Updated on 2026-08-14

domain/wallet-manager/src/main/kotlin/com/tangem/domain/walletmanager/WalletManagersFacade.kt

@@ -237,6 +237,15 @@ interface WalletManagersFacade {
         derivationPath: String?,
     ): BigDecimal
 
+    /**
+     * Computes the on-chain miner fee embedded in a Bitcoin swap [psbtBase64], in satoshi.
+     *
+     * Swap providers return a "naked" PSBT whose fee is implied by `sum(inputs) - sum(outputs)`
+     * rather than reported separately. Returns `null` if the wallet manager is unavailable, the
+     * network is not a PSBT-capable Bitcoin chain, or the fee cannot be derived from the PSBT.
+     */
+    suspend fun getPsbtFee(userWalletId: UserWalletId, network: Network, psbtBase64: String): BigDecimal?
+
     /**
      * Get requirements for asset(currency)
      * @return null if there's no requirement, otherwise [AssetRequirementsCondition].