diff --git a/src/exchange-tools/taler-exchange-offline.c b/src/exchange-tools/taler-exchange-offline.c
index e7cb94b58..3d980c270 100644
--- a/src/exchange-tools/taler-exchange-offline.c
+++ b/src/exchange-tools/taler-exchange-offline.c
@@ -4255,13 +4255,17 @@ do_extensions_show (char *const *args)
 
   GNUNET_assert (NULL != exts);
   for (it = TALER_extensions_get_head ();
-       NULL != it;
+       NULL != it && NULL != it->extension;
        it = it->next)
+  {
+	  const struct TALER_Extension *extension = it->extension;
+
     GNUNET_assert (0 ==
                    json_object_set_new (exts,
                                         it->extension->name,
                                         it->extension->config_to_json (
                                           it->extension)));
+  }
   obj = GNUNET_JSON_PACK (
     GNUNET_JSON_pack_object_steal ("extensions",
                                    exts));
diff --git a/src/exchange/taler-exchange-httpd.c b/src/exchange/taler-exchange-httpd.c
index d7651d792..68fc9fb72 100644
--- a/src/exchange/taler-exchange-httpd.c
+++ b/src/exchange/taler-exchange-httpd.c
@@ -1040,6 +1040,42 @@ handle_post_auditors (struct TEH_RequestContext *rc,
                                root);
 }
 
+/**
+ * Handle GET "/extensions/..." requests.
+ *
+ * @param rc request context
+ * @param args array of additional options
+ * @return MHD result code
+ */
+static MHD_RESULT
+handle_get_extensions (struct TEH_RequestContext *rc,
+                       const char *const args[])
+{
+  const struct TALER_Extension *ext = NULL;
+
+  if (NULL == args[0])
+  {
+    GNUNET_break_op (0);
+    return r404 (rc->connection,
+                 "/extensions/$EXTENSION");
+  }
+
+  ext = TALER_extensions_get_by_name (args[0]);
+  if (NULL == ext)
+  {
+    GNUNET_break_op (0);
+    return r404 (rc->connection,
+                 "/extensions/$EXTENSION unknown");
+  }
+
+  if (NULL == ext->http_get_handler)
+    return MHD_HTTP_NOT_IMPLEMENTED;
+
+  return ext->http_get_handler (
+    rc->connection,
+    &args[1]);
+}
+
 
 /**
  * Handle POST "/extensions/..." requests.
@@ -1299,6 +1335,13 @@ handle_mhd_request (void *cls,
       .nargs_is_upper_bound = true
     },
     /* extensions endpoints */
+    {
+      .url = "extensions",
+      .method = MHD_HTTP_METHOD_GET,
+      .handler.get = &handle_get_extensions,
+      .nargs = 4, /* Arbitrary upper bound */
+      .nargs_is_upper_bound = true,
+    },
     {
       .url = "extensions",
       .method = MHD_HTTP_METHOD_POST,
diff --git a/src/exchange/taler-exchange-httpd_extensions.c b/src/exchange/taler-exchange-httpd_extensions.c
index 2a99d7a2f..2aee1b5c5 100644
--- a/src/exchange/taler-exchange-httpd_extensions.c
+++ b/src/exchange/taler-exchange-httpd_extensions.c
@@ -78,6 +78,7 @@ extension_update_event_cb (void *cls,
   }
 
   // Get the config from the database as string
+  if (extension->has_config)
   {
     char *config_str = NULL;
     enum GNUNET_DB_QueryStatus qs;
@@ -117,26 +118,26 @@ extension_update_event_cb (void *cls,
                   err.text,
                   err.source);
       GNUNET_break (0);
-      free(config_str);
+      free (config_str);
       return;
     }
 
     // Call the parser for the extension
     ret = extension->load_json_config (
       (struct TALER_Extension *) extension,
-      json_object_get(config, "config"));
+      json_object_get (config, "config"));
 
     if (GNUNET_OK != ret)
     {
       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                   "Couldn't parse configuration for extension %s from the database: %s\n",
                   extension->name,
-		  config_str);
+                  config_str);
       GNUNET_break (0);
     }
 
-    free(config_str);
-    json_decref(config);
+    free (config_str);
+    json_decref (config);
   }
 
   /* Special case age restriction: Update global flag and mask  */
@@ -190,12 +191,16 @@ TEH_extensions_init ()
        it = it->next)
   {
     const struct TALER_Extension *ext = it->extension;
+    uint32_t typ = htonl (ext->type);
     char *conf = json_dumps (ext->config_to_json (ext), JSON_COMPACT);
 
     TEH_plugin->set_extension_config (TEH_plugin->cls,
                                       ext->name,
                                       conf);
-    extension_update_event_cb (NULL, &ext->type, sizeof(ext->type));
+
+    extension_update_event_cb (NULL,
+                               &typ,
+                               sizeof(typ));
     free (conf);
   }
 
diff --git a/src/exchange/taler-exchange-httpd_keys.c b/src/exchange/taler-exchange-httpd_keys.c
index 4fb8a717f..4761f3142 100644
--- a/src/exchange/taler-exchange-httpd_keys.c
+++ b/src/exchange/taler-exchange-httpd_keys.c
@@ -1916,18 +1916,23 @@ create_krd (struct TEH_KeyStateHandle *ksh,
 
       /* flag our findings so far */
       has_extensions = true;
-      GNUNET_assert (NULL != extension->config_json);
 
       ext = GNUNET_JSON_PACK (
         GNUNET_JSON_pack_bool ("critical",
                                extension->critical),
         GNUNET_JSON_pack_string ("version",
-                                 extension->version),
-        GNUNET_JSON_pack_object_incref ("config",
-                                        extension->config_json)
+                                 extension->version)
         );
       GNUNET_assert (NULL != ext);
 
+      if (extension->has_config)
+      {
+        GNUNET_assert (extension->config_json);
+        json_object_set_new (ext,
+                             "config",
+                             extension->config_json);
+      }
+
       r = json_object_set_new (
         extensions,
         extension->name,
diff --git a/src/extensions/age_restriction/extension_age_restriction.c b/src/extensions/age_restriction/extension_age_restriction.c
index 1399fbc7a..697d066f2 100644
--- a/src/extensions/age_restriction/extension_age_restriction.c
+++ b/src/extensions/age_restriction/extension_age_restriction.c
@@ -105,8 +105,8 @@ age_restriction_load_json_config (
     json_decref (ext->config_json);
 
   ext->enabled = true;
-  ext->config_json = json_copy(jconfig);
-  json_decref(jconfig);
+  ext->config_json = json_copy (jconfig);
+  json_decref (jconfig);
 
   GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
               "loaded new age restriction config with age groups: %s\n",
@@ -155,7 +155,7 @@ age_restriction_config_to_json (
     GNUNET_JSON_pack_string ("age_groups", mask_str)
     );
 
-  free(mask_str);
+  free (mask_str);
 
   return GNUNET_JSON_PACK (
     GNUNET_JSON_pack_bool ("critical", ext->critical),
@@ -188,6 +188,7 @@ struct TALER_Extension TE_extension_age_restriction = {
   .critical = false,
   .version = "1",
   .enabled = false, /* disabled per default */
+  .has_config = true, /* we need to store configuration */
   .config = NULL,
   .config_json = NULL,
   .disable = &age_restriction_disable,
@@ -264,7 +265,7 @@ libtaler_extension_age_restriction_init (void *arg)
 
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
               "[age restriction] setting age mask to %s with #groups: %d\n",
-              TALER_age_mask_to_string(&AR_config.mask),
+              TALER_age_mask_to_string (&AR_config.mask),
               __builtin_popcount (AR_config.mask.bits) - 1);
 
   TE_extension_age_restriction.config = &AR_config;
diff --git a/src/extensions/auction_brandt/extension_auction_brandt.c b/src/extensions/auction_brandt/extension_auction_brandt.c
index a6efd94b9..a5f3af8c1 100644
--- a/src/extensions/auction_brandt/extension_auction_brandt.c
+++ b/src/extensions/auction_brandt/extension_auction_brandt.c
@@ -26,11 +26,245 @@
 #include "stdint.h"
 #include <microhttpd.h>
 
-#define EXTENSION_NAME "auction_brandt"
+#define AUCTION_BRANDT "auction_brandt"
 
 /* Path to the replay program. */
 static char *replay_program;
 
+/* This is basically BRANDT_Result with an extra string field */
+struct result
+{
+  uint16_t bidder;
+  uint16_t price_idx;
+  const char    *price;
+};
+
+/*
+ * TODO: Transcript information
+ */
+struct transcript
+{
+  // All fields from json come here.
+  uint16_t n; // #bidders + 1
+  uint16_t k; // #prices
+  uint16_t m; // type of auction
+  struct GNUNET_TIME_Absolute time_start;
+  struct GNUNET_TIME_Relative time_round;
+  bool public;
+  char **prices; // Must be of length k. We do not parse those
+  // struct msg *msgs; // Array must be of length 4*n
+
+  // struct BRANDT_Auction *auction;
+
+  struct result *results;
+  size_t results_len;
+  struct result *expected;
+  size_t expected_len;
+  uint16_t id;
+  struct GNUNET_CRYPTO_EccDlogContext *edc;
+};
+
+/**
+ * @brief returns an JSON with the error
+ */
+static enum GNUNET_GenericReturnValue
+json_error (json_t **output,
+            char *error)
+{
+  GNUNET_assert (error);
+
+  *output = json_pack ("{s:s}", "error", error);
+  GNUNET_assert (*output);
+
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "[auction_brandt] got error: %s\n",
+              error);
+
+  return GNUNET_SYSERR;
+};
+
+/**
+ * @brief returns an JSON with the result
+ */
+static enum GNUNET_GenericReturnValue
+json_result (json_t **output,
+             const struct transcript *tr)
+{
+  json_t *results;
+
+  GNUNET_assert (NULL != tr);
+
+  *output = json_object ();
+  results = json_array ();
+  GNUNET_assert (*output);
+  GNUNET_assert (results);
+
+  for (size_t i = 0; i < tr->results_len; i++)
+  {
+    json_t *result = json_pack ("{s:i, s:s}",
+                                "bidder", tr->results[i].bidder,
+                                "price", tr->results[i].price);
+    GNUNET_assert (result);
+
+    GNUNET_assert (-1 !=
+                   json_array_append_new (results, result));
+  }
+
+  GNUNET_assert (-1 !=
+                 json_object_set_new (*output,
+                                      "winners",
+                                      results));
+
+  return GNUNET_OK;
+}
+
+
+/*
+ * @brief Parses a given json as transcript.
+ *
+ * @param[in] jtr JSON input
+ * @param[out] transcript Parsed transcript data
+ * @param[out] jresult JSON output, both, for results or errors
+ * @return GNUNET_OK on succes
+ */
+static enum GNUNET_GenericReturnValue
+parse_transcript (const json_t *jtr,
+                  struct transcript *tr,
+                  json_t **output)
+{
+  // TODO: json_error_t jerror;
+  // TODO: struct GNUNET_CRYPTO_EddsaSignature sig;
+
+  GNUNET_assert (jtr);
+  GNUNET_assert (tr);
+
+  {
+    json_t *auc;
+    char *perr;
+    unsigned int eline;
+    struct GNUNET_JSON_Specification au_spec[] = {
+      GNUNET_JSON_spec_bool ("public", &tr->public),
+      GNUNET_JSON_spec_uint16 ("type", &tr->m),
+      GNUNET_JSON_spec_end ()
+    };
+
+    auc = json_object_get (jtr, "auction");
+    if (NULL == auc)
+      return json_error (output, "no auction found in transcript");
+
+    if (GNUNET_OK !=
+        GNUNET_JSON_parse (auc,
+                           au_spec,
+                           (const char **) &perr,
+                           &eline))
+      return json_error (output, perr);
+
+    // Prices...
+    {
+      json_t *prices = json_object_get (auc, "prices");
+      size_t idx;
+      json_t *val;
+
+
+      if (! json_is_array (prices))
+        // TODO: leak!?
+        return json_error (output, "no prices found");
+
+      tr->k = json_array_size (prices);
+
+      tr->prices = GNUNET_new_array (tr->k, char *);
+      json_array_foreach (prices, idx, val)
+      {
+        if (! json_is_string (val))
+          // TODO: leak!_
+          return json_error (output, "prices not strings");
+
+        tr->prices[idx] = (char *) json_string_value (val);
+
+        // TODO: parse prices
+      }
+    }
+  }
+
+  // Bidders
+  {
+    json_t *bidders;
+
+    bidders = json_object_get (jtr, "bidders");
+    if (! bidders || ! json_is_array (bidders))
+      // TODO: leak!_
+      return json_error (output, "bidders not found");
+
+    // TODO: parse bidders as pub keys;
+    tr->n = json_array_size (bidders);
+  }
+
+
+  // Messages
+  {
+    json_t *messages;
+    size_t nm;
+
+    messages = json_object_get (jtr, "transcript");
+    if (! json_is_array (messages))
+      // TODO: leak!
+      return json_error (output, "no messages found");
+
+
+    nm = json_array_size (messages);
+
+    if (nm != (4 * tr->n))
+      // TODO: leak!
+      return json_error (output, "not the right no. of messages found");
+  }
+
+  // Winners
+  {
+    json_t *winners;
+    size_t idx;
+    json_t *val;
+
+    winners = json_object_get (jtr, "winners");
+
+    if (! json_is_array (winners))
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                  "winners not provided, continuing without\n");
+      goto CONT;
+    }
+
+    tr->expected_len = json_array_size (winners);
+    tr->expected = GNUNET_new_array (tr->expected_len,
+                                     struct result);
+
+    json_array_foreach (winners, idx, val) {
+      char *error;
+
+      struct GNUNET_JSON_Specification spec[] = {
+        GNUNET_JSON_spec_uint16 ("bidder",
+                                 &(tr->expected[idx].bidder)),
+        GNUNET_JSON_spec_uint16 ("price_idx",
+                                 &(tr->expected[idx].price_idx)),
+        GNUNET_JSON_spec_string ("price",
+                                 &(tr->expected[idx].price)),
+        GNUNET_JSON_spec_end ()
+      };
+
+      if (GNUNET_OK !=
+          GNUNET_JSON_parse (val,
+                             spec,
+                             (const char**) &error,
+                             NULL))
+        // TODO: leak!
+        return json_error (output, "couldn't parse winners");
+    }
+
+CONT:
+  }
+  return json_result (output, tr);
+}
+
+
 /**
  * @brief implements the TALER_Extension.disable interface.
  *
@@ -70,7 +304,9 @@ auction_config_to_json (
   const struct TALER_Extension *ext)
 {
   /* This extension has no configuration */
-  return json_null ();
+  return GNUNET_JSON_PACK (
+    GNUNET_JSON_pack_bool ("critical", ext->critical),
+    GNUNET_JSON_pack_string ("version", ext->version));
 }
 
 
@@ -91,36 +327,68 @@ auction_load_json_config (
 }
 
 
+/**
+ * @brief implements the TALER_Extension.http_get_handler
+ */
+static MHD_RESULT
+auction_http_get_handler (
+  struct MHD_Connection *connection,
+  const char *const args[])
+{
+  /* TODO: return some meta-data about supported version, limits, etc.*/
+
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+              "auction_http_get_handler not implemented yet\n");
+
+  return TALER_MHD_reply_with_error (connection,
+                                     MHD_HTTP_NOT_IMPLEMENTED,
+                                     TALER_EC_EXCHANGE_GENERIC_OPERATION_UNKNOWN,
+                                     "auction_http_get_handler not implemented yet\n");
+
+}
+
+
 /**
  * @brief implements the TALER_Extension.http_post_handler
  */
-
 static MHD_RESULT
 auction_http_post_handler (
   struct MHD_Connection *connection,
   const json_t *root,
   const char *const args[])
 {
+  struct transcript tr = {};
+  enum GNUNET_GenericReturnValue ret;
+  json_t *result;
+
+  ret = parse_transcript (root, &tr, &result);
+
   /* TODO */
   GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-              "auction_http_post_handler not implemented yet");
-  return MHD_HTTP_NOT_IMPLEMENTED;
+              "auction_http_post_handler not implemented yet\n");
+
+  return TALER_MHD_reply_json_steal (connection,
+                                     result,
+                                     GNUNET_OK == ret? MHD_HTTP_OK :
+                                     MHD_HTTP_BAD_REQUEST);
 }
 
 
 /* The extension struct for auctions of brandt-style */
 struct TALER_Extension TE_auction_brandt = {
-  .type = 0x0815, /* TODO: where do we get this from? */
-  .name = EXTENSION_NAME,
+  .type = TALER_Extension_AuctionBrandt,
+  .name = AUCTION_BRANDT,
   .critical = false,
   .version = "0",
   .enabled = false, /* disabled per default */
+  .has_config = false, /* This extension has no configuration */
   .config = NULL,
   .config_json = NULL,
   .disable = &auction_disable,
   .test_json_config = &auction_test_json_config,
   .load_json_config = &auction_load_json_config,
   .config_to_json = &auction_config_to_json,
+  .http_get_handler = &auction_http_get_handler,
   .http_post_handler = &auction_http_post_handler,
 };
 
@@ -141,25 +409,31 @@ struct TALER_Extension TE_auction_brandt = {
  * @return Pointer to TE_auction_brandt
  */
 struct TALER_Extension *
-init (void *arg)
+libtaler_extension_auction_brandt_init (void *arg)
 {
   const struct GNUNET_CONFIGURATION_Handle *cfg = arg;
 
   if (GNUNET_SYSERR ==
       GNUNET_CONFIGURATION_get_value_string (cfg,
-                                             "extension_" EXTENSION_NAME,
-                                             "replay_program",
+                                             TALER_EXTENSION_SECTION_PREFIX
+                                             AUCTION_BRANDT,
+                                             "REPLAY_PROGRAM",
                                              &replay_program))
   {
     GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
-                               "extension_" EXTENSION_NAME,
-                               "replay_program");
+                               TALER_EXTENSION_SECTION_PREFIX AUCTION_BRANDT,
+                               "REPLAY_PROGRAM");
     return NULL;
   }
+  /* TODO: check if replay_program is actually executable */
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "[auction_brandt] loading... using replay_program '%s'\n",
+              replay_program);
 
   return &TE_auction_brandt;
 }
 
+
 /**
  * @brief Tear-down function for the extension.
  *        Will be called by GNUNET_PLUGIN_unload.
@@ -168,15 +442,14 @@ init (void *arg)
  * @return null
  */
 void *
-done (void *arg)
+libtaler_extension_auction_brandt_done (void *arg)
 {
-	auction_disable(&TE_auction_brandt);
-	GNUNET_free(replay_program);
-	replay_program=NULL;
+  auction_disable (&TE_auction_brandt);
+  GNUNET_free (replay_program);
+  replay_program = NULL;
 
-	return NULL;
+  return NULL;
 }
 
 
-
 /* end of extension_auction_brandt.c */
diff --git a/src/include/taler_extensions.h b/src/include/taler_extensions.h
index 40b14402f..1ae8ad1ed 100644
--- a/src/include/taler_extensions.h
+++ b/src/include/taler_extensions.h
@@ -31,8 +31,12 @@
 
 enum TALER_Extension_Type
 {
-  TALER_Extension_AgeRestriction = 0,
-  TALER_Extension_MaxPredefined = 1 // Must be last of the predefined
+  TALER_Extension_Refund = 0,
+  TALER_Extension_AgeRestriction = 1,
+  TALER_Extension_P2P = 2,
+  TALER_Extension_AuctionBrandt = 3,
+  TALER_Extension_Escrow = 4,
+  TALER_Extension_MaxPredefined = 5 // Must be last of the predefined
 };
 
 
@@ -59,6 +63,7 @@ struct TALER_Extension
   char *version;
   void *config;
   bool enabled;
+  bool has_config; /* some extension might not have a configuration */
   json_t *config_json;
 
   void (*disable)(struct TALER_Extension *ext);
@@ -78,6 +83,10 @@ struct TALER_Extension
     const json_t *root,
     const char *const args[]);
 
+  MHD_RESULT (*http_get_handler)(
+    struct MHD_Connection *connection,
+    const char *const args[]);
+
 };
 
 /**
diff --git a/src/lib/exchange_api_handle.c b/src/lib/exchange_api_handle.c
index add37a80f..e92e43858 100644
--- a/src/lib/exchange_api_handle.c
+++ b/src/lib/exchange_api_handle.c
@@ -931,6 +931,9 @@ decode_keys_json (const json_t *resp_obj,
 
     if (! no_extensions && ! no_signature)
     {
+	    GNUNET_log(GNUNET_ERROR_TYPE_INFO,
+			    "DEBUG: got extensions object %s\n",
+			    json_dumps(extensions, JSON_INDENT(2)));
       /* 2. We have an extensions object. Verify its signature. */
       EXITIF (GNUNET_OK !=
               TALER_extensions_verify_json_config_signature (
diff --git a/src/testing/testing_api_cmd_batch_withdraw.c b/src/testing/testing_api_cmd_batch_withdraw.c
index 3b32b5ada..a5229ae9c 100644
--- a/src/testing/testing_api_cmd_batch_withdraw.c
+++ b/src/testing/testing_api_cmd_batch_withdraw.c
@@ -490,7 +490,7 @@ TALER_TESTING_cmd_batch_withdraw (const char *label,
 
       acp = GNUNET_new (struct TALER_AgeCommitmentProof);
       hac = GNUNET_new (struct TALER_AgeCommitmentHash);
-      mask = TALER_extensions_get_age_restriction_mask();
+      mask = TALER_extensions_get_age_restriction_mask ();
       GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_WEAK,
                                   &seed,
                                   sizeof(seed));
diff --git a/src/testing/testing_api_cmd_withdraw.c b/src/testing/testing_api_cmd_withdraw.c
index 3e2f45c4b..7a81d1c33 100644
--- a/src/testing/testing_api_cmd_withdraw.c
+++ b/src/testing/testing_api_cmd_withdraw.c
@@ -590,7 +590,7 @@ TALER_TESTING_cmd_withdraw_amount (const char *label,
 
     acp = GNUNET_new (struct TALER_AgeCommitmentProof);
     hac = GNUNET_new (struct TALER_AgeCommitmentHash);
-    mask = TALER_extensions_get_age_restriction_mask();
+    mask = TALER_extensions_get_age_restriction_mask ();
     GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_WEAK,
                                 &seed,
                                 sizeof(seed));