diff --git a/src/transactions/sendBtcTransaction.ts b/src/transactions/sendBtcTransaction.ts
index a9b154a..e4e0ad8 100644
--- a/src/transactions/sendBtcTransaction.ts
+++ b/src/transactions/sendBtcTransaction.ts
@@ -2,7 +2,22 @@ import type { Json } from 'jsontokens';
 import { createUnsecuredToken } from 'jsontokens';
 
 import { getDefaultProvider } from '../provider';
-import type { SendBtcTransactionOptions } from './types';
+import type {
+  Recipient,
+  SendBtcTransactionOptions,
+  SerializedRecipient,
+  SerializedSendBtcTransactionPayload,
+} from './types';
+
+const serializer = (recipient: Recipient[]): SerializedRecipient[] => {
+  return recipient.map((value) => {
+    const { address, amountSats } = value;
+    return {
+      address,
+      amountSats: amountSats.toString(),
+    };
+  });
+};
 
 export const sendBtcTransaction = async (options: SendBtcTransactionOptions) => {
   const { getProvider = getDefaultProvider } = options;
@@ -11,16 +26,30 @@ export const sendBtcTransaction = async (options: SendBtcTransactionOptions) =>
     throw new Error('No Bitcoin wallet installed');
   }
 
-  const { recipients, senderAddress } = options.payload;
+  const { recipients, senderAddress, network, message } = options.payload;
   if (!recipients || recipients.length === 0) {
     throw new Error('At least one recipient is required');
   }
+  if (
+    recipients.some(
+      (item) => typeof item.address !== 'string' || typeof item.amountSats !== 'bigint'
+    )
+  ) {
+    throw new Error('Incorrect recipient format');
+  }
   if (!senderAddress) {
     throw new Error('The sender address is required');
   }
 
   try {
-    const request = createUnsecuredToken(options.payload as unknown as Json);
+    const serializedRecipients: SerializedRecipient[] = serializer(recipients);
+    const serializedPayload: SerializedSendBtcTransactionPayload = {
+      network,
+      senderAddress,
+      message,
+      recipients: serializedRecipients,
+    };
+    const request = createUnsecuredToken(serializedPayload as unknown as Json);
     const response = await provider.sendBtcTransaction(request);
     options.onFinish?.(response);
   } catch (error) {
diff --git a/src/transactions/types.ts b/src/transactions/types.ts
index 548e3cb..532ba6d 100644
--- a/src/transactions/types.ts
+++ b/src/transactions/types.ts
@@ -5,12 +5,20 @@ export interface Recipient {
   amountSats: bigint;
 }
 
+export type SerializedRecipient = Omit<Recipient, 'amountSats'> & {
+  amountSats: string;
+};
+
 export interface SendBtcTransactionPayload extends RequestPayload {
   recipients: Recipient[];
   senderAddress: string;
   message?: string;
 }
 
+export type SerializedSendBtcTransactionPayload = Omit<SendBtcTransactionPayload, 'recipients'> & {
+  recipients: SerializedRecipient[];
+};
+
 export type SendBtcTransactionResponse = string;
 
 export type SendBtcTransactionOptions = RequestOptions<