diff --git a/examples/cis2/transfer.ts b/examples/cis2/transfer.ts
index 59c694863..068d8caee 100644
--- a/examples/cis2/transfer.ts
+++ b/examples/cis2/transfer.ts
@@ -106,7 +106,7 @@ const client = createConcordiumClient(
     const txHash = await contract.transfer(
         {
             senderAddress: from,
-            energy: Energy.create(10000n),
+            energy: Energy.create(10000),
         },
         {
             from,
diff --git a/examples/cis2/updateOperator.ts b/examples/cis2/updateOperator.ts
index 8a02fffd1..aa205d774 100644
--- a/examples/cis2/updateOperator.ts
+++ b/examples/cis2/updateOperator.ts
@@ -86,7 +86,7 @@ const client = createConcordiumClient(
     const txHash = await contract.updateOperator(
         {
             senderAddress: owner,
-            energy: Energy.create(10000n),
+            energy: Energy.create(10000),
         },
         {
             type: cli.flags.updateType as 'add' | 'remove',
diff --git a/examples/cis4/registerCredential.ts b/examples/cis4/registerCredential.ts
index 720aeb368..8e3109934 100644
--- a/examples/cis4/registerCredential.ts
+++ b/examples/cis4/registerCredential.ts
@@ -137,7 +137,7 @@ const signer = buildAccountSigner(wallet);
         signer,
         {
             senderAddress: AccountAddress.fromBase58(wallet.value.address),
-            energy: Energy.create(10000n),
+            energy: Energy.create(10000),
         },
         credential,
         cli.flags.data
diff --git a/examples/cis4/registerRevocationKeys.ts b/examples/cis4/registerRevocationKeys.ts
index edd934dbc..aa48d48d7 100644
--- a/examples/cis4/registerRevocationKeys.ts
+++ b/examples/cis4/registerRevocationKeys.ts
@@ -103,7 +103,7 @@ const signer = buildAccountSigner(wallet);
         signer,
         {
             senderAddress: AccountAddress.fromBase58(wallet.value.address),
-            energy: Energy.create(10000n),
+            energy: Energy.create(10000),
         },
         keys,
         cli.flags.data
diff --git a/examples/cis4/removeRevocationKeys.ts b/examples/cis4/removeRevocationKeys.ts
index 3855aa53b..036ae0235 100644
--- a/examples/cis4/removeRevocationKeys.ts
+++ b/examples/cis4/removeRevocationKeys.ts
@@ -88,7 +88,7 @@ const signer = buildAccountSigner(wallet);
         signer,
         {
             senderAddress: AccountAddress.fromBase58(wallet.value.address),
-            energy: Energy.create(10000n),
+            energy: Energy.create(10000),
         },
         cli.flags.keys,
         cli.flags.data
diff --git a/examples/cis4/revokeCredentialAsHolder.ts b/examples/cis4/revokeCredentialAsHolder.ts
index 0c778fa85..7b1c7da99 100644
--- a/examples/cis4/revokeCredentialAsHolder.ts
+++ b/examples/cis4/revokeCredentialAsHolder.ts
@@ -99,7 +99,7 @@ const signer = buildAccountSigner(wallet);
         signer,
         {
             senderAddress: AccountAddress.fromBase58(wallet.value.address),
-            energy: Energy.create(10000n),
+            energy: Energy.create(10000),
         },
         hSigner,
         nonce,
diff --git a/examples/cis4/revokeCredentialAsIssuer.ts b/examples/cis4/revokeCredentialAsIssuer.ts
index 106714e70..001b388f2 100644
--- a/examples/cis4/revokeCredentialAsIssuer.ts
+++ b/examples/cis4/revokeCredentialAsIssuer.ts
@@ -92,7 +92,7 @@ const signer = buildAccountSigner(wallet);
         signer,
         {
             senderAddress: AccountAddress.fromBase58(wallet.value.address),
-            energy: Energy.create(10000n),
+            energy: Energy.create(10000),
         },
         cli.flags.credId,
         cli.flags.reason,
diff --git a/examples/cis4/revokeCredentialAsOther.ts b/examples/cis4/revokeCredentialAsOther.ts
index add3623ef..a9854e8fc 100644
--- a/examples/cis4/revokeCredentialAsOther.ts
+++ b/examples/cis4/revokeCredentialAsOther.ts
@@ -105,7 +105,7 @@ const signer = buildAccountSigner(wallet);
         signer,
         {
             senderAddress: AccountAddress.fromBase58(wallet.value.address),
-            energy: Energy.create(10000n),
+            energy: Energy.create(10000),
         },
         rSigner,
         cli.flags.credId,
diff --git a/packages/ccd-js-gen/src/lib.ts b/packages/ccd-js-gen/src/lib.ts
index 679c294f2..cc186e778 100644
--- a/packages/ccd-js-gen/src/lib.ts
+++ b/packages/ccd-js-gen/src/lib.ts
@@ -843,12 +843,18 @@ function schemaToTypeAndMapper(
             };
         case 'U64':
         case 'I64':
+            return {
+                type: 'number | bigint',
+                mapper(id) {
+                    return `BigInt(${id})`;
+                },
+            };
         case 'U128':
         case 'I128':
             return {
                 type: 'number | bigint',
                 mapper(id) {
-                    return `BigInt(${id}).toString()`; // TODO: check that the schema JSON actually use a string here.
+                    return `BigInt(${id}).toString()`;
                 },
             };
         case 'Amount':
diff --git a/packages/common/src/accountTransactions.ts b/packages/common/src/accountTransactions.ts
index 6a6aa9219..c777e3086 100644
--- a/packages/common/src/accountTransactions.ts
+++ b/packages/common/src/accountTransactions.ts
@@ -47,7 +47,7 @@ export class SimpleTransferHandler
     }
 
     serialize(transfer: SimpleTransferPayload): Buffer {
-        const serializedToAddress = transfer.toAddress.decodedAddress;
+        const serializedToAddress = AccountAddress.toBuffer(transfer.toAddress);
         const serializedAmount = encodeWord64(transfer.amount.microCcdAmount);
         return Buffer.concat([serializedToAddress, serializedAmount]);
     }
@@ -71,7 +71,7 @@ export class SimpleTransferWithMemoHandler
     implements AccountTransactionHandler<SimpleTransferWithMemoPayload>
 {
     serialize(transfer: SimpleTransferWithMemoPayload): Buffer {
-        const serializedToAddress = transfer.toAddress.decodedAddress;
+        const serializedToAddress = AccountAddress.toBuffer(transfer.toAddress);
         const serializedMemo = encodeDataBlob(transfer.memo);
         const serializedAmount = encodeWord64(transfer.amount.microCcdAmount);
         return Buffer.concat([
diff --git a/packages/common/src/deserialization.ts b/packages/common/src/deserialization.ts
index b85ee6c01..68ad74259 100644
--- a/packages/common/src/deserialization.ts
+++ b/packages/common/src/deserialization.ts
@@ -1,4 +1,3 @@
-import { Buffer } from 'buffer/index.js';
 import { getAccountTransactionHandler } from './accountTransactions.js';
 import { Cursor } from './deserializationHelpers.js';
 import {
@@ -8,6 +7,7 @@ import {
     isAccountTransactionType,
 } from './types.js';
 import * as AccountAddress from './types/AccountAddress.js';
+import * as AccountSequenceNumber from './types/SequenceNumber.js';
 import { TransactionExpiry } from './types/transactionExpiry.js';
 
 /**
@@ -61,10 +61,10 @@ function deserializeAccountTransactionSignature(
 function deserializeTransactionHeader(
     serializedHeader: Cursor
 ): AccountTransactionHeader {
-    const sender = AccountAddress.fromBuffer(
-        Buffer.from(serializedHeader.read(32))
+    const sender = AccountAddress.fromBuffer(serializedHeader.read(32));
+    const nonce = AccountSequenceNumber.create(
+        serializedHeader.read(8).readBigUInt64BE(0)
     );
-    const nonce = serializedHeader.read(8).readBigUInt64BE(0);
     // TODO: extract payloadSize and energyAmount?
     // energyAmount
     serializedHeader.read(8).readBigUInt64BE(0);
diff --git a/packages/common/src/energyCost.ts b/packages/common/src/energyCost.ts
index 99bb4879a..2261eb0f6 100644
--- a/packages/common/src/energyCost.ts
+++ b/packages/common/src/energyCost.ts
@@ -6,6 +6,7 @@ import {
     ChainParameters,
     Ratio,
 } from './types.js';
+import * as Energy from './types/Energy.js';
 
 /**
  * These constants must be consistent with constA and constB in:
@@ -31,11 +32,11 @@ export function calculateEnergyCost(
     signatureCount: bigint,
     payloadSize: bigint,
     transactionSpecificCost: bigint
-): bigint {
-    return (
+): Energy.Type {
+    return Energy.create(
         constantA * signatureCount +
-        constantB * (accountTransactionHeaderSize + payloadSize) +
-        transactionSpecificCost
+            constantB * (accountTransactionHeaderSize + payloadSize) +
+            transactionSpecificCost
     );
 }
 
@@ -48,7 +49,7 @@ export function getEnergyCost(
     transactionType: AccountTransactionType,
     payload: AccountTransactionPayload,
     signatureCount = 1n
-): bigint {
+): Energy.Type {
     const handler = getAccountTransactionHandler(transactionType);
     const size = handler.serialize(payload).length;
     return calculateEnergyCost(
diff --git a/packages/common/src/grpc/GRPCClient.ts b/packages/common/src/grpc/GRPCClient.ts
index b1e6f4d93..811ae154a 100644
--- a/packages/common/src/grpc/GRPCClient.ts
+++ b/packages/common/src/grpc/GRPCClient.ts
@@ -39,6 +39,7 @@ import * as TransactionHash from '../types/TransactionHash.js';
 import * as ContractAddress from '../types/ContractAddress.js';
 import * as Parameter from '../types/Parameter.js';
 import * as Energy from '../types/Energy.js';
+import * as SequenceNumber from '../types/SequenceNumber.js';
 
 /**
  * @hidden
@@ -364,7 +365,7 @@ export class ConcordiumGRPCClient {
      */
     async sendRawAccountTransaction(
         header: v1.AccountTransactionHeader,
-        energyAmount: bigint,
+        energyAmount: Energy.Type,
         payload: Uint8Array,
         signature: v1.AccountTransactionSignature
     ): Promise<TransactionHash.Type> {
@@ -373,9 +374,9 @@ export class ConcordiumGRPCClient {
 
         // Put together sendBlockItemRequest
         const convertedHeader: v2.AccountTransactionHeader = {
-            sender: { value: header.sender.decodedAddress },
-            sequenceNumber: { value: header.nonce },
-            energyAmount: { value: energyAmount },
+            sender: AccountAddress.toProto(header.sender),
+            sequenceNumber: SequenceNumber.toProto(header.nonce),
+            energyAmount: Energy.toProto(energyAmount),
             expiry: { value: header.expiry.expiryEpochSeconds },
         };
         const accountTransaction: v2.AccountTransaction = {
diff --git a/packages/common/src/grpc/translation.ts b/packages/common/src/grpc/translation.ts
index 46bd3bb53..cc4828777 100644
--- a/packages/common/src/grpc/translation.ts
+++ b/packages/common/src/grpc/translation.ts
@@ -15,6 +15,7 @@ import * as ContractAddress from '../types/ContractAddress.js';
 import * as Energy from '../types/Energy.js';
 import * as Duration from '../types/Duration.js';
 import * as Timestamp from '../types/Timestamp.js';
+import * as SequenceNumber from '../types/SequenceNumber.js';
 
 function unwrapToHex(bytes: Uint8Array | undefined): v1.HexString {
     return Buffer.from(unwrap(bytes)).toString('hex');
@@ -374,7 +375,7 @@ export function accountInfo(acc: v2.AccountInfo): v1.AccountInfo {
     };
     const accInfoCommon: v1.AccountInfoSimple = {
         accountAddress: AccountAddress.fromProto(unwrap(acc.address)),
-        accountNonce: unwrap(acc.sequenceNumber?.value),
+        accountNonce: SequenceNumber.fromProto(unwrap(acc.sequenceNumber)),
         accountAmount: unwrap(acc.amount?.value),
         accountIndex: unwrap(acc.index?.value),
         accountThreshold: unwrap(acc.threshold?.value),
@@ -403,7 +404,7 @@ export function nextAccountSequenceNumber(
     nasn: v2.NextAccountSequenceNumber
 ): v1.NextAccountNonce {
     return {
-        nonce: unwrap(nasn.sequenceNumber?.value),
+        nonce: SequenceNumber.fromProto(unwrap(nasn.sequenceNumber)),
         allFinal: nasn.allFinal,
     };
 }
@@ -2226,8 +2227,8 @@ export function invokeInstanceResponse(
         case 'failure':
             return {
                 tag: 'failure',
-                usedEnergy: unwrap(
-                    invokeResponse.result.failure.usedEnergy?.value
+                usedEnergy: Energy.fromProto(
+                    unwrap(invokeResponse.result.failure.usedEnergy)
                 ),
                 reason: trRejectReason(invokeResponse.result.failure.reason),
             };
@@ -2235,7 +2236,7 @@ export function invokeInstanceResponse(
             const result = invokeResponse.result.success;
             return {
                 tag: 'success',
-                usedEnergy: unwrap(result.usedEnergy?.value),
+                usedEnergy: Energy.fromProto(unwrap(result.usedEnergy)),
                 returnValue: result.returnValue
                     ? Buffer.from(unwrap(result.returnValue)).toString('hex')
                     : undefined,
diff --git a/packages/common/src/pub/types.ts b/packages/common/src/pub/types.ts
index e19c7a82d..04092c5ea 100644
--- a/packages/common/src/pub/types.ts
+++ b/packages/common/src/pub/types.ts
@@ -51,7 +51,7 @@ export {
 
 import * as ModuleClient from '../types/ModuleClient.js';
 import * as Parameter from '../types/Parameter.js';
-import * as AccountSequenceNumber from '../types/AccountSequenceNumber.js';
+import * as SequenceNumber from '../types/SequenceNumber.js';
 import * as Energy from '../types/Energy.js';
 import * as TransactionHash from '../types/TransactionHash.js';
 import * as BlockHash from '../types/BlockHash.js';
@@ -69,7 +69,7 @@ import * as Timestamp from '../types/Timestamp.js';
 export {
     ModuleClient,
     Parameter,
-    AccountSequenceNumber,
+    SequenceNumber,
     Energy,
     TransactionHash,
     BlockHash,
diff --git a/packages/common/src/serialization.ts b/packages/common/src/serialization.ts
index b6f9bb6e1..d2964ec51 100644
--- a/packages/common/src/serialization.ts
+++ b/packages/common/src/serialization.ts
@@ -28,6 +28,7 @@ import {
 import { calculateEnergyCost } from './energyCost.js';
 import { countSignatures } from './util.js';
 import * as AccountAddress from './types/AccountAddress.js';
+import * as Energy from './types/Energy.js';
 import { sha256 } from './hash.js';
 
 function serializeAccountTransactionType(type: AccountTransactionType): Buffer {
@@ -46,11 +47,11 @@ function serializeAccountTransactionType(type: AccountTransactionType): Buffer {
 function serializeAccountTransactionHeader(
     header: AccountTransactionHeader,
     payloadSize: number,
-    energyAmount: bigint
+    energyAmount: Energy.Type
 ) {
-    const serializedSender = header.sender.decodedAddress;
-    const serializedNonce = encodeWord64(header.nonce);
-    const serializedEnergyAmount = encodeWord64(energyAmount);
+    const serializedSender = AccountAddress.toBuffer(header.sender);
+    const serializedNonce = encodeWord64(header.nonce.value);
+    const serializedEnergyAmount = encodeWord64(energyAmount.value);
     const serializedPayloadSize = encodeWord32(payloadSize);
     const serializedExpiry = encodeWord64(header.expiry.expiryEpochSeconds);
     return Buffer.concat([
diff --git a/packages/common/src/types.ts b/packages/common/src/types.ts
index a05537651..c9f09ff48 100644
--- a/packages/common/src/types.ts
+++ b/packages/common/src/types.ts
@@ -13,6 +13,7 @@ import * as Parameter from './types/Parameter.js';
 import type * as InitName from './types/InitName.js';
 import type * as ContractName from './types/ContractName.js';
 import type * as ReceiveName from './types/ReceiveName.js';
+import type * as AccountSequenceNumber from './types/SequenceNumber.js';
 import { CcdAmount } from './types/ccdAmount.js';
 import { DataBlob } from './types/DataBlob.js';
 import { TransactionExpiry } from './types/transactionExpiry.js';
@@ -948,7 +949,7 @@ export interface CryptographicParameters {
 }
 
 export interface NextAccountNonce {
-    nonce: bigint;
+    nonce: AccountSequenceNumber.Type;
     allFinal: boolean;
 }
 
@@ -1349,7 +1350,7 @@ export type AccountCredential = Versioned<
 
 interface AccountInfoCommon {
     accountAddress: AccountAddress.Type;
-    accountNonce: bigint;
+    accountNonce: AccountSequenceNumber.Type;
     accountAmount: bigint;
     accountIndex: bigint;
 
@@ -1593,7 +1594,7 @@ export interface AccountTransactionHeader {
      * the nonce for the transaction, usually acquired by
      * getting the next account nonce from the node
      */
-    nonce: bigint;
+    nonce: AccountSequenceNumber.Type;
 
     /** expiration of the transaction */
     expiry: TransactionExpiry;
@@ -1893,14 +1894,14 @@ export function buildInvoker(
 
 export interface InvokeContractSuccessResult {
     tag: 'success';
-    usedEnergy: bigint;
+    usedEnergy: Energy.Type;
     events: ContractTraceEvent[];
     returnValue?: string;
 }
 
 export interface InvokeContractFailedResult {
     tag: 'failure';
-    usedEnergy: bigint;
+    usedEnergy: Energy.Type;
     reason: RejectReason;
 }
 
@@ -1909,7 +1910,7 @@ export interface InvokeContractFailedResult {
  */
 export interface InvokeContractFailedResultV1 {
     tag: 'failure';
-    usedEnergy: bigint;
+    usedEnergy: Energy.Type;
     reason: RejectReasonV1;
 }
 
diff --git a/packages/common/src/types/AccountSequenceNumber.ts b/packages/common/src/types/AccountSequenceNumber.ts
deleted file mode 100644
index 69e00ba20..000000000
--- a/packages/common/src/types/AccountSequenceNumber.ts
+++ /dev/null
@@ -1,27 +0,0 @@
-/** Account transaction sequence number. (Formerly refered as Nonce) */
-class AccountSequenceNumber {
-    /** Having a private field prevents similar structured objects to be considered the same type (similar to nominal typing). */
-    private __nominal = true;
-    constructor(
-        /** Internal value representing the sequence number. */
-        public readonly value: bigint
-    ) {}
-}
-
-/** Account transaction sequence number. (Formerly refered as Nonce) */
-export type Type = AccountSequenceNumber;
-
-/**
- * Construct an AccountSequenceNumber type.
- * @param {bigint | number} sequenceNumber The account sequence number.
- * @throws If `sequenceNumber` is not at least 1.
- * @returns {AccountSequenceNumber}
- */
-export function create(sequenceNumber: bigint | number): AccountSequenceNumber {
-    if (sequenceNumber < 1) {
-        throw new Error(
-            'Invalid account sequence number: Must be 1 or higher.'
-        );
-    }
-    return new AccountSequenceNumber(BigInt(sequenceNumber));
-}
diff --git a/packages/common/src/types/SequenceNumber.ts b/packages/common/src/types/SequenceNumber.ts
new file mode 100644
index 000000000..408a777fb
--- /dev/null
+++ b/packages/common/src/types/SequenceNumber.ts
@@ -0,0 +1,51 @@
+import type * as Proto from '../grpc-api/v2/concordium/types.js';
+
+/** Transaction sequence number. (Formerly refered as Nonce) */
+class SequenceNumber {
+    /** Having a private field prevents similar structured objects to be considered the same type (similar to nominal typing). */
+    private __nominal = true;
+    constructor(
+        /** Internal value representing the sequence number. */
+        public readonly value: bigint
+    ) {}
+}
+
+/** A transaction sequence number. (Formerly refered as Nonce) */
+export type Type = SequenceNumber;
+
+/**
+ * Construct an SequenceNumber type.
+ * @param {bigint | number} sequenceNumber The account sequence number.
+ * @throws If `sequenceNumber` is not at least 1.
+ * @returns {SequenceNumber}
+ */
+export function create(sequenceNumber: bigint | number): SequenceNumber {
+    if (sequenceNumber < 1) {
+        throw new Error(
+            'Invalid account sequence number: Must be 1 or higher.'
+        );
+    }
+    return new SequenceNumber(BigInt(sequenceNumber));
+}
+
+/**
+ * Convert a SequenceNumber from its protobuf encoding.
+ * @param {Proto.SequenceNumber} sequenceNumber The sequence number in protobuf.
+ * @returns {SequenceNumber} The sequence number.
+ */
+export function fromProto(
+    sequenceNumber: Proto.SequenceNumber
+): SequenceNumber {
+    return create(sequenceNumber.value);
+}
+
+/**
+ * Convert a sequence number into its protobuf encoding.
+ * @param {SequenceNumber} sequenceNumber The duration.
+ * @returns {Proto.SequenceNumber} The protobuf encoding.
+ */
+export function toProto(sequenceNumber: SequenceNumber): Proto.SequenceNumber {
+    return {
+        value: sequenceNumber.value,
+    };
+}