diff --git a/.stainless/stainless.yml b/.stainless/stainless.yml
index 38f41cd35..dd5b88afc 100644
--- a/.stainless/stainless.yml
+++ b/.stainless/stainless.yml
@@ -202,6 +202,7 @@ resources:
           polygon_wallet_info: '#/components/schemas/PolygonWalletExternalAccountInfo'
           lightning_wallet_info: '#/components/schemas/LightningExternalAccountInfo'
           base_wallet_info: '#/components/schemas/BaseWalletExternalAccountInfo'
+          bitcoin_wallet_info: '#/components/schemas/BitcoinWalletExternalAccountInfo'
           external_account: '#/components/schemas/ExternalAccount'
           external_account_create: '#/components/schemas/ExternalAccountCreateRequest'
           external_account_info_one_of: "#/components/schemas/ExternalAccountInfoOneOf"
@@ -935,6 +936,7 @@ openapi:
           - "$.components.schemas.PlasmaWalletExternalAccountInfo.allOf[0]"
           - "$.components.schemas.PolygonWalletExternalAccountInfo.allOf[0]"
           - "$.components.schemas.BaseWalletExternalAccountInfo.allOf[0]"
+          - "$.components.schemas.BitcoinWalletExternalAccountInfo.allOf[0]"
         keys: [ "$ref" ]
 
     # ── Remove $ref to BaseQuoteSource from quote source variants ──
diff --git a/mintlify/openapi.yaml b/mintlify/openapi.yaml
index a6069a95d..c40d5b6a8 100644
--- a/mintlify/openapi.yaml
+++ b/mintlify/openapi.yaml
@@ -3660,6 +3660,21 @@ paths:
                   lockedCurrencyAmount: 10000
                   immediatelyExecute: true
                   description: Bitcoin reward payout!
+              cryptoFundingWithRefundAccount:
+                summary: On-chain crypto funding with an explicit refund destination.
+                value:
+                  source:
+                    sourceType: REALTIME_FUNDING
+                    customerId: Customer:019542f5-b3e7-1d02-0000-000000000009
+                    currency: BTC
+                    cryptoNetwork: BITCOIN
+                    refundAccountId: ExternalAccount:e85dcbd6-dced-4ec4-b756-3c3a9ea3d965
+                  destination:
+                    destinationType: ACCOUNT
+                    accountId: ExternalAccount:a12dcbd6-dced-4ec4-b756-3c3a9ea3d123
+                  lockedCurrencySide: SENDING
+                  lockedCurrencyAmount: 100000
+                  description: On-chain deposit with a whitelisted refund destination.
       responses:
         '201':
           description: |
@@ -3705,7 +3720,8 @@ paths:
               schema:
                 $ref: '#/components/schemas/Quote'
         '400':
-          description: Bad request - Missing or invalid parameters
+          description: |
+            Bad request - Missing or invalid parameters. An on-chain crypto funding source with no `source.refundAccountId` and no internal account to fall back on is rejected with `REFUND_DESTINATION_REQUIRED`.
           content:
             application/json:
               schema:
@@ -11807,6 +11823,7 @@ components:
             | STABLECOIN_PROVIDER_ACCOUNT_INVALID | The stablecoin provider account link is not usable |
             | STABLECOIN_PROVIDER_ACCOUNT_REVOKED | The stablecoin provider account link has been revoked |
             | STABLECOIN_PROVIDER_ACCOUNT_SELECTION_REQUIRED | Multiple active provider account links exist; pass `stablecoinProviderAccountId` to select one |
+            | REFUND_DESTINATION_REQUIRED | The crypto funding source has no refund destination and the customer has no internal account for that asset; pass `source.refundAccountId` |
           enum:
             - INVALID_INPUT
             - MISSING_MANDATORY_USER_INFO
@@ -11847,6 +11864,7 @@ components:
             - STABLECOIN_PROVIDER_ACCOUNT_INVALID
             - STABLECOIN_PROVIDER_ACCOUNT_REVOKED
             - STABLECOIN_PROVIDER_ACCOUNT_SELECTION_REQUIRED
+            - REFUND_DESTINATION_REQUIRED
         message:
           type: string
           description: Error message
@@ -16758,6 +16776,7 @@ components:
         - ZMW_ACCOUNT
         - SWIFT_ACCOUNT
         - BASE_WALLET
+        - BITCOIN_L1
         - ETHEREUM_WALLET
         - LIGHTNING
         - PLASMA_WALLET
@@ -18828,6 +18847,25 @@ components:
       allOf:
         - $ref: '#/components/schemas/BaseExternalAccountInfo'
         - $ref: '#/components/schemas/BaseWalletInfo'
+    BitcoinWalletInfo:
+      type: object
+      required:
+        - address
+        - accountType
+      properties:
+        accountType:
+          type: string
+          enum:
+            - BITCOIN_L1
+        address:
+          type: string
+          description: Bitcoin (L1) on-chain address
+          example: bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq
+    BitcoinWalletExternalAccountInfo:
+      title: Bitcoin L1 Wallet
+      allOf:
+        - $ref: '#/components/schemas/BaseExternalAccountInfo'
+        - $ref: '#/components/schemas/BitcoinWalletInfo'
     EthereumWalletExternalAccountInfo:
       title: Ethereum L1 Wallet
       allOf:
@@ -18977,6 +19015,7 @@ components:
         - $ref: '#/components/schemas/ZmwExternalAccountInfo'
         - $ref: '#/components/schemas/SwiftExternalAccountInfo'
         - $ref: '#/components/schemas/BaseWalletExternalAccountInfo'
+        - $ref: '#/components/schemas/BitcoinWalletExternalAccountInfo'
         - $ref: '#/components/schemas/EthereumWalletExternalAccountInfo'
         - $ref: '#/components/schemas/LightningExternalAccountInfo'
         - $ref: '#/components/schemas/PolygonWalletExternalAccountInfo'
@@ -19026,6 +19065,7 @@ components:
           ZMW_ACCOUNT: '#/components/schemas/ZmwExternalAccountInfo'
           SWIFT_ACCOUNT: '#/components/schemas/SwiftExternalAccountInfo'
           BASE_WALLET: '#/components/schemas/BaseWalletExternalAccountInfo'
+          BITCOIN_L1: '#/components/schemas/BitcoinWalletExternalAccountInfo'
           ETHEREUM_WALLET: '#/components/schemas/EthereumWalletExternalAccountInfo'
           LIGHTNING: '#/components/schemas/LightningExternalAccountInfo'
           LIGHTNING_ACCOUNT: '#/components/schemas/LightningExternalAccountInfo'
@@ -19897,6 +19937,7 @@ components:
         - $ref: '#/components/schemas/ZmwExternalAccountCreateInfo'
         - $ref: '#/components/schemas/SwiftExternalAccountCreateInfo'
         - $ref: '#/components/schemas/BaseWalletExternalAccountInfo'
+        - $ref: '#/components/schemas/BitcoinWalletExternalAccountInfo'
         - $ref: '#/components/schemas/EthereumWalletExternalAccountInfo'
         - $ref: '#/components/schemas/LightningExternalAccountInfo'
         - $ref: '#/components/schemas/PolygonWalletExternalAccountInfo'
@@ -19946,6 +19987,7 @@ components:
           ZMW_ACCOUNT: '#/components/schemas/ZmwExternalAccountCreateInfo'
           SWIFT_ACCOUNT: '#/components/schemas/SwiftExternalAccountCreateInfo'
           BASE_WALLET: '#/components/schemas/BaseWalletExternalAccountInfo'
+          BITCOIN_L1: '#/components/schemas/BitcoinWalletExternalAccountInfo'
           ETHEREUM_WALLET: '#/components/schemas/EthereumWalletExternalAccountInfo'
           LIGHTNING: '#/components/schemas/LightningExternalAccountInfo'
           POLYGON_WALLET: '#/components/schemas/PolygonWalletExternalAccountInfo'
@@ -21440,6 +21482,13 @@ components:
               type: string
               description: 'The crypto network to use for the funding source. Required when `currency` is a stablecoin (e.g. USDC, USDT). Specifies which network the customer will deposit on, so the correct deposit address can be generated. Example values: `SOLANA`, `ETHEREUM`, `BASE`, `POLYGON`, `SPARK`, `LIGHTNING`, `BITCOIN`.'
               example: SOLANA
+            refundAccountId:
+              type: string
+              description: |-
+                External account the funds are returned to if an on-chain deposit cannot be routed to complete the payment. Must be an existing external account belonging to `customerId`, with a `status` of `ACTIVE` and both a `currency` and a network matching the funding source — a USDC deposit cannot be refunded to a USDT account on the same network. Only meaningful when `currency` is a crypto asset.
+
+                If omitted, funds are returned to the customer's internal account for that asset. When the customer has no internal account to fall back on, quote creation fails with `REFUND_DESTINATION_REQUIRED` rather than accepting a deposit that cannot be returned.
+              example: ExternalAccount:e85dcbd6-dced-4ec4-b756-3c3a9ea3d965
           description: Fund the quote using a real-time funding source (RTP, SEPA Instant, Spark, Stables, etc.). This will require manual just-in-time funding using `paymentInstructions` in the response. Because quotes expire quickly, this option is only valid for instant payment methods. Do not try to fund a quote with a non-instant payment method (ACH, etc.).
     QuoteSourceOneOf:
       oneOf:
diff --git a/openapi.yaml b/openapi.yaml
index a6069a95d..c40d5b6a8 100644
--- a/openapi.yaml
+++ b/openapi.yaml
@@ -3660,6 +3660,21 @@ paths:
                   lockedCurrencyAmount: 10000
                   immediatelyExecute: true
                   description: Bitcoin reward payout!
+              cryptoFundingWithRefundAccount:
+                summary: On-chain crypto funding with an explicit refund destination.
+                value:
+                  source:
+                    sourceType: REALTIME_FUNDING
+                    customerId: Customer:019542f5-b3e7-1d02-0000-000000000009
+                    currency: BTC
+                    cryptoNetwork: BITCOIN
+                    refundAccountId: ExternalAccount:e85dcbd6-dced-4ec4-b756-3c3a9ea3d965
+                  destination:
+                    destinationType: ACCOUNT
+                    accountId: ExternalAccount:a12dcbd6-dced-4ec4-b756-3c3a9ea3d123
+                  lockedCurrencySide: SENDING
+                  lockedCurrencyAmount: 100000
+                  description: On-chain deposit with a whitelisted refund destination.
       responses:
         '201':
           description: |
@@ -3705,7 +3720,8 @@ paths:
               schema:
                 $ref: '#/components/schemas/Quote'
         '400':
-          description: Bad request - Missing or invalid parameters
+          description: |
+            Bad request - Missing or invalid parameters. An on-chain crypto funding source with no `source.refundAccountId` and no internal account to fall back on is rejected with `REFUND_DESTINATION_REQUIRED`.
           content:
             application/json:
               schema:
@@ -11807,6 +11823,7 @@ components:
             | STABLECOIN_PROVIDER_ACCOUNT_INVALID | The stablecoin provider account link is not usable |
             | STABLECOIN_PROVIDER_ACCOUNT_REVOKED | The stablecoin provider account link has been revoked |
             | STABLECOIN_PROVIDER_ACCOUNT_SELECTION_REQUIRED | Multiple active provider account links exist; pass `stablecoinProviderAccountId` to select one |
+            | REFUND_DESTINATION_REQUIRED | The crypto funding source has no refund destination and the customer has no internal account for that asset; pass `source.refundAccountId` |
           enum:
             - INVALID_INPUT
             - MISSING_MANDATORY_USER_INFO
@@ -11847,6 +11864,7 @@ components:
             - STABLECOIN_PROVIDER_ACCOUNT_INVALID
             - STABLECOIN_PROVIDER_ACCOUNT_REVOKED
             - STABLECOIN_PROVIDER_ACCOUNT_SELECTION_REQUIRED
+            - REFUND_DESTINATION_REQUIRED
         message:
           type: string
           description: Error message
@@ -16758,6 +16776,7 @@ components:
         - ZMW_ACCOUNT
         - SWIFT_ACCOUNT
         - BASE_WALLET
+        - BITCOIN_L1
         - ETHEREUM_WALLET
         - LIGHTNING
         - PLASMA_WALLET
@@ -18828,6 +18847,25 @@ components:
       allOf:
         - $ref: '#/components/schemas/BaseExternalAccountInfo'
         - $ref: '#/components/schemas/BaseWalletInfo'
+    BitcoinWalletInfo:
+      type: object
+      required:
+        - address
+        - accountType
+      properties:
+        accountType:
+          type: string
+          enum:
+            - BITCOIN_L1
+        address:
+          type: string
+          description: Bitcoin (L1) on-chain address
+          example: bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq
+    BitcoinWalletExternalAccountInfo:
+      title: Bitcoin L1 Wallet
+      allOf:
+        - $ref: '#/components/schemas/BaseExternalAccountInfo'
+        - $ref: '#/components/schemas/BitcoinWalletInfo'
     EthereumWalletExternalAccountInfo:
       title: Ethereum L1 Wallet
       allOf:
@@ -18977,6 +19015,7 @@ components:
         - $ref: '#/components/schemas/ZmwExternalAccountInfo'
         - $ref: '#/components/schemas/SwiftExternalAccountInfo'
         - $ref: '#/components/schemas/BaseWalletExternalAccountInfo'
+        - $ref: '#/components/schemas/BitcoinWalletExternalAccountInfo'
         - $ref: '#/components/schemas/EthereumWalletExternalAccountInfo'
         - $ref: '#/components/schemas/LightningExternalAccountInfo'
         - $ref: '#/components/schemas/PolygonWalletExternalAccountInfo'
@@ -19026,6 +19065,7 @@ components:
           ZMW_ACCOUNT: '#/components/schemas/ZmwExternalAccountInfo'
           SWIFT_ACCOUNT: '#/components/schemas/SwiftExternalAccountInfo'
           BASE_WALLET: '#/components/schemas/BaseWalletExternalAccountInfo'
+          BITCOIN_L1: '#/components/schemas/BitcoinWalletExternalAccountInfo'
           ETHEREUM_WALLET: '#/components/schemas/EthereumWalletExternalAccountInfo'
           LIGHTNING: '#/components/schemas/LightningExternalAccountInfo'
           LIGHTNING_ACCOUNT: '#/components/schemas/LightningExternalAccountInfo'
@@ -19897,6 +19937,7 @@ components:
         - $ref: '#/components/schemas/ZmwExternalAccountCreateInfo'
         - $ref: '#/components/schemas/SwiftExternalAccountCreateInfo'
         - $ref: '#/components/schemas/BaseWalletExternalAccountInfo'
+        - $ref: '#/components/schemas/BitcoinWalletExternalAccountInfo'
         - $ref: '#/components/schemas/EthereumWalletExternalAccountInfo'
         - $ref: '#/components/schemas/LightningExternalAccountInfo'
         - $ref: '#/components/schemas/PolygonWalletExternalAccountInfo'
@@ -19946,6 +19987,7 @@ components:
           ZMW_ACCOUNT: '#/components/schemas/ZmwExternalAccountCreateInfo'
           SWIFT_ACCOUNT: '#/components/schemas/SwiftExternalAccountCreateInfo'
           BASE_WALLET: '#/components/schemas/BaseWalletExternalAccountInfo'
+          BITCOIN_L1: '#/components/schemas/BitcoinWalletExternalAccountInfo'
           ETHEREUM_WALLET: '#/components/schemas/EthereumWalletExternalAccountInfo'
           LIGHTNING: '#/components/schemas/LightningExternalAccountInfo'
           POLYGON_WALLET: '#/components/schemas/PolygonWalletExternalAccountInfo'
@@ -21440,6 +21482,13 @@ components:
               type: string
               description: 'The crypto network to use for the funding source. Required when `currency` is a stablecoin (e.g. USDC, USDT). Specifies which network the customer will deposit on, so the correct deposit address can be generated. Example values: `SOLANA`, `ETHEREUM`, `BASE`, `POLYGON`, `SPARK`, `LIGHTNING`, `BITCOIN`.'
               example: SOLANA
+            refundAccountId:
+              type: string
+              description: |-
+                External account the funds are returned to if an on-chain deposit cannot be routed to complete the payment. Must be an existing external account belonging to `customerId`, with a `status` of `ACTIVE` and both a `currency` and a network matching the funding source — a USDC deposit cannot be refunded to a USDT account on the same network. Only meaningful when `currency` is a crypto asset.
+
+                If omitted, funds are returned to the customer's internal account for that asset. When the customer has no internal account to fall back on, quote creation fails with `REFUND_DESTINATION_REQUIRED` rather than accepting a deposit that cannot be returned.
+              example: ExternalAccount:e85dcbd6-dced-4ec4-b756-3c3a9ea3d965
           description: Fund the quote using a real-time funding source (RTP, SEPA Instant, Spark, Stables, etc.). This will require manual just-in-time funding using `paymentInstructions` in the response. Because quotes expire quickly, this option is only valid for instant payment methods. Do not try to fund a quote with a non-instant payment method (ACH, etc.).
     QuoteSourceOneOf:
       oneOf:
diff --git a/openapi/components/schemas/common/BitcoinWalletInfo.yaml b/openapi/components/schemas/common/BitcoinWalletInfo.yaml
new file mode 100644
index 000000000..5aa343cb0
--- /dev/null
+++ b/openapi/components/schemas/common/BitcoinWalletInfo.yaml
@@ -0,0 +1,13 @@
+type: object
+required:
+  - address
+  - accountType
+properties:
+  accountType:
+    type: string
+    enum:
+      - BITCOIN_L1
+  address:
+    type: string
+    description: Bitcoin (L1) on-chain address
+    example: bc1qar0srrr7xfkvy5l643lydnw9re59gtzzwf5mdq
diff --git a/openapi/components/schemas/errors/Error400.yaml b/openapi/components/schemas/errors/Error400.yaml
index 97bcaad55..c7753069f 100644
--- a/openapi/components/schemas/errors/Error400.yaml
+++ b/openapi/components/schemas/errors/Error400.yaml
@@ -53,6 +53,7 @@ properties:
       | STABLECOIN_PROVIDER_ACCOUNT_INVALID | The stablecoin provider account link is not usable |
       | STABLECOIN_PROVIDER_ACCOUNT_REVOKED | The stablecoin provider account link has been revoked |
       | STABLECOIN_PROVIDER_ACCOUNT_SELECTION_REQUIRED | Multiple active provider account links exist; pass `stablecoinProviderAccountId` to select one |
+      | REFUND_DESTINATION_REQUIRED | The crypto funding source has no refund destination and the customer has no internal account for that asset; pass `source.refundAccountId` |
     enum:
       - INVALID_INPUT
       - MISSING_MANDATORY_USER_INFO
@@ -93,6 +94,7 @@ properties:
       - STABLECOIN_PROVIDER_ACCOUNT_INVALID
       - STABLECOIN_PROVIDER_ACCOUNT_REVOKED
       - STABLECOIN_PROVIDER_ACCOUNT_SELECTION_REQUIRED
+      - REFUND_DESTINATION_REQUIRED
   message:
     type: string
     description: Error message
diff --git a/openapi/components/schemas/external_accounts/BitcoinWalletExternalAccountInfo.yaml b/openapi/components/schemas/external_accounts/BitcoinWalletExternalAccountInfo.yaml
new file mode 100644
index 000000000..d0cc3d07c
--- /dev/null
+++ b/openapi/components/schemas/external_accounts/BitcoinWalletExternalAccountInfo.yaml
@@ -0,0 +1,4 @@
+title: Bitcoin L1 Wallet
+allOf:
+  - $ref: ./BaseExternalAccountInfo.yaml
+  - $ref: ../common/BitcoinWalletInfo.yaml
diff --git a/openapi/components/schemas/external_accounts/ExternalAccountCreateInfoOneOf.yaml b/openapi/components/schemas/external_accounts/ExternalAccountCreateInfoOneOf.yaml
index 33bbac36e..082d6c8a0 100644
--- a/openapi/components/schemas/external_accounts/ExternalAccountCreateInfoOneOf.yaml
+++ b/openapi/components/schemas/external_accounts/ExternalAccountCreateInfoOneOf.yaml
@@ -38,6 +38,7 @@ oneOf:
 - $ref: ./ZmwExternalAccountCreateInfo.yaml
 - $ref: ./SwiftExternalAccountCreateInfo.yaml
 - $ref: ./BaseWalletExternalAccountInfo.yaml
+- $ref: ./BitcoinWalletExternalAccountInfo.yaml
 - $ref: ./EthereumWalletExternalAccountInfo.yaml
 - $ref: ./LightningExternalAccountInfo.yaml
 - $ref: ./PolygonWalletExternalAccountInfo.yaml
@@ -87,6 +88,7 @@ discriminator:
     ZMW_ACCOUNT: ./ZmwExternalAccountCreateInfo.yaml
     SWIFT_ACCOUNT: ./SwiftExternalAccountCreateInfo.yaml
     BASE_WALLET: ./BaseWalletExternalAccountInfo.yaml
+    BITCOIN_L1: ./BitcoinWalletExternalAccountInfo.yaml
     ETHEREUM_WALLET: ./EthereumWalletExternalAccountInfo.yaml
     LIGHTNING: ./LightningExternalAccountInfo.yaml
     POLYGON_WALLET: ./PolygonWalletExternalAccountInfo.yaml
diff --git a/openapi/components/schemas/external_accounts/ExternalAccountInfoOneOf.yaml b/openapi/components/schemas/external_accounts/ExternalAccountInfoOneOf.yaml
index 36440465f..74646f813 100644
--- a/openapi/components/schemas/external_accounts/ExternalAccountInfoOneOf.yaml
+++ b/openapi/components/schemas/external_accounts/ExternalAccountInfoOneOf.yaml
@@ -37,6 +37,7 @@ oneOf:
 - $ref: ./ZmwExternalAccountInfo.yaml
 - $ref: ./SwiftExternalAccountInfo.yaml
 - $ref: ./BaseWalletExternalAccountInfo.yaml
+- $ref: ./BitcoinWalletExternalAccountInfo.yaml
 - $ref: ./EthereumWalletExternalAccountInfo.yaml
 - $ref: ./LightningExternalAccountInfo.yaml
 - $ref: ./PolygonWalletExternalAccountInfo.yaml
@@ -86,6 +87,7 @@ discriminator:
     ZMW_ACCOUNT: ./ZmwExternalAccountInfo.yaml
     SWIFT_ACCOUNT: ./SwiftExternalAccountInfo.yaml
     BASE_WALLET: ./BaseWalletExternalAccountInfo.yaml
+    BITCOIN_L1: ./BitcoinWalletExternalAccountInfo.yaml
     ETHEREUM_WALLET: ./EthereumWalletExternalAccountInfo.yaml
     LIGHTNING: ./LightningExternalAccountInfo.yaml
     LIGHTNING_ACCOUNT: ./LightningExternalAccountInfo.yaml
diff --git a/openapi/components/schemas/external_accounts/ExternalAccountType.yaml b/openapi/components/schemas/external_accounts/ExternalAccountType.yaml
index 177800ad5..bdc8d44e7 100644
--- a/openapi/components/schemas/external_accounts/ExternalAccountType.yaml
+++ b/openapi/components/schemas/external_accounts/ExternalAccountType.yaml
@@ -38,6 +38,7 @@ enum:
 - ZMW_ACCOUNT
 - SWIFT_ACCOUNT
 - BASE_WALLET
+- BITCOIN_L1
 - ETHEREUM_WALLET
 - LIGHTNING
 - PLASMA_WALLET
diff --git a/openapi/components/schemas/quotes/RealtimeFundingQuoteSource.yaml b/openapi/components/schemas/quotes/RealtimeFundingQuoteSource.yaml
index 6793b4ac7..69b46ca3b 100644
--- a/openapi/components/schemas/quotes/RealtimeFundingQuoteSource.yaml
+++ b/openapi/components/schemas/quotes/RealtimeFundingQuoteSource.yaml
@@ -31,6 +31,21 @@ allOf:
           on, so the correct deposit address can be generated. Example values:
           `SOLANA`, `ETHEREUM`, `BASE`, `POLYGON`, `SPARK`, `LIGHTNING`, `BITCOIN`.
         example: SOLANA
+      refundAccountId:
+        type: string
+        description: >-
+          External account the funds are returned to if an on-chain deposit cannot be routed
+          to complete the payment. Must be an existing external account belonging to
+          `customerId`, with a `status` of `ACTIVE` and both a `currency` and a network
+          matching the funding source — a USDC deposit cannot be refunded to a USDT account
+          on the same network. Only meaningful when `currency` is a crypto asset.
+
+
+          If omitted, funds are returned to the customer's internal account for that asset.
+          When the customer has no internal account to fall back on, quote creation fails
+          with `REFUND_DESTINATION_REQUIRED` rather than accepting a deposit that cannot be
+          returned.
+        example: ExternalAccount:e85dcbd6-dced-4ec4-b756-3c3a9ea3d965
     description: >-
       Fund the quote using a real-time funding source (RTP, SEPA Instant, Spark, Stables, etc.).
       This will require manual just-in-time funding using `paymentInstructions` in the response.
diff --git a/openapi/paths/quotes/quotes.yaml b/openapi/paths/quotes/quotes.yaml
index 9fbfa63f2..962591441 100644
--- a/openapi/paths/quotes/quotes.yaml
+++ b/openapi/paths/quotes/quotes.yaml
@@ -79,6 +79,21 @@ post:
               lockedCurrencyAmount: 10000
               immediatelyExecute: true
               description: 'Bitcoin reward payout!'
+          cryptoFundingWithRefundAccount:
+            summary: On-chain crypto funding with an explicit refund destination.
+            value:
+              source:
+                sourceType: REALTIME_FUNDING
+                customerId: Customer:019542f5-b3e7-1d02-0000-000000000009
+                currency: BTC
+                cryptoNetwork: BITCOIN
+                refundAccountId: ExternalAccount:e85dcbd6-dced-4ec4-b756-3c3a9ea3d965
+              destination:
+                destinationType: ACCOUNT
+                accountId: ExternalAccount:a12dcbd6-dced-4ec4-b756-3c3a9ea3d123
+              lockedCurrencySide: SENDING
+              lockedCurrencyAmount: 100000
+              description: 'On-chain deposit with a whitelisted refund destination.'
   responses:
     '201':
       description: |
@@ -129,7 +144,10 @@ post:
           schema:
             $ref: ../../components/schemas/quotes/Quote.yaml
     '400':
-      description: Bad request - Missing or invalid parameters
+      description: >
+        Bad request - Missing or invalid parameters. An on-chain crypto funding source with
+        no `source.refundAccountId` and no internal account to fall back on is rejected with
+        `REFUND_DESTINATION_REQUIRED`.
       content:
         application/json:
           schema: