diff --git a/src/api.ml b/src/api.ml
index 5c5ac87e..16675aaa 100644
--- a/src/api.ml
+++ b/src/api.ml
@@ -389,3 +389,45 @@ module AuditorTeardownMessage = struct
     |> mem "validity_end" Timestamp.jsont ~enc:validity_end
     |> finish
 end
+
+module WireFeeSetupMessage = struct
+  type t = {
+    wire_method: string;
+    (* TODO over which struct?
+       Signature using the exchange's offline key
+       with purpose TALER_SIGNATURE_MASTER_WIRE_FEES *)
+    master_sig_wire: EddsaSignature.t;
+    fee_start: Amount.t;
+    fee_end: Amount.t;
+    closing_fee: Amount.t;
+    wire_fee: Amount.t;
+  }
+
+  let jsont =
+    let make wire_method master_sig_wire fee_start fee_end closing_fee wire_fee
+        =
+      {
+        wire_method;
+        master_sig_wire;
+        fee_start;
+        fee_end;
+        closing_fee;
+        wire_fee;
+      }
+    in
+    let wire_method v = v.wire_method in
+    let master_sig_wire v = v.master_sig_wire in
+    let fee_start v = v.fee_start in
+    let fee_end v = v.fee_end in
+    let closing_fee v = v.closing_fee in
+    let wire_fee v = v.wire_fee in
+    let open Jsont.Object in
+    map ~kind:"WireFeeSetupMessage" make
+    |> mem "wire_method" Jsont.string ~enc:wire_method
+    |> mem "master_sig_wire" EddsaSignature.jsont ~enc:master_sig_wire
+    |> mem "fee_start" Amount.jsont ~enc:fee_start
+    |> mem "fee_end" Amount.jsont ~enc:fee_end
+    |> mem "closing_fee" Amount.jsont ~enc:closing_fee
+    |> mem "wire_fee" Amount.jsont ~enc:wire_fee
+    |> finish
+end