult ->
                             Twig.debug { "Enhancing result: $enhancingResult" }
@@ -917,7 +905,7 @@ class CompactBlockProcessor internal constructor(
         }
 
         @VisibleForTesting
-        internal suspend fun validateBatchOfBlocks(batch: BlockBatch, backend: Backend): BlockProcessingResult {
+        internal suspend fun validateBatchOfBlocks(batch: BlockBatch, backend: TypesafeBackend): BlockProcessingResult {
             Twig.verbose { "Starting to validate batch $batch" }
 
             val result = backend.validateCombinedChainOrErrorBlockHeight(batch.range.length())
@@ -931,7 +919,7 @@ class CompactBlockProcessor internal constructor(
         }
 
         @VisibleForTesting
-        internal suspend fun scanBatchOfBlocks(batch: BlockBatch, backend: Backend): BlockProcessingResult {
+        internal suspend fun scanBatchOfBlocks(batch: BlockBatch, backend: TypesafeBackend): BlockProcessingResult {
             return runCatching {
                 backend.scanBlocks(batch.range.length())
             }.onSuccess {
@@ -980,7 +968,7 @@ class CompactBlockProcessor internal constructor(
         internal suspend fun enhanceTransactionDetails(
             range: ClosedRange<BlockHeight>,
             repository: DerivedDataRepository,
-            rustBackend: Backend,
+            backend: TypesafeBackend,
             downloader: CompactBlockDownloader
         ): Flow<BlockProcessingResult> = flow {
             Twig.debug { "Enhancing transaction details for blocks $range" }
@@ -998,7 +986,7 @@ class CompactBlockProcessor internal constructor(
                 }
 
                 newTxs.filter { it.minedHeight != null }.onEach { newTransaction ->
-                    val trEnhanceResult = enhanceTransaction(newTransaction, rustBackend, downloader)
+                    val trEnhanceResult = enhanceTransaction(newTransaction, backend, downloader)
                     if (trEnhanceResult is BlockProcessingResult.FailedEnhance) {
                         Twig.error { "Encountered transaction enhancing error: ${trEnhanceResult.error}" }
                         emit(trEnhanceResult)
@@ -1013,7 +1001,7 @@ class CompactBlockProcessor internal constructor(
 
         private suspend fun enhanceTransaction(
             transaction: DbTransactionOverview,
-            backend: Backend,
+            backend: TypesafeBackend,
             downloader: CompactBlockDownloader
         ): BlockProcessingResult {
             Twig.debug { "Starting enhancing transaction (id:${transaction.id}  block:${transaction.minedHeight})" }
@@ -1083,7 +1071,7 @@ class CompactBlockProcessor internal constructor(
         private suspend fun decryptTransaction(
             transactionData: ByteArray,
             minedHeight: BlockHeight,
-            backend: Backend,
+            backend: TypesafeBackend,
         ) {
             runCatching {
                 backend.decryptAndStoreTransaction(transactionData)
@@ -1119,27 +1107,22 @@ class CompactBlockProcessor internal constructor(
         internal suspend fun getLastDownloadedHeight(downloader: CompactBlockDownloader) =
             downloader.getLastDownloadedHeight()
 
-        // CompactBlockProcessor is the wrong place for this, but it's where all the other APIs that need
-        //  access to the RustBackend live. This should be refactored.
-        internal suspend fun createAccount(rustBackend: Backend, seed: ByteArray): UnifiedSpendingKey =
-            rustBackend.createAccountAndGetSpendingKey(seed)
-
         /**
          * Get the current unified address for the given wallet account.
          *
          * @return the current unified address of this account.
          */
-        internal suspend fun getCurrentAddress(rustBackend: Backend, account: Account) =
-            rustBackend.getCurrentAddress(account)
+        internal suspend fun getCurrentAddress(backend: TypesafeBackend, account: Account) =
+            backend.getCurrentAddress(account)
 
         /**
          * Get the legacy Sapling address corresponding to the current unified address for the given wallet account.
          *
          * @return a Sapling address.
          */
-        internal suspend fun getLegacySaplingAddress(rustBackend: Backend, account: Account) =
-            rustBackend.getSaplingReceiver(
-                rustBackend.getCurrentAddress(account)
+        internal suspend fun getLegacySaplingAddress(backend: TypesafeBackend, account: Account) =
+            backend.getSaplingReceiver(
+                backend.getCurrentAddress(account)
             )
                 ?: throw InitializeException.MissingAddressException("legacy Sapling")
 
@@ -1148,9 +1131,9 @@ class CompactBlockProcessor internal constructor(
          *
          * @return a transparent address.
          */
-        internal suspend fun getTransparentAddress(rustBackend: Backend, account: Account) =
-            rustBackend.getTransparentReceiver(
-                rustBackend.getCurrentAddress(account)
+        internal suspend fun getTransparentAddress(backend: TypesafeBackend, account: Account) =
+            backend.getTransparentReceiver(
+                backend.getCurrentAddress(account)
             )
                 ?: throw InitializeException.MissingAddressException("legacy transparent")
     }
diff --git a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/BackendExt.kt b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/BackendExt.kt
deleted file mode 100644
index d88b36c0..00000000
--- a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/BackendExt.kt
+++ /dev/null
@@ -1,143 +0,0 @@
-@file:Suppress("TooManyFunctions")
-
-package cash.z.ecc.android.sdk.internal
-
-import cash.z.ecc.android.sdk.internal.model.Checkpoint
-import cash.z.ecc.android.sdk.internal.model.JniBlockMeta
-import cash.z.ecc.android.sdk.model.Account
-import cash.z.ecc.android.sdk.model.BlockHeight
-import cash.z.ecc.android.sdk.model.UnifiedFullViewingKey
-import cash.z.ecc.android.sdk.model.UnifiedSpendingKey
-import cash.z.ecc.android.sdk.model.WalletBalance
-import cash.z.ecc.android.sdk.model.Zatoshi
-import cash.z.ecc.android.sdk.model.ZcashNetwork
-import cash.z.ecc.android.sdk.tool.DerivationTool
-import kotlinx.coroutines.withContext
-
-internal val Backend.network: ZcashNetwork
-    get() = ZcashNetwork.from(networkId)
-
-internal suspend fun Backend.initAccountsTable(vararg keys: UnifiedFullViewingKey) {
-    val ufvks = Array(keys.size) { keys[it].encoding }
-
-    @Suppress("SpreadOperator")
-    return initAccountsTable(*ufvks)
-}
-
-internal suspend fun Backend.initAccountsTableTypesafe(
-    seed: ByteArray,
-    numberOfAccounts: Int
-): List<UnifiedFullViewingKey> {
-    return DerivationTool.getInstance().deriveUnifiedFullViewingKeys(seed, network, numberOfAccounts)
-}
-
-internal suspend fun Backend.initBlocksTable(checkpoint: Checkpoint) = initBlocksTable(
-    checkpoint.height.value,
-    checkpoint.hash,
-    checkpoint.epochSeconds,
-    checkpoint.tree
-)
-
-internal suspend fun Backend.createAccountAndGetSpendingKey(seed: ByteArray): UnifiedSpendingKey = UnifiedSpendingKey(
-    createAccount(seed)
-)
-
-@Suppress("LongParameterList")
-internal suspend fun Backend.createToAddress(
-    usk: UnifiedSpendingKey,
-    to: String,
-    value: Long,
-    memo: ByteArray? = byteArrayOf()
-): Long = createToAddress(
-    usk.account.value,
-    usk.copyBytes(),
-    to,
-    value,
-    memo
-)
-
-internal suspend fun Backend.shieldToAddress(
-    usk: UnifiedSpendingKey,
-    memo: ByteArray? = byteArrayOf()
-): Long = shieldToAddress(
-    usk.account.value,
-    usk.copyBytes(),
-    memo
-)
-
-internal suspend fun Backend.getCurrentAddress(account: Account): String = getCurrentAddress(account.value)
-
-internal suspend fun Backend.listTransparentReceivers(account: Account): List<String> =
-    listTransparentReceivers(account.value)
-
-internal suspend fun Backend.getBalance(account: Account): Zatoshi = Zatoshi(getBalance(account.value))
-
-internal fun Backend.getBranchIdForHeight(height: BlockHeight): Long = getBranchIdForHeight(height.value)
-
-internal suspend fun Backend.getVerifiedBalance(account: Account): Zatoshi = Zatoshi(
-    getVerifiedBalance
-    (account.value)
-)
-
-internal suspend fun Backend.getNearestRewindHeight(height: BlockHeight): BlockHeight = BlockHeight.new(
-    ZcashNetwork.from(networkId),
-    getNearestRewindHeight(height.value)
-)
-
-internal suspend fun Backend.rewindToHeight(height: BlockHeight) = rewindToHeight(height.value)
-
-internal suspend fun Backend.getLatestBlockHeight(): BlockHeight? = getLatestHeight()?.let {
-    BlockHeight.new(
-        ZcashNetwork.from(networkId),
-        it
-    )
-}
-
-internal suspend fun Backend.findBlockMetadata(height: BlockHeight): JniBlockMeta? =
-    findBlockMetadata(height.value)
-
-internal suspend fun Backend.rewindBlockMetadataToHeight(height: BlockHeight) =
-    rewindBlockMetadataToHeight(height.value)
-
-/**
- * @param limit The limit provides an efficient way how to restrict the portion of blocks, which will be validated.
- * @return Null if successful. If an error occurs, the height will be the height where the error was detected.
- */
-internal suspend fun Backend.validateCombinedChainOrErrorBlockHeight(limit: Long?): BlockHeight? =
-    validateCombinedChainOrErrorHeight(limit)?.let {
-        BlockHeight.new(
-            ZcashNetwork.from(networkId),
-            it
-        )
-    }
-
-internal suspend fun Backend.getDownloadedUtxoBalance(address: String): WalletBalance {
-    // Note this implementation is not ideal because it requires two database queries without a transaction, which makes
-    // the data potentially inconsistent.  However the verified amount is queried first which makes this less bad.
-    val verified = withContext(SdkDispatchers.DATABASE_IO) {
-        getVerifiedTransparentBalance(address)
-    }
-    val total = withContext(SdkDispatchers.DATABASE_IO) {
-        getTotalTransparentBalance(
-            address
-        )
-    }
-    return WalletBalance(Zatoshi(total), Zatoshi(verified))
-}
-
-@Suppress("LongParameterList")
-internal suspend fun Backend.putUtxo(
-    tAddress: String,
-    txId: ByteArray,
-    index: Int,
-    script: ByteArray,
-    value: Long,
-    height: BlockHeight
-) = putUtxo(
-    tAddress,
-    txId,
-    index,
-    script,
-    value,
-    height.value
-)
diff --git a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/TypesafeBackend.kt b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/TypesafeBackend.kt
index 91effc70..97274eda 100644
--- a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/TypesafeBackend.kt
+++ b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/TypesafeBackend.kt
@@ -5,12 +5,18 @@ import cash.z.ecc.android.sdk.internal.model.JniBlockMeta
 import cash.z.ecc.android.sdk.model.Account
 import cash.z.ecc.android.sdk.model.BlockHeight
 import cash.z.ecc.android.sdk.model.UnifiedFullViewingKey
+import cash.z.ecc.android.sdk.model.UnifiedSpendingKey
 import cash.z.ecc.android.sdk.model.WalletBalance
 import cash.z.ecc.android.sdk.model.Zatoshi
+import cash.z.ecc.android.sdk.model.ZcashNetwork
+import java.lang.RuntimeException
+import kotlin.jvm.Throws
 
 @Suppress("TooManyFunctions")
 internal interface TypesafeBackend {
 
+    val network: ZcashNetwork
+
     suspend fun initAccountsTable(vararg keys: UnifiedFullViewingKey)
 
     suspend fun initAccountsTable(
@@ -20,6 +26,21 @@ internal interface TypesafeBackend {
 
     suspend fun initBlocksTable(checkpoint: Checkpoint)
 
+    suspend fun createAccountAndGetSpendingKey(seed: ByteArray): UnifiedSpendingKey
+
+    @Suppress("LongParameterList")
+    suspend fun createToAddress(
+        usk: UnifiedSpendingKey,
+        to: String,
+        value: Long,
+        memo: ByteArray? = byteArrayOf()
+    ): Long
+
+    suspend fun shieldToAddress(
+        usk: UnifiedSpendingKey,
+        memo: ByteArray? = byteArrayOf()
+    ): Long
+
     suspend fun getCurrentAddress(account: Account): String
 
     suspend fun listTransparentReceivers(account: Account): List<String>
@@ -47,4 +68,46 @@ internal interface TypesafeBackend {
     suspend fun validateCombinedChainOrErrorBlockHeight(limit: Long?): BlockHeight?
 
     suspend fun getDownloadedUtxoBalance(address: String): WalletBalance
+
+    @Suppress("LongParameterList")
+    suspend fun putUtxo(
+        tAddress: String,
+        txId: ByteArray,
+        index: Int,
+        script: ByteArray,
+        value: Long,
+        height: BlockHeight
+    )
+
+    suspend fun getSentMemoAsUtf8(idNote: Long): String?
+
+    suspend fun getReceivedMemoAsUtf8(idNote: Long): String?
+
+    suspend fun initDataDb(seed: ByteArray?): Int
+
+    /**
+     * @throws RuntimeException as a common indicator of the operation failure
+     */
+    @Throws(RuntimeException::class)
+    suspend fun scanBlocks(limit: Long?)
+
+    suspend fun decryptAndStoreTransaction(tx: ByteArray)
+
+    fun getSaplingReceiver(ua: String): String?
+
+    fun getTransparentReceiver(ua: String): String?
+
+    suspend fun initBlockMetaDb(): Int
+
+    /**
+     * @throws RuntimeException as a common indicator of the operation failure
+     */
+    @Throws(RuntimeException::class)
+    suspend fun writeBlockMetadata(blockMetadata: List<JniBlockMeta>)
+
+    fun isValidShieldedAddr(addr: String): Boolean
+
+    fun isValidTransparentAddr(addr: String): Boolean
+
+    fun isValidUnifiedAddr(addr: String): Boolean
 }
diff --git a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/TypesafeBackendImpl.kt b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/TypesafeBackendImpl.kt
index bede535f..c4c572c1 100644
--- a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/TypesafeBackendImpl.kt
+++ b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/TypesafeBackendImpl.kt
@@ -5,51 +5,185 @@ import cash.z.ecc.android.sdk.internal.model.JniBlockMeta
 import cash.z.ecc.android.sdk.model.Account
 import cash.z.ecc.android.sdk.model.BlockHeight
 import cash.z.ecc.android.sdk.model.UnifiedFullViewingKey
+import cash.z.ecc.android.sdk.model.UnifiedSpendingKey
 import cash.z.ecc.android.sdk.model.WalletBalance
 import cash.z.ecc.android.sdk.model.Zatoshi
+import cash.z.ecc.android.sdk.model.ZcashNetwork
+import cash.z.ecc.android.sdk.tool.DerivationTool
+import kotlinx.coroutines.withContext
 
-// This class is currently unused, although the goal is to swap out usages of BackendExt for this throughout the SDK.
 @Suppress("TooManyFunctions")
 internal class TypesafeBackendImpl(private val backend: Backend) : TypesafeBackend {
-    override suspend fun initAccountsTable(vararg keys: UnifiedFullViewingKey) =
-        backend.initAccountsTable(*keys)
+
+    override val network: ZcashNetwork
+        get() = ZcashNetwork.from(backend.networkId)
+
+    override suspend fun initAccountsTable(vararg keys: UnifiedFullViewingKey) {
+        val ufvks = Array(keys.size) { keys[it].encoding }
+        @Suppress("SpreadOperator")
+        backend.initAccountsTable(*ufvks)
+    }
 
     override suspend fun initAccountsTable(
         seed: ByteArray,
         numberOfAccounts: Int
-    ): List<UnifiedFullViewingKey> = backend.initAccountsTableTypesafe(seed, numberOfAccounts)
+    ): List<UnifiedFullViewingKey> {
+        return DerivationTool.getInstance().deriveUnifiedFullViewingKeys(seed, network, numberOfAccounts)
+    }
 
-    override suspend fun initBlocksTable(checkpoint: Checkpoint) = backend.initBlocksTable(checkpoint)
+    override suspend fun initBlocksTable(checkpoint: Checkpoint) {
+        backend.initBlocksTable(
+            checkpoint.height.value,
+            checkpoint.hash,
+            checkpoint.epochSeconds,
+            checkpoint.tree
+        )
+    }
 
-    override suspend fun getCurrentAddress(account: Account): String = getCurrentAddress(account)
+    override suspend fun createAccountAndGetSpendingKey(seed: ByteArray): UnifiedSpendingKey {
+        return UnifiedSpendingKey(backend.createAccount(seed))
+    }
 
-    override suspend fun listTransparentReceivers(account: Account): List<String> =
-        backend.listTransparentReceivers(account)
+    @Suppress("LongParameterList")
+    override suspend fun createToAddress(
+        usk: UnifiedSpendingKey,
+        to: String,
+        value: Long,
+        memo: ByteArray?
+    ): Long = backend.createToAddress(
+        usk.account.value,
+        usk.copyBytes(),
+        to,
+        value,
+        memo
+    )
 
-    override suspend fun getBalance(account: Account): Zatoshi = backend.getBalance(account)
+    override suspend fun shieldToAddress(
+        usk: UnifiedSpendingKey,
+        memo: ByteArray?
+    ): Long = backend.shieldToAddress(
+        usk.account.value,
+        usk.copyBytes(),
+        memo
+    )
 
-    override fun getBranchIdForHeight(height: BlockHeight): Long = backend.getBranchIdForHeight(height.value)
+    override suspend fun getCurrentAddress(account: Account): String {
+        return backend.getCurrentAddress(account.value)
+    }
 
-    override suspend fun getVerifiedBalance(account: Account): Zatoshi = backend.getVerifiedBalance(account)
+    override suspend fun listTransparentReceivers(account: Account): List<String> {
+        return backend.listTransparentReceivers(account.value)
+    }
 
-    override suspend fun getNearestRewindHeight(height: BlockHeight): BlockHeight =
-        backend.getNearestRewindHeight(height)
+    override suspend fun getBalance(account: Account): Zatoshi {
+        return Zatoshi(backend.getBalance(account.value))
+    }
 
-    override suspend fun rewindToHeight(height: BlockHeight) = backend.rewindToHeight(height)
+    override fun getBranchIdForHeight(height: BlockHeight): Long {
+        return backend.getBranchIdForHeight(height.value)
+    }
 
-    override suspend fun getLatestBlockHeight(): BlockHeight? = backend.getLatestBlockHeight()
+    override suspend fun getVerifiedBalance(account: Account): Zatoshi {
+        return Zatoshi(backend.getVerifiedBalance(account.value))
+    }
 
-    override suspend fun findBlockMetadata(height: BlockHeight): JniBlockMeta? = backend.findBlockMetadata(height)
+    override suspend fun getNearestRewindHeight(height: BlockHeight): BlockHeight {
+        return BlockHeight.new(
+            ZcashNetwork.from(backend.networkId),
+            backend.getNearestRewindHeight(height.value)
+        )
+    }
 
-    override suspend fun rewindBlockMetadataToHeight(height: BlockHeight) = backend.rewindBlockMetadataToHeight(height)
+    override suspend fun rewindToHeight(height: BlockHeight) {
+        backend.rewindToHeight(height.value)
+    }
+
+    override suspend fun getLatestBlockHeight(): BlockHeight? {
+        return backend.getLatestHeight()?.let {
+            BlockHeight.new(
+                ZcashNetwork.from(backend.networkId),
+                it
+            )
+        }
+    }
+
+    override suspend fun findBlockMetadata(height: BlockHeight): JniBlockMeta? {
+        return backend.findBlockMetadata(height.value)
+    }
+
+    override suspend fun rewindBlockMetadataToHeight(height: BlockHeight) {
+        backend.rewindBlockMetadataToHeight(height.value)
+    }
 
     /**
      * @param limit The limit provides an efficient way how to restrict the portion of blocks, which will be validated.
      * @return Null if successful. If an error occurs, the height will be the height where the error was detected.
      */
-    override suspend fun validateCombinedChainOrErrorBlockHeight(limit: Long?): BlockHeight? =
-        backend.validateCombinedChainOrErrorBlockHeight(limit)
+    override suspend fun validateCombinedChainOrErrorBlockHeight(limit: Long?): BlockHeight? {
+        return backend.validateCombinedChainOrErrorHeight(limit)?.let {
+            BlockHeight.new(
+                ZcashNetwork.from(backend.networkId),
+                it
+            )
+        }
+    }
 
-    override suspend fun getDownloadedUtxoBalance(address: String): WalletBalance =
-        backend.getDownloadedUtxoBalance(address)
+    override suspend fun getDownloadedUtxoBalance(address: String): WalletBalance {
+        // Note this implementation is not ideal because it requires two database queries without a transaction, which
+        // makes the data potentially inconsistent.  However the verified amount is queried first which makes this less
+        // bad.
+        val verified = withContext(SdkDispatchers.DATABASE_IO) {
+            backend.getVerifiedTransparentBalance(address)
+        }
+        val total = withContext(SdkDispatchers.DATABASE_IO) {
+            backend.getTotalTransparentBalance(
+                address
+            )
+        }
+        return WalletBalance(Zatoshi(total), Zatoshi(verified))
+    }
+
+    @Suppress("LongParameterList")
+    override suspend fun putUtxo(
+        tAddress: String,
+        txId: ByteArray,
+        index: Int,
+        script: ByteArray,
+        value: Long,
+        height: BlockHeight
+    ) {
+        return backend.putUtxo(
+            tAddress,
+            txId,
+            index,
+            script,
+            value,
+            height.value
+        )
+    }
+
+    override suspend fun getSentMemoAsUtf8(idNote: Long) = backend.getSentMemoAsUtf8(idNote)
+
+    override suspend fun getReceivedMemoAsUtf8(idNote: Long): String? = backend.getReceivedMemoAsUtf8(idNote)
+
+    override suspend fun initDataDb(seed: ByteArray?): Int = backend.initDataDb(seed)
+
+    override suspend fun scanBlocks(limit: Long?) = backend.scanBlocks(limit)
+
+    override suspend fun decryptAndStoreTransaction(tx: ByteArray) = backend.decryptAndStoreTransaction(tx)
+
+    override fun getSaplingReceiver(ua: String): String? = backend.getSaplingReceiver(ua)
+
+    override fun getTransparentReceiver(ua: String): String? = backend.getTransparentReceiver(ua)
+
+    override suspend fun initBlockMetaDb(): Int = backend.initBlockMetaDb()
+
+    override suspend fun writeBlockMetadata(blockMetadata: List<JniBlockMeta>) =
+        backend.writeBlockMetadata(blockMetadata)
+
+    override fun isValidShieldedAddr(addr: String): Boolean = backend.isValidShieldedAddr(addr)
+
+    override fun isValidTransparentAddr(addr: String): Boolean = backend.isValidTransparentAddr(addr)
+
+    override fun isValidUnifiedAddr(addr: String): Boolean = backend.isValidUnifiedAddr(addr)
 }
diff --git a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/db/derived/DerivedDataDb.kt b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/db/derived/DerivedDataDb.kt
index 71c19a5c..06656faa 100644
--- a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/db/derived/DerivedDataDb.kt
+++ b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/db/derived/DerivedDataDb.kt
@@ -2,13 +2,11 @@ package cash.z.ecc.android.sdk.internal.db.derived
 
 import android.content.Context
 import androidx.sqlite.db.SupportSQLiteDatabase
-import cash.z.ecc.android.sdk.internal.Backend
 import cash.z.ecc.android.sdk.internal.NoBackupContextWrapper
 import cash.z.ecc.android.sdk.internal.Twig
+import cash.z.ecc.android.sdk.internal.TypesafeBackend
 import cash.z.ecc.android.sdk.internal.db.ReadOnlySupportSqliteOpenHelper
 import cash.z.ecc.android.sdk.internal.ext.tryWarn
-import cash.z.ecc.android.sdk.internal.initAccountsTable
-import cash.z.ecc.android.sdk.internal.initBlocksTable
 import cash.z.ecc.android.sdk.internal.model.Checkpoint
 import cash.z.ecc.android.sdk.model.UnifiedFullViewingKey
 import cash.z.ecc.android.sdk.model.ZcashNetwork
@@ -44,7 +42,7 @@ internal class DerivedDataDb private constructor(
         @Suppress("LongParameterList", "SpreadOperator")
         suspend fun new(
             context: Context,
-            backend: Backend,
+            backend: TypesafeBackend,
             databaseFile: File,
             zcashNetwork: ZcashNetwork,
             checkpoint: Checkpoint,
diff --git a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/storage/block/FileCompactBlockRepository.kt b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/storage/block/FileCompactBlockRepository.kt
index 373c0abc..d74441cc 100644
--- a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/storage/block/FileCompactBlockRepository.kt
+++ b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/storage/block/FileCompactBlockRepository.kt
@@ -1,8 +1,8 @@
 package cash.z.ecc.android.sdk.internal.storage.block
 
 import androidx.annotation.VisibleForTesting
-import cash.z.ecc.android.sdk.internal.Backend
 import cash.z.ecc.android.sdk.internal.Twig
+import cash.z.ecc.android.sdk.internal.TypesafeBackend
 import cash.z.ecc.android.sdk.internal.ext.createNewFileSuspend
 import cash.z.ecc.android.sdk.internal.ext.deleteRecursivelySuspend
 import cash.z.ecc.android.sdk.internal.ext.deleteSuspend
@@ -13,11 +13,8 @@ import cash.z.ecc.android.sdk.internal.ext.mkdirsSuspend
 import cash.z.ecc.android.sdk.internal.ext.renameToSuspend
 import cash.z.ecc.android.sdk.internal.ext.toHexReversed
 import cash.z.ecc.android.sdk.internal.ext.writeBytesSuspend
-import cash.z.ecc.android.sdk.internal.findBlockMetadata
-import cash.z.ecc.android.sdk.internal.getLatestBlockHeight
 import cash.z.ecc.android.sdk.internal.model.JniBlockMeta
 import cash.z.ecc.android.sdk.internal.repository.CompactBlockRepository
-import cash.z.ecc.android.sdk.internal.rewindBlockMetadataToHeight
 import cash.z.ecc.android.sdk.model.BlockHeight
 import co.electriccoin.lightwallet.client.model.CompactBlockUnsafe
 import kotlinx.coroutines.flow.Flow
@@ -25,7 +22,7 @@ import java.io.File
 
 internal class FileCompactBlockRepository(
     private val blocksDirectory: File,
-    private val backend: Backend
+    private val backend: TypesafeBackend
 ) : CompactBlockRepository {
 
     override suspend fun getLatestHeight() = backend.getLatestBlockHeight()
@@ -139,7 +136,7 @@ internal class FileCompactBlockRepository(
          */
         suspend fun new(
             blockCacheRoot: File,
-            rustBackend: Backend
+            backend: TypesafeBackend
         ): FileCompactBlockRepository {
             // create and check cache directories
             val blocksDirectory = File(blockCacheRoot, BLOCKS_DOWNLOAD_DIRECTORY).also {
@@ -149,9 +146,9 @@ internal class FileCompactBlockRepository(
                 error("${blocksDirectory.path} directory does not exist and could not be created.")
             }
 
-            rustBackend.initBlockMetaDb()
+            backend.initBlockMetaDb()
 
-            return FileCompactBlockRepository(blocksDirectory, rustBackend)
+            return FileCompactBlockRepository(blocksDirectory, backend)
         }
     }
 }
diff --git a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/transaction/TransactionEncoderImpl.kt b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/transaction/TransactionEncoderImpl.kt
index 0bd0c482..c43016a4 100644
--- a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/transaction/TransactionEncoderImpl.kt
+++ b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/transaction/TransactionEncoderImpl.kt
@@ -2,15 +2,11 @@ package cash.z.ecc.android.sdk.internal.transaction
 
 import cash.z.ecc.android.sdk.exception.TransactionEncoderException
 import cash.z.ecc.android.sdk.ext.masked
-import cash.z.ecc.android.sdk.internal.Backend
 import cash.z.ecc.android.sdk.internal.SaplingParamTool
 import cash.z.ecc.android.sdk.internal.Twig
-import cash.z.ecc.android.sdk.internal.createToAddress
-import cash.z.ecc.android.sdk.internal.getBranchIdForHeight
+import cash.z.ecc.android.sdk.internal.TypesafeBackend
 import cash.z.ecc.android.sdk.internal.model.EncodedTransaction
-import cash.z.ecc.android.sdk.internal.network
 import cash.z.ecc.android.sdk.internal.repository.DerivedDataRepository
-import cash.z.ecc.android.sdk.internal.shieldToAddress
 import cash.z.ecc.android.sdk.model.TransactionRecipient
 import cash.z.ecc.android.sdk.model.UnifiedSpendingKey
 import cash.z.ecc.android.sdk.model.Zatoshi
@@ -25,7 +21,7 @@ import cash.z.ecc.android.sdk.model.Zatoshi
  * such as the raw bytes and raw txId.
  */
 internal class TransactionEncoderImpl(
-    private val backend: Backend,
+    private val backend: TypesafeBackend,
     private val saplingParamTool: SaplingParamTool,
     private val repository: DerivedDataRepository
 ) : TransactionEncoder {