diff --git a/src/mint-lib/mint_api_withdraw.c b/src/mint-lib/mint_api_withdraw.c
index a7c302c75..1b13a0d9a 100644
--- a/src/mint-lib/mint_api_withdraw.c
+++ b/src/mint-lib/mint_api_withdraw.c
@@ -36,7 +36,7 @@
  */
 #define JSON_WARN(error)                                                \
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,                              \
-                "JSON parsing failed at %s:%u: %s (%s)",                \
+                "JSON parsing failed at %s:%u: %s (%s)\n",              \
                 __FILE__, __LINE__, error.text, error.source)
 
 
@@ -800,7 +800,20 @@ handle_withdraw_sign_finished (void *cls,
 
   wsh->job = NULL;
   json = NULL;
-  if (0 == wsh->eno)
+  if (CURLE_OK !=
+      curl_easy_getinfo (eh,
+                         CURLINFO_RESPONSE_CODE,
+                         &response_code))
+  {
+    /* unexpected error... */
+    GNUNET_break (0);
+    response_code = 0;
+  }
+  fprintf (stderr,
+           "Response code: %u\n",
+           (unsigned int) response_code);
+  if ( (0 == wsh->eno) &&
+       (0 != response_code) )
   {
     json = json_loadb (wsh->buf,
                        wsh->buf_size,
@@ -812,18 +825,6 @@ handle_withdraw_sign_finished (void *cls,
       response_code = 0;
     }
   }
-  if (NULL != json)
-  {
-    if (CURLE_OK !=
-        curl_easy_getinfo (eh,
-                           CURLINFO_RESPONSE_CODE,
-                           &response_code))
-    {
-      /* unexpected error... */
-      GNUNET_break (0);
-      response_code = 0;
-    }
-  }
   switch (response_code)
   {
   case 0:
@@ -1032,6 +1033,10 @@ TALER_MINT_withdraw_sign (struct TALER_MINT_Handle *mint,
                  curl_easy_setopt (eh,
                                    CURLOPT_URL,
                                    wsh->url));
+  GNUNET_assert (CURLE_OK ==
+                 curl_easy_setopt (eh,
+                                   CURLOPT_VERBOSE,
+                                   1LL));
   GNUNET_assert (CURLE_OK ==
                  curl_easy_setopt (eh,
                                    CURLOPT_POSTFIELDS,
diff --git a/src/mint-lib/test_mint_api.c b/src/mint-lib/test_mint_api.c
index 6d8e0638d..8d206970d 100644
--- a/src/mint-lib/test_mint_api.c
+++ b/src/mint-lib/test_mint_api.c
@@ -358,6 +358,7 @@ add_incoming_cb (void *cls,
   cmd->details.admin_add_incoming.aih = NULL;
   if (MHD_HTTP_OK != http_status)
   {
+    GNUNET_break (0);
     fail (is);
     return;
   }
@@ -385,12 +386,10 @@ withdraw_sign_cb (void *cls,
   struct InterpreterState *is = cls;
   struct Command *cmd = &is->commands[is->ip];
 
-  fprintf (stderr,
-           "Withdraw completed: %u\n",
-           http_status);
   cmd->details.withdraw_sign.wsh = NULL;
   if (NULL == sig)
   {
+    GNUNET_break (0);
     fail (is);
     return;
   }
diff --git a/src/mint/taler-mint-httpd_db.c b/src/mint/taler-mint-httpd_db.c
index e4e8c59ec..5afc104f5 100644
--- a/src/mint/taler-mint-httpd_db.c
+++ b/src/mint/taler-mint-httpd_db.c
@@ -411,11 +411,23 @@ TMH_DB_execute_withdraw_sign (struct MHD_Connection *connection,
       break;
     }
   }
+  if (0 == (res & 1))
+  {
+    /* did not encounter any deposit operations, how can we have a reserve? */
+    GNUNET_break (0);
+    return TMH_RESPONSE_reply_internal_db_error (connection);
+  }
+  if (0 == (res & 2))
+  {
+    /* did not encounter any withdraw operations, set to zero */
+    TALER_amount_get_zero (deposit_total.currency,
+                           &withdraw_total);
+  }
   /* All reserve balances should be non-negative */
-  GNUNET_break (GNUNET_SYSERR !=
-                TALER_amount_subtract (&balance,
-                                       &deposit_total,
-                                       &withdraw_total));
+  GNUNET_assert (GNUNET_SYSERR !=
+                 TALER_amount_subtract (&balance,
+                                        &deposit_total,
+                                        &withdraw_total));
   if (0 < TALER_amount_cmp (&amount_required,
                             &balance))
   {
diff --git a/src/mint/taler-mint-httpd_deposit.c b/src/mint/taler-mint-httpd_deposit.c
index 1d4ef26df..19ea9cb50 100644
--- a/src/mint/taler-mint-httpd_deposit.c
+++ b/src/mint/taler-mint-httpd_deposit.c
@@ -139,8 +139,8 @@ parse_and_handle_deposit_request (struct MHD_Connection *connection,
   struct TALER_MINTDB_DenominationKeyIssueInformation *dki;
   struct TMH_KS_StateHandle *ks;
   struct TMH_PARSE_FieldSpecification spec[] = {
-    TMH_PARSE_MEMBER_DENOMINATION_PUBLIC_KEY ("denom_pub", &deposit.coin.denom_pub),
-    TMH_PARSE_MEMBER_DENOMINATION_SIGNATURE ("ub_sig", &deposit.coin.denom_sig),
+    TMH_PARSE_member_denomination_public_key ("denom_pub", &deposit.coin.denom_pub),
+    TMH_PARSE_member_denomination_signature ("ub_sig", &deposit.coin.denom_sig),
     TMH_PARSE_MEMBER_FIXED ("coin_pub", &deposit.coin.coin_pub),
     TMH_PARSE_MEMBER_FIXED ("merchant_pub", &deposit.merchant_pub),
     TMH_PARSE_MEMBER_FIXED ("H_contract", &deposit.h_contract),
diff --git a/src/mint/taler-mint-httpd_parsing.c b/src/mint/taler-mint-httpd_parsing.c
index d48674d2b..413d39bc6 100644
--- a/src/mint/taler-mint-httpd_parsing.c
+++ b/src/mint/taler-mint-httpd_parsing.c
@@ -768,24 +768,20 @@ TMH_PARSE_json_data (struct MHD_Connection *connection,
       *((void**)spec[i].destination) = ptr;
       break;
     case TMH_PARSE_JNC_RET_RSA_PUBLIC_KEY:
-      ptr = NULL;
       ret = TMH_PARSE_navigate_json (connection,
                                      root,
                                      TMH_PARSE_JNC_FIELD,
                                      spec[i].field_name,
                                      TMH_PARSE_JNC_RET_RSA_PUBLIC_KEY,
-                                     &ptr);
-      spec[i].destination = ptr;
+                                     spec[i].destination);
       break;
     case TMH_PARSE_JNC_RET_RSA_SIGNATURE:
-      ptr = NULL;
       ret = TMH_PARSE_navigate_json (connection,
                                      root,
                                      TMH_PARSE_JNC_FIELD,
                                      spec[i].field_name,
                                      TMH_PARSE_JNC_RET_RSA_SIGNATURE,
-                                     &ptr);
-      spec[i].destination = ptr;
+                                     spec[i].destination);
       break;
     case TMH_PARSE_JNC_RET_AMOUNT:
       GNUNET_assert (sizeof (struct TALER_Amount) ==
@@ -857,25 +853,25 @@ TMH_PARSE_release_data (struct TMH_PARSE_FieldSpecification *spec)
       break;
     case TMH_PARSE_JNC_RET_RSA_PUBLIC_KEY:
       {
-        struct TALER_DenominationPublicKey pk;
+        struct TALER_DenominationPublicKey *pk;
 
-        pk = *(struct TALER_DenominationPublicKey *) spec[i].destination;
-        if (NULL != pk.rsa_public_key)
+        pk = spec[i].destination;
+        if (NULL != pk->rsa_public_key)
         {
-          GNUNET_CRYPTO_rsa_public_key_free (pk.rsa_public_key);
-          pk.rsa_public_key = NULL;
+          GNUNET_CRYPTO_rsa_public_key_free (pk->rsa_public_key);
+          pk->rsa_public_key = NULL;
         }
       }
       break;
     case TMH_PARSE_JNC_RET_RSA_SIGNATURE:
       {
-        struct TALER_DenominationSignature sig;
+        struct TALER_DenominationSignature *sig;
 
-        sig = *(struct TALER_DenominationSignature *) spec[i].destination;
-        if (NULL != sig.rsa_signature)
+        sig = spec[i].destination;
+        if (NULL != sig->rsa_signature)
         {
-          GNUNET_CRYPTO_rsa_signature_free (sig.rsa_signature);
-          sig.rsa_signature = NULL;
+          GNUNET_CRYPTO_rsa_signature_free (sig->rsa_signature);
+          sig->rsa_signature = NULL;
         }
       }
       break;
@@ -1084,6 +1080,40 @@ TMH_PARSE_member_time_abs (const char *field,
 }
 
 
+/**
+ * Generate line in parser specification for RSA public key.
+ *
+ * @param field name of the field
+ * @param[out] pk key to initialize
+ * @return corresponding field spec
+ */
+struct TMH_PARSE_FieldSpecification
+TMH_PARSE_member_denomination_public_key (const char *field,
+                                          struct TALER_DenominationPublicKey *pk)
+{
+  struct TMH_PARSE_FieldSpecification ret =
+    { field, pk, 0, 0, TMH_PARSE_JNC_RET_RSA_PUBLIC_KEY, 0 };
+  return ret;
+}
+
+
+/**
+ * Generate line in parser specification for RSA public key.
+ *
+ * @param field name of the field
+ * @param sig the signature to initialize
+ * @return corresponding field spec
+ */
+struct TMH_PARSE_FieldSpecification
+TMH_PARSE_member_denomination_signature (const char *field,
+                                         struct TALER_DenominationSignature *sig)
+{
+  struct TMH_PARSE_FieldSpecification ret =
+    { field, sig, 0, 0, TMH_PARSE_JNC_RET_RSA_SIGNATURE, 0 };
+  return ret;
+}
+
+
 /**
  * Generate line in parser specification for an amount.
  *
diff --git a/src/mint/taler-mint-httpd_parsing.h b/src/mint/taler-mint-httpd_parsing.h
index c6981e60e..7dcbca68d 100644
--- a/src/mint/taler-mint-httpd_parsing.h
+++ b/src/mint/taler-mint-httpd_parsing.h
@@ -277,17 +277,24 @@ TMH_PARSE_member_object (const char *field,
  * Generate line in parser specification for RSA public key.
  *
  * @param field name of the field
- * @param ptrpk address of `struct TALER_DenominationPublicKey` initialize
+ * @param[out] pk key to initialize
+ * @return corresponding field spec
  */
-#define TMH_PARSE_MEMBER_DENOMINATION_PUBLIC_KEY(field,ptrpk) { field, ptrpk, 0, 0, TMH_PARSE_JNC_RET_RSA_PUBLIC_KEY, 0 }
+struct TMH_PARSE_FieldSpecification
+TMH_PARSE_member_denomination_public_key (const char *field,
+                                          struct TALER_DenominationPublicKey *pk);
+
 
 /**
  * Generate line in parser specification for RSA public key.
  *
  * @param field name of the field
- * @param ptrsig address of `struct TALER_DenominationSignature *` initialize
+ * @param sig the signature to initialize
+ * @return corresponding field spec
  */
-#define TMH_PARSE_MEMBER_DENOMINATION_SIGNATURE(field,ptrsig) { field, ptrsig, 0, 0, TMH_PARSE_JNC_RET_RSA_SIGNATURE, 0 }
+struct TMH_PARSE_FieldSpecification
+TMH_PARSE_member_denomination_signature (const char *field,
+                                         struct TALER_DenominationSignature *sig);
 
 
 /**
diff --git a/src/mint/taler-mint-httpd_refresh.c b/src/mint/taler-mint-httpd_refresh.c
index 661376f5e..28670b98d 100644
--- a/src/mint/taler-mint-httpd_refresh.c
+++ b/src/mint/taler-mint-httpd_refresh.c
@@ -174,8 +174,8 @@ get_coin_public_info (struct MHD_Connection *connection,
   struct TALER_Amount amount;
   struct TMH_PARSE_FieldSpecification spec[] = {
     TMH_PARSE_MEMBER_FIXED ("coin_pub", &r_melt_detail->coin_info.coin_pub),
-    TMH_PARSE_MEMBER_DENOMINATION_SIGNATURE ("denom_sig", &sig.rsa_signature),
-    TMH_PARSE_MEMBER_DENOMINATION_PUBLIC_KEY ("denom_pub", &pk.rsa_public_key),
+    TMH_PARSE_member_denomination_signature ("denom_sig", &sig),
+    TMH_PARSE_member_denomination_public_key ("denom_pub", &pk),
     TMH_PARSE_MEMBER_FIXED ("confirm_sig", &melt_sig),
     TMH_PARSE_member_amount ("value_with_fee", &amount),
     TMH_PARSE_MEMBER_END
diff --git a/src/mint/taler-mint-httpd_responses.c b/src/mint/taler-mint-httpd_responses.c
index 74ecd15d1..9cacffe1b 100644
--- a/src/mint/taler-mint-httpd_responses.c
+++ b/src/mint/taler-mint-httpd_responses.c
@@ -47,10 +47,12 @@ TMH_RESPONSE_reply_json (struct MHD_Connection *connection,
   int ret;
 
   json_str = json_dumps (json, JSON_INDENT(2));
+  GNUNET_assert (NULL != json_str);
   resp = MHD_create_response_from_buffer (strlen (json_str), json_str,
                                           MHD_RESPMEM_MUST_FREE);
   if (NULL == resp)
   {
+    free (json_str);
     GNUNET_break (0);
     return MHD_NO;
   }
@@ -84,12 +86,17 @@ TMH_RESPONSE_reply_json_pack (struct MHD_Connection *connection,
   json_t *json;
   va_list argp;
   int ret;
+  json_error_t jerror;
 
   va_start (argp, fmt);
-  json = json_vpack_ex (NULL, 0, fmt, argp);
+  json = json_vpack_ex (&jerror, 0, fmt, argp);
   va_end (argp);
   if (NULL == json)
   {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to pack JSON with format `%s': %s\n",
+                fmt,
+                jerror.text);
     GNUNET_break (0);
     return MHD_NO;
   }
@@ -229,10 +236,10 @@ TMH_RESPONSE_reply_external_error (struct MHD_Connection *connection,
                                    const char *hint)
 {
   return TMH_RESPONSE_reply_json_pack (connection,
-                                     MHD_HTTP_BAD_REQUEST,
-                                     "{s:s, s:s}",
-                                     "error", "client error",
-                                     "hint", hint);
+                                       MHD_HTTP_BAD_REQUEST,
+                                       "{s:s, s:s}",
+                                       "error", "client error",
+                                       "hint", hint);
 }
 
 
@@ -247,9 +254,9 @@ int
 TMH_RESPONSE_reply_commit_error (struct MHD_Connection *connection)
 {
   return TMH_RESPONSE_reply_json_pack (connection,
-                                     MHD_HTTP_BAD_REQUEST,
-                                     "{s:s}",
-                                     "error", "commit failure");
+                                       MHD_HTTP_BAD_REQUEST,
+                                       "{s:s}",
+                                       "error", "commit failure");
 }
 
 
@@ -571,16 +578,14 @@ compile_reserve_history (const struct TALER_MINTDB_ReserveHistory *rh,
                                         "type", "WITHDRAW",
                                         "signature", transaction,
                                         "amount", TALER_json_from_amount (&value)));
-
       break;
     }
   }
   if (0 == ret)
   {
-    /* history is empty!? */
-    GNUNET_break (0);
-    json_decref (json_history);
-    return NULL;
+    /* did not encounter any withdraw operations, set to zero */
+    TALER_amount_get_zero (deposit_total.currency,
+                           &withdraw_total);
   }
   if (GNUNET_SYSERR ==
       TALER_amount_subtract (balance,
@@ -591,6 +596,7 @@ compile_reserve_history (const struct TALER_MINTDB_ReserveHistory *rh,
     json_decref (json_history);
     return NULL;
   }
+
   return json_history;
 }
 
@@ -609,7 +615,6 @@ TMH_RESPONSE_reply_withdraw_status_success (struct MHD_Connection *connection,
   json_t *json_balance;
   json_t *json_history;
   struct TALER_Amount balance;
-  int ret;
 
   json_history = compile_reserve_history (rh,
                                           &balance);
@@ -617,14 +622,11 @@ TMH_RESPONSE_reply_withdraw_status_success (struct MHD_Connection *connection,
     return TMH_RESPONSE_reply_internal_error (connection,
                                               "balance calculation failure");
   json_balance = TALER_json_from_amount (&balance);
-  ret = TMH_RESPONSE_reply_json_pack (connection,
-                                      MHD_HTTP_OK,
-                                      "{s:o, s:o}",
-                                      "balance", json_balance,
-                                      "history", json_history);
-  json_decref (json_history);
-  json_decref (json_balance);
-  return ret;
+  return TMH_RESPONSE_reply_json_pack (connection,
+                                       MHD_HTTP_OK,
+                                       "{s:o, s:o}",
+                                       "balance", json_balance,
+                                       "history", json_history);
 }
 
 
@@ -644,7 +646,6 @@ TMH_RESPONSE_reply_withdraw_sign_insufficient_funds (struct MHD_Connection *conn
   json_t *json_balance;
   json_t *json_history;
   struct TALER_Amount balance;
-  int ret;
 
   json_history = compile_reserve_history (rh,
                                           &balance);
@@ -652,15 +653,12 @@ TMH_RESPONSE_reply_withdraw_sign_insufficient_funds (struct MHD_Connection *conn
     return TMH_RESPONSE_reply_internal_error (connection,
                                               "balance calculation failure");
   json_balance = TALER_json_from_amount (&balance);
-  ret = TMH_RESPONSE_reply_json_pack (connection,
-                                      MHD_HTTP_FORBIDDEN,
-                                      "{s:s, s:o, s:o}",
-                                      "error", "Insufficient funds"
-                                      "balance", json_balance,
-                                      "history", json_history);
-  json_decref (json_history);
-  json_decref (json_balance);
-  return ret;
+  return TMH_RESPONSE_reply_json_pack (connection,
+                                       MHD_HTTP_FORBIDDEN,
+                                       "{s:s, s:o, s:o}",
+                                       "error", "Insufficient funds",
+                                       "balance", json_balance,
+                                       "history", json_history);
 }
 
 
@@ -676,15 +674,12 @@ TMH_RESPONSE_reply_withdraw_sign_success (struct MHD_Connection *connection,
                                           const struct TALER_MINTDB_CollectableBlindcoin *collectable)
 {
   json_t *sig_json;
-  int ret;
 
   sig_json = TALER_json_from_rsa_signature (collectable->sig.rsa_signature);
-  ret = TMH_RESPONSE_reply_json_pack (connection,
-                                      MHD_HTTP_OK,
-                                      "{s:o}",
-                                      "ev_sig", sig_json);
-  json_decref (sig_json);
-  return ret;
+  return TMH_RESPONSE_reply_json_pack (connection,
+                                       MHD_HTTP_OK,
+                                       "{s:o}",
+                                       "ev_sig", sig_json);
 }
 
 
@@ -743,7 +738,6 @@ TMH_RESPONSE_reply_refresh_melt_success (struct MHD_Connection *connection,
   struct TALER_RefreshMeltConfirmationPS body;
   struct TALER_MintSignatureP sig;
   json_t *sig_json;
-  int ret;
 
   body.purpose.size = htonl (sizeof (struct TALER_RefreshMeltConfirmationPS));
   body.purpose.purpose = htonl (TALER_SIGNATURE_MINT_CONFIRM_MELT);
@@ -754,13 +748,11 @@ TMH_RESPONSE_reply_refresh_melt_success (struct MHD_Connection *connection,
   sig_json = TALER_json_from_eddsa_sig (&body.purpose,
                                         &sig.eddsa_signature);
   GNUNET_assert (NULL != sig_json);
-  ret = TMH_RESPONSE_reply_json_pack (connection,
-                                      MHD_HTTP_OK,
-                                      "{s:i, s:o}",
-                                      "noreveal_index", (int) noreveal_index,
-                                      "signature", sig_json);
-  json_decref (sig_json);
-  return ret;
+  return TMH_RESPONSE_reply_json_pack (connection,
+                                       MHD_HTTP_OK,
+                                       "{s:i, s:o}",
+                                       "noreveal_index", (int) noreveal_index,
+                                       "signature", sig_json);
 }
 
 
@@ -916,7 +908,6 @@ TMH_RESPONSE_reply_refresh_reveal_missmatch (struct MHD_Connection *connection,
     json_array_append_new (info_links,
                            info_link_k);
   }
-
   return TMH_RESPONSE_reply_json_pack (connection,
                                        MHD_HTTP_CONFLICT,
                                        "{s:s, s:i, s:i, s:o, s:o, s:o, s:o, s:s}",
diff --git a/src/mint/taler-mint-httpd_withdraw.c b/src/mint/taler-mint-httpd_withdraw.c
index ca7ec9a01..877ae8f3c 100644
--- a/src/mint/taler-mint-httpd_withdraw.c
+++ b/src/mint/taler-mint-httpd_withdraw.c
@@ -105,7 +105,7 @@ TMH_WITHDRAW_handler_withdraw_sign (struct TMH_RequestHandler *rh,
     TMH_PARSE_MEMBER_VARIABLE ("coin_ev"),
     TMH_PARSE_MEMBER_FIXED ("reserve_pub", &wsrd.reserve_pub),
     TMH_PARSE_MEMBER_FIXED ("reserve_sig", &signature),
-    TMH_PARSE_MEMBER_DENOMINATION_PUBLIC_KEY ("denom_pub", &denomination_pub),
+    TMH_PARSE_member_denomination_public_key ("denom_pub", &denomination_pub),
     TMH_PARSE_MEMBER_END
   };