BitGo · OttoAllmendinger · Jan 30, 2026 · Jan 29, 2026
@@ -93,6 +93,7 @@ import { getPolicyForEnv } from './descriptor/validatePolicy';
 import { signTransaction } from './transaction/signTransaction';
 import { isUtxoWalletData, UtxoWallet } from './wallet';
 import { isDescriptorWalletData } from './descriptor/descriptorWallet';
+import type { Unspent } from './unspent';
 
 import ScriptType2Of3 = utxolib.bitgo.outputScripts.ScriptType2Of3;
 
@@ -142,8 +143,6 @@ type UtxoCustomSigningFunction<TNumber extends number | bigint> = {
 
 const { isChainCode, scriptTypeForChain, outputScripts } = bitgo;
 
-type Unspent<TNumber extends number | bigint = number> = bitgo.Unspent<TNumber>;
-
 /**
  * Convert ValidationError to TxIntentMismatchRecipientError with structured data
  *

@@ -15,17 +15,18 @@ import { UtxoCoinName } from '../../names';
 import { ParsedTransaction } from '../../transaction/types';
 import type { TransactionExplanation } from '../../transaction/fixedScript/explainTransaction';
 import type { CrossChainRecoverySigned, CrossChainRecoveryUnsigned } from '../../recovery/crossChainRecovery';
+import type { Unspent } from '../../unspent';
 
-type UnspentJSON = bitgo.Unspent<number> & { valueString: string };
+type UnspentJSON = Unspent<number> & { valueString: string };
 type TransactionInfoJSON = TransactionInfo<number> & { unspents: UnspentJSON[] };
 type TransactionPrebuildJSON = TransactionPrebuild<number> & { txInfo: TransactionInfoJSON };
 
 function parseUnspents<TNumber extends number | bigint>(
-  unspents: UnspentJSON[] | bitgo.Unspent<TNumber>[]
-): bitgo.Unspent<bigint>[] {
-  return unspents.map((unspent: bitgo.Unspent<TNumber> | UnspentJSON): bitgo.Unspent<bigint> => {
+  unspents: UnspentJSON[] | Unspent<TNumber>[]
+): Unspent<bigint>[] {
+  return unspents.map((unspent: Unspent<TNumber> | UnspentJSON): Unspent<bigint> => {
     if (typeof unspent.value === 'bigint') {
-      return unspent as bitgo.Unspent<bigint>;
+      return unspent as Unspent<bigint>;
     }
     if ('valueString' in unspent) {
       return { ...unspent, value: BigInt(unspent.valueString) };

@@ -4,6 +4,7 @@ export * from './config';
 export * from './recovery';
 export * from './transaction/fixedScript/replayProtection';
 export * from './transaction/fixedScript/signLegacyTransaction';
+export * from './unspent';
 
 export { UtxoWallet } from './wallet';
 export * as descriptor from './descriptor';

@@ -1,9 +1,8 @@
 import { BlockchairApi, AddressInfo, TransactionIO } from '@bitgo/blockapis';
-import { bitgo } from '@bitgo/utxo-lib';
 
-import { ApiNotImplementedError } from './baseApi';
+import type { Unspent } from '../unspent';
 
-type Unspent<TNumber extends number | bigint = number> = bitgo.Unspent<TNumber>;
+import { ApiNotImplementedError } from './baseApi';
 
 /**
  * An account with bear minimum information required for recoveries.

@@ -19,6 +19,7 @@ import { generateAddressWithChainAndIndex } from '../address';
 import { encodeTransaction } from '../transaction/decode';
 import { getReplayProtectionPubkeys } from '../transaction/fixedScript/replayProtection';
 import { isTestnetCoin, UtxoCoinName } from '../names';
+import type { WalletUnspent } from '../unspent';
 
 import { forCoin, RecoveryProvider } from './RecoveryProvider';
 import { MempoolApi } from './mempoolApi';
@@ -28,8 +29,7 @@ import { createBackupKeyRecoveryPsbt, getRecoveryAmount, PsbtBackend, toPsbtToUt
 type ScriptType2Of3 = utxolib.bitgo.outputScripts.ScriptType2Of3;
 type ChainCode = utxolib.bitgo.ChainCode;
 type RootWalletKeys = utxolib.bitgo.RootWalletKeys;
-type WalletUnspent<TNumber extends number | bigint> = utxolib.bitgo.WalletUnspent<TNumber>;
-type WalletUnspentJSON = utxolib.bitgo.WalletUnspent & {
+type WalletUnspentJSON = WalletUnspent & {
   valueString: string;
 };
 

@@ -11,6 +11,7 @@ import { getNetworkFromCoinName, isTestnetCoin, UtxoCoinName } from '../names';
 import { encodeTransaction } from '../transaction/decode';
 import { getReplayProtectionPubkeys } from '../transaction/fixedScript/replayProtection';
 import { toTNumber } from '../tnumber';
+import type { Unspent, WalletUnspent } from '../unspent';
 
 import {
   PsbtBackend,
@@ -22,8 +23,6 @@ import {
 
 const { unspentSum } = utxolib.bitgo;
 type RootWalletKeys = utxolib.bitgo.RootWalletKeys;
-type Unspent<TNumber extends number | bigint = number> = utxolib.bitgo.Unspent<TNumber>;
-type WalletUnspent<TNumber extends number | bigint = number> = utxolib.bitgo.WalletUnspent<TNumber>;
 
 export interface BuildRecoveryTransactionOptions {
   wallet: string;

@@ -3,9 +3,9 @@ import { Dimensions } from '@bitgo/unspents';
 import { CoinName, fixedScriptWallet, utxolibCompat, address as wasmAddress } from '@bitgo/wasm-utxo';
 
 import { getNetworkFromCoinName, UtxoCoinName } from '../names';
+import type { WalletUnspent } from '../unspent';
 
 type RootWalletKeys = utxolib.bitgo.RootWalletKeys;
-type WalletUnspent<TNumber extends number | bigint> = utxolib.bitgo.WalletUnspent<TNumber>;
 
 const { chainCodesP2tr, chainCodesP2trMusig2 } = utxolib.bitgo;
 

@@ -6,6 +6,7 @@ import { getDescriptorMapFromWallet, isDescriptorWallet } from '../descriptor';
 import { toBip32Triple } from '../keychains';
 import { getPolicyForEnv } from '../descriptor/validatePolicy';
 import { UtxoCoinName } from '../names';
+import type { Unspent } from '../unspent';
 
 import { getReplayProtectionPubkeys } from './fixedScript/replayProtection';
 import type {
@@ -25,7 +26,7 @@ export function explainTx<TNumber extends number | bigint>(
   params: {
     wallet?: IWallet;
     pubs?: string[];
-    txInfo?: { unspents?: utxolib.bitgo.Unspent<TNumber>[] };
+    txInfo?: { unspents?: Unspent<TNumber>[] };
     changeInfo?: fixedScript.ChangeAddressInfo[];
   },
   coinName: UtxoCoinName

@@ -1,9 +1,7 @@
-import * as utxolib from '@bitgo/utxo-lib';
+import type { Unspent } from '../../unspent';
 
 import type { PsbtParsedScriptType } from './signPsbtUtxolib';
 
-type Unspent<TNumber extends number | bigint = number> = utxolib.bitgo.Unspent<TNumber>;
-
 export class InputSigningError<TNumber extends number | bigint = number> extends Error {
   static expectedWalletUnspent<TNumber extends number | bigint>(
     inputIndex: number,

@@ -7,6 +7,7 @@ import * as utxocore from '@bitgo/utxo-core';
 
 import type { Bip322Message } from '../../abstractUtxoCoin';
 import type { Output, FixedScriptWalletOutput } from '../types';
+import type { Unspent } from '../../unspent';
 import { toExtendedAddressFormat } from '../recipient';
 import { getPayGoVerificationPubkey } from '../getPayGoVerificationPubkey';
 import { toBip32Triple } from '../../keychains';
@@ -192,7 +193,7 @@ function getPsbtInputSignaturesCount(
 function getTxInputSignaturesCount<TNumber extends number | bigint>(
   tx: bitgo.UtxoTransaction<TNumber>,
   params: {
-    txInfo?: { unspents?: bitgo.Unspent<TNumber>[] };
+    txInfo?: { unspents?: Unspent<TNumber>[] };
     pubs?: bitgo.RootWalletKeys | string[];
   },
   coinName: UtxoCoinName
@@ -444,7 +445,7 @@ export function explainLegacyTx<TNumber extends number | bigint>(
   tx: bitgo.UtxoTransaction<TNumber>,
   params: {
     pubs?: string[];
-    txInfo?: { unspents?: bitgo.Unspent<TNumber>[] };
+    txInfo?: { unspents?: Unspent<TNumber>[] };
     changeInfo?: { address: string; chain: number; index: number }[];
   },
   coinName: UtxoCoinName

@@ -7,6 +7,7 @@ import { isTriple, Triple } from '@bitgo/sdk-core';
 import debugLib from 'debug';
 
 import { UtxoCoinName } from '../../names';
+import type { Unspent, WalletUnspent } from '../../unspent';
 
 import { getReplayProtectionAddresses } from './replayProtection';
 import { InputSigningError, TransactionSigningError } from './SigningError';
@@ -15,8 +16,6 @@ const debug = debugLib('bitgo:v2:utxo');
 
 const { isWalletUnspent, signInputWithUnspent, toOutput } = utxolib.bitgo;
 
-type Unspent<TNumber extends number | bigint = number> = utxolib.bitgo.Unspent<TNumber>;
-
 type RootWalletKeys = utxolib.bitgo.RootWalletKeys;
 
 /**
@@ -72,7 +71,7 @@ export function signAndVerifyWalletTransaction<TNumber extends number | bigint>(
         return InputSigningError.expectedWalletUnspent<TNumber>(inputIndex, null, unspent);
       }
       try {
-        signInputWithUnspent<TNumber>(txBuilder, inputIndex, unspent, walletSigner);
+        signInputWithUnspent<TNumber>(txBuilder, inputIndex, unspent as WalletUnspent<TNumber>, walletSigner);
         debug('Successfully signed input %d of %d', inputIndex + 1, unspents.length);
       } catch (e) {
         return new InputSigningError<TNumber>(inputIndex, null, unspent, e);
@@ -96,8 +95,10 @@ export function signAndVerifyWalletTransaction<TNumber extends number | bigint>(
       if (!isWalletUnspent<TNumber>(unspent)) {
         return InputSigningError.expectedWalletUnspent<TNumber>(inputIndex, null, unspent);
       }
+      const walletUnspent = unspent as WalletUnspent<TNumber>;
       try {
-        const publicKey = walletSigner.deriveForChainAndIndex(unspent.chain, unspent.index).signer.publicKey;
+        const publicKey = walletSigner.deriveForChainAndIndex(walletUnspent.chain, walletUnspent.index).signer
+          .publicKey;
         if (
           !utxolib.bitgo.verifySignatureWithPublicKey<TNumber>(signedTransaction, inputIndex, prevOutputs, publicKey)
         ) {
@@ -124,7 +125,7 @@ export function signLegacyTransaction<TNumber extends number | bigint>(
   params: {
     isLastSignature: boolean;
     signingStep: 'signerNonce' | 'cosignerNonce' | 'signerSignature' | undefined;
-    txInfo: { unspents?: utxolib.bitgo.Unspent<TNumber>[] } | undefined;
+    txInfo: { unspents?: Unspent<TNumber>[] } | undefined;
     pubs: string[] | undefined;
     cosignerPub: string | undefined;
   }

@@ -8,6 +8,7 @@ import * as utxolib from '@bitgo/utxo-lib';
 import { fixedScriptWallet } from '@bitgo/wasm-utxo';
 
 import { UtxoCoinName } from '../../names';
+import type { Unspent } from '../../unspent';
 
 import { Musig2Participant } from './musig2';
 import { signLegacyTransaction } from './signLegacyTransaction';
@@ -60,7 +61,7 @@ export async function signTransaction<
   coinName: UtxoCoinName,
   params: {
     walletId: string | undefined;
-    txInfo: { unspents?: utxolib.bitgo.Unspent<bigint | number>[] } | undefined;
+    txInfo: { unspents?: Unspent<bigint | number>[] } | undefined;
     isLastSignature: boolean;
     signingStep: 'signerNonce' | 'cosignerNonce' | 'signerSignature' | undefined;
     /** deprecated */

@@ -0,0 +1,50 @@
+import * as utxolib from '@bitgo/utxo-lib';
+
+/**
+ * Unspent transaction output (UTXO) type definition
+ *
+ * This type represents an unspent transaction output, independent from utxo-lib.
+ * The structure matches utxolib.bitgo.Unspent but is defined locally.
+ *
+ * @property id - Format: ${txid}:${vout}. Use `parseOutputId(id)` to parse.
+ * @property address - The network-specific encoded address. Use `toOutputScript(address, network)` to obtain scriptPubKey.
+ * @property value - The amount in satoshi.
+ */
+export interface Unspent<TNumber extends number | bigint = number> {
+  /**
+   * Format: ${txid}:${vout}.
+   * Use `parseOutputId(id)` to parse.
+   */
+  id: string;
+  /**
+   * The network-specific encoded address.
+   * Use `toOutputScript(address, network)` to obtain scriptPubKey.
+   */
+  address: string;
+  /**
+   * The amount in satoshi.
+   */
+  value: TNumber;
+}
+
+/**
+ * Wallet unspent type - extends Unspent with wallet-specific fields
+ *
+ * This type includes all fields from Unspent plus:
+ * - chain: ChainCode (chain code for wallet derivation)
+ * - index: number (index for wallet derivation)
+ */
+export interface WalletUnspent<TNumber extends number | bigint = number> extends Unspent<TNumber> {
+  chain: utxolib.bitgo.ChainCode;
+  index: number;
+}
+
+/**
+ * Unspent with previous transaction data
+ *
+ * Extends Unspent with:
+ * - prevTx: Buffer (previous transaction data for legacy transactions)
+ */
+export interface UnspentWithPrevTx<TNumber extends number | bigint = number> extends Unspent<TNumber> {
+  prevTx: Buffer;
+}
@@ -18,6 +18,7 @@ import {
   FormattedOfflineVaultTxInfo,
 } from '../../../src';
 import { getCoinName } from '../../../src/names';
+import type { Unspent, WalletUnspent } from '../../../src/unspent';
 import {
   defaultBitGo,
   encryptKeychain,
@@ -35,7 +36,6 @@ import {
 import { MockRecoveryProvider } from './mock';
 
 const { toOutput } = utxolib.bitgo;
-type WalletUnspent = utxolib.bitgo.WalletUnspent<bigint>;
 type RootWalletKeys = utxolib.bitgo.RootWalletKeys;
 type ScriptType2Of3 = utxolib.bitgo.outputScripts.ScriptType2Of3;
 
@@ -148,8 +148,8 @@ function run(
       sinon.restore();
     });
 
-    let recoverUnspents: utxolib.bitgo.Unspent<bigint>[];
-    let mockedApiUnspents: utxolib.bitgo.Unspent<bigint>[];
+    let recoverUnspents: Unspent<bigint>[];
+    let mockedApiUnspents: Unspent<bigint>[];
 
     before('create recovery data', async function () {
       this.timeout(10_000);
@@ -267,7 +267,7 @@ function run(
           .map((u) => toOutput(u, coin.network))
           .map((v) => ({ ...v, value: utxolib.bitgo.toTNumber(v.value, coin.amountType) }));
         tx.ins.forEach((input, inputIndex) => {
-          const unspent = recoverUnspents[inputIndex] as WalletUnspent;
+          const unspent = recoverUnspents[inputIndex] as WalletUnspent<bigint>;
           const { publicKey } = rootKey.derivePath(walletKeys.getDerivationPath(rootKey, unspent.chain, unspent.index));
           const signatures = utxolib.bitgo
             .getSignatureVerifications(

@@ -17,6 +17,7 @@ import {
   convertLtcAddressToLegacyFormat,
 } from '../../../src';
 import { isMainnetCoin, isTestnetCoin } from '../../../src/names';
+import type { Unspent, WalletUnspent } from '../../../src/unspent';
 import {
   getFixture,
   keychainsBase58,
@@ -34,8 +35,6 @@ import { getDefaultWalletUnspentSigner } from '../util/keychains';
 
 import { MockCrossChainRecoveryProvider } from './mock';
 
-type WalletUnspent<TNumber extends number | bigint = number> = utxolib.bitgo.WalletUnspent<TNumber>;
-
 function getKeyId(k: KeychainBase58): string {
   return getSeed(k.pub).toString('hex');
 }
@@ -116,7 +115,7 @@ function run<TNumber extends number | bigint = number>(sourceCoin: AbstractUtxoC
 
     let depositTx: utxolib.bitgo.UtxoTransaction<TNumber>;
 
-    function getDepositUnspents(): utxolib.bitgo.Unspent<TNumber>[] {
+    function getDepositUnspents(): Unspent<TNumber>[] {
       return [
         mockUnspent<TNumber>(
           sourceCoin.network,

@@ -6,8 +6,7 @@ import { address as wasmAddress, AddressFormat } from '@bitgo/wasm-utxo';
 import { AbstractUtxoCoin, RecoveryProvider } from '../../../src';
 import { Bch } from '../../../src/impl/bch';
 import { Bsv } from '../../../src/impl/bsv';
-
-type Unspent<TNumber extends number | bigint = number> = bitgo.Unspent<TNumber>;
+import type { Unspent, UnspentWithPrevTx } from '../../../src/unspent';
 export class MockRecoveryProvider implements RecoveryProvider {
   public unspents: Unspent<bigint>[];
   private prevTxCache: Record<string, string> = {};
@@ -16,7 +15,7 @@ export class MockRecoveryProvider implements RecoveryProvider {
     this.unspents.forEach((u) => {
       if (utxolib.bitgo.isUnspentWithPrevTx(u)) {
         const { txid } = bitgo.parseOutputId(u.id);
-        this.prevTxCache[txid] = u.prevTx.toString('hex');
+        this.prevTxCache[txid] = (u as UnspentWithPrevTx<bigint>).prevTx.toString('hex');
       }
     });
   }

@@ -16,6 +16,7 @@ import {
 
 import { AbstractUtxoCoin, getReplayProtectionAddresses, generateAddress, getReplayProtectionPubkeys } from '../../src';
 import { SdkBackend } from '../../src/transaction/types';
+import type { Unspent, WalletUnspent } from '../../src/unspent';
 
 import {
   utxoCoins,
@@ -35,9 +36,6 @@ import {
   defaultBitGo,
 } from './util';
 
-type Unspent<TNumber extends number | bigint = number> = bitgo.Unspent<TNumber>;
-type WalletUnspent<TNumber extends number | bigint = number> = bitgo.WalletUnspent<TNumber>;
-
 function getScriptTypes2Of3() {
   return [...bitgo.outputScripts.scriptTypes2Of3, 'taprootKeyPathSpend'] as const;
 }
@@ -486,7 +484,8 @@ function run<TNumber extends number | bigint = number>(
           assert.ok(utxolib.bitgo.getPsbtInputScriptType(input), 'p2shP2pk');
           return;
         }
-        const pubkeys = walletKeys.deriveForChainAndIndex(unspent.chain, unspent.index).publicKeys;
+        const walletUnspent = unspent as WalletUnspent<bigint>;
+        const pubkeys = walletKeys.deriveForChainAndIndex(walletUnspent.chain, walletUnspent.index).publicKeys;
         pubkeys.forEach((pk, pkIndex) => {
           psbt.validateSignaturesOfInputCommon(index, pk).should.eql(signedBy.includes(walletKeys.triple[pkIndex]));
         });
@@ -546,7 +545,7 @@ function run<TNumber extends number | bigint = number>(
     async function testExplainTx(
       stageName: string,
       txHex: string,
-      unspents: utxolib.bitgo.Unspent<TNumber>[],
+      unspents: Unspent<TNumber>[],
       pubs: Triple<string> | undefined
     ): Promise<void> {
       const explanation = await coin.explainTransaction<TNumber>({