diff --git a/code/espurna/api.cpp b/code/espurna/api.cpp
index 7bf76a9f..08f60d7e 100644
--- a/code/espurna/api.cpp
+++ b/code/espurna/api.cpp
@@ -21,19 +21,8 @@ Copyright (C) 2016-2019 by Xose Pérez <xose dot perez at gmail dot com>
 #include <ESPAsyncTCP.h>
 #include <ArduinoJson.h>
 
-struct web_api_t {
-    explicit web_api_t(const String& key, api_get_callback_f getFn, api_put_callback_f putFn) :
-        key(key),
-        getFn(getFn),
-        putFn(putFn)
-    {}
-    web_api_t() = delete;
-
-    const String key;
-    api_get_callback_f getFn;
-    api_put_callback_f putFn;
-};
-std::vector<web_api_t> _apis;
+constexpr size_t ApiPathSizeMax { 64ul };
+std::vector<Api> _apis;
 
 // -----------------------------------------------------------------------------
 // API
@@ -50,16 +39,10 @@ bool _asJson(AsyncWebServerRequest *request) {
 
 void _onAPIsText(AsyncWebServerRequest *request) {
     AsyncResponseStream *response = request->beginResponseStream("text/plain");
-    String output;
-    output.reserve(48);
+    char buffer[ApiPathSizeMax] = {0};
     for (auto& api : _apis) {
-        output = "";
-        output += api.key;
-        output += " -> ";
-        output += "/api/";
-        output += api.key;
-        output += '\n';
-        response->write(output.c_str());
+        sprintf_P(buffer, PSTR("/api/%s\n"), api.path.c_str());
+        response->write(buffer);
     }
     request->send(response);
 }
@@ -69,19 +52,14 @@ constexpr size_t ApiJsonBufferSize = 1024;
 void _onAPIsJson(AsyncWebServerRequest *request) {
 
     DynamicJsonBuffer jsonBuffer(ApiJsonBufferSize);
-    JsonObject& root = jsonBuffer.createObject();
+    JsonArray& root = jsonBuffer.createArray();
 
-    constexpr const int BUFFER_SIZE = 48;
-
-    for (unsigned int i=0; i < _apis.size(); i++) {
-        char buffer[BUFFER_SIZE] = {0};
-        int res = snprintf(buffer, sizeof(buffer), "/api/%s", _apis[i].key.c_str());
-        if ((res < 0) || (res > (BUFFER_SIZE - 1))) {
-            request->send(500);
-            return;
-        }
-        root[_apis[i].key] = buffer;
+    char buffer[ApiPathSizeMax] = {0};
+    for (auto& api : _apis) {
+        sprintf(buffer, "/api/%s", api.path.c_str());
+        root.add(buffer);
     }
+
     AsyncResponseStream *response = request->beginResponseStream("application/json");
     root.printTo(*response);
     request->send(response);
@@ -129,87 +107,159 @@ void _onRPC(AsyncWebServerRequest *request) {
 
 }
 
-bool _apiRequestCallback(AsyncWebServerRequest *request) {
+struct ApiMatch {
+    Api* api { nullptr };
+    Api::Type type { Api::Type::Basic };
+};
 
-    String url = request->url();
+ApiMatch _apiMatch(const String& url, AsyncWebServerRequest* request) {
 
-    // Main API entry point
-    if (url.equals("/api") || url.equals("/apis")) {
-        _onAPIs(request);
-        return true;
+    ApiMatch result;
+    char buffer[ApiPathSizeMax] = {0};
+
+    for (auto& api : _apis) {
+        sprintf_P(buffer, PSTR("/api/%s"), api.path.c_str());
+        if (url != buffer) {
+            continue;
+        }
+
+        auto type = _asJson(request)
+            ? Api::Type::Json
+            : Api::Type::Basic;
+
+        result.api = &api;
+        result.type = type;
+        break;
     }
 
-    // Main RPC entry point
-    if (url.equals("/rpc")) {
-        _onRPC(request);
+    return result;
+}
+
+bool _apiDispatchRequest(const String& url, AsyncWebServerRequest* request) {
+
+    auto match = _apiMatch(url, request);
+    if (!match.api) {
+        return false;
+    }
+
+    if (match.type != match.api->type) {
+        DEBUG_MSG_P(PSTR("[API] Cannot handle the request type\n"));
+        request->send(404);
         return true;
     }
 
-    // Not API request
-    if (!url.startsWith("/api/")) return false;
+    const bool is_put = (
+        (!apiRestFul() || (request->method() == HTTP_PUT))
+        && request->hasParam("value", request->method() == HTTP_PUT)
+    );
 
-    for (auto& api : _apis) {
+    ApiBuffer buffer;
 
-        // Search API url for the exact match
-        if (!url.endsWith(api.key)) continue;
+    switch (match.api->type) {
 
-        // Log and check credentials
-        webLog(request);
-        if (!apiAuthenticate(request)) return false;
+    case Api::Type::Basic: {
+        if (!match.api->get.basic) {
+            break;
+        }
 
-        // Check if its a PUT
-        if (api.putFn != NULL) {
-            if (!apiRestFul() || (request->method() == HTTP_PUT)) {
-                if (request->hasParam("value", request->method() == HTTP_PUT)) {
-                    AsyncWebParameter* p = request->getParam("value", request->method() == HTTP_PUT);
-                    (api.putFn)((p->value()).c_str());
-                }
+        if (is_put) {
+            if (!match.api->put.basic) {
+                break;
             }
+            auto value = request->getParam("value", request->method() == HTTP_PUT)->value();
+            //memcpy(buffer.data, value.c_str(), value.length());
+            std::copy(value.c_str(), value.c_str() + value.length(), buffer.data);
+            match.api->get.basic(*match.api, buffer);
+            buffer.erase();
         }
 
-        // Get response from callback
-        char value[API_BUFFER_SIZE] = {0};
-        (api.getFn)(value, API_BUFFER_SIZE);
+        match.api->get.basic(*match.api, buffer);
+        request->send(200, "text/plain", buffer.data);
 
-        // The response will be a 404 NOT FOUND if the resource is not available
-        if (0 == value[0]) {
-            DEBUG_MSG_P(PSTR("[API] Sending 404 response\n"));
-            request->send(404);
-            return false;
+        return true;
+    }
+
+    // TODO: pass the body instead of `value` param
+    // TODO: handle HTTP_PUT
+    case Api::Type::Json: {
+        if (!match.api->get.json || is_put) {
+            break;
         }
 
-        DEBUG_MSG_P(PSTR("[API] Sending response '%s'\n"), value);
+        DynamicJsonBuffer jsonBuffer(API_BUFFER_SIZE);
+        JsonObject& root = jsonBuffer.createObject();
 
-        // Format response according to the Accept header
-        if (_asJson(request)) {
-            char buffer[64];
-            if (isNumber(value)) {
-                snprintf_P(buffer, sizeof(buffer), PSTR("{ \"%s\": %s }"), api.key.c_str(), value);
-            } else {
-                snprintf_P(buffer, sizeof(buffer), PSTR("{ \"%s\": \"%s\" }"), api.key.c_str(), value);
-            }
-            request->send(200, "application/json", buffer);
-        } else {
-            request->send(200, "text/plain", value);
-        }
+        match.api->get.json(*match.api, root);
+
+        AsyncResponseStream *response = request->beginResponseStream("application/json", root.measureLength() + 1);
+        root.printTo(*response);
+        request->send(response);
 
         return true;
+    }
 
     }
 
-    return false;
+    DEBUG_MSG_P(PSTR("[API] Method not supported\n"));
+    request->send(405);
+
+    return true;
+
+}
+
+bool _apiRequestCallback(AsyncWebServerRequest* request) {
+
+    String url = request->url();
+
+    if (url.equals("/rpc")) {
+        _onRPC(request);
+        return true;
+    }
+
+    if (url.equals("/api") || url.equals("/apis")) {
+        _onAPIs(request);
+        return true;
+    }
+
+    if (!url.startsWith("/api/")) return false;
+    if (!apiAuthenticate(request)) return false;
+
+    return _apiDispatchRequest(url, request);
 
 }
 
 // -----------------------------------------------------------------------------
 
-void apiRegister(const String& key, api_get_callback_f getFn, api_put_callback_f putFn) {
-    _apis.emplace_back(key, std::move(getFn), std::move(putFn));
+void apiReserve(size_t size) {
+    _apis.reserve(_apis.size() + size);
+}
+
+void apiRegister(const Api& api) {
+    if (api.path.length() >= (ApiPathSizeMax - strlen("/api/") - 1ul)) {
+        return;
+    }
+    _apis.push_back(api);
 }
 
 void apiSetup() {
     webRequestRegister(_apiRequestCallback);
 }
 
+void apiOk(const Api&, ApiBuffer& buffer) {
+    buffer.data[0] = 'O';
+    buffer.data[1] = 'K';
+    buffer.data[2] = '\0';
+}
+
+void apiError(const Api&, ApiBuffer& buffer) {
+    buffer.data[0] = '-';
+    buffer.data[1] = 'E';
+    buffer.data[2] = 'R';
+    buffer.data[3] = 'R';
+    buffer.data[4] = 'O';
+    buffer.data[5] = 'R';
+    buffer.data[6] = '\0';
+}
+
 #endif // API_SUPPORT
 
diff --git a/code/espurna/api.h b/code/espurna/api.h
index 7474b55b..4d9651ee 100644
--- a/code/espurna/api.h
+++ b/code/espurna/api.h
@@ -22,14 +22,71 @@ String apiKey();
 
 #if WEB_SUPPORT && API_SUPPORT
 
-#include <functional>
+#include <vector>
 
-using api_get_callback_f = std::function<void(char * buffer, size_t size)>;
-using api_put_callback_f = std::function<void(const char * payload)> ;
+constexpr unsigned char ApiUnusedArg = 0u;
 
-void apiRegister(const String& key, api_get_callback_f getFn, api_put_callback_f putFn = nullptr);
+struct ApiBuffer {
+    constexpr static size_t size = API_BUFFER_SIZE;
+    char data[size];
+
+    void erase() {
+        std::fill(data, data + size, '\0');
+    }
+};
+
+struct Api {
+    using BasicHandler = void(*)(const Api& api, ApiBuffer& buffer);
+    using JsonHandler = void(*)(const Api& api, JsonObject& root);
+
+    enum class Type {
+        Basic,
+        Json
+    };
+
+    Api() = delete;
+
+    Api(const String& path_, Type type_, unsigned char arg_, BasicHandler get_, BasicHandler put_ = nullptr) :
+        path(path_),
+        type(type_),
+        arg(arg_)
+    {
+        get.basic = get_;
+        put.basic = put_;
+    }
+
+    Api(const String& path_, Type type_, unsigned char arg_, JsonHandler get_, JsonHandler put_ = nullptr) :
+        path(path_),
+        type(type_),
+        arg(arg_)
+    {
+        get.json = get_;
+        put.json = put_;
+    }
+
+    String path;
+    Type type;
+    unsigned char arg;
+
+    union {
+        BasicHandler basic;
+        JsonHandler json;
+    } get;
+
+    union {
+        BasicHandler basic;
+        JsonHandler json;
+    } put;
+};
+
+void apiRegister(const Api& api);
 
 void apiCommonSetup();
 void apiSetup();
 
+void apiReserve(size_t);
+
+void apiError(const Api&, ApiBuffer& buffer);
+void apiOk(const Api&, ApiBuffer& buffer);
+
 #endif // API_SUPPORT == 1
diff --git a/code/espurna/light.cpp b/code/espurna/light.cpp
index 276ca11d..e7acddb9 100644
--- a/code/espurna/light.cpp
+++ b/code/espurna/light.cpp
@@ -853,86 +853,101 @@ void lightBroker() {
 
 #if API_SUPPORT
 
-void _lightAPISetup() {
+void _lightApiSetup() {
+
+    // Note that we expect a fixed number of entries.
+    // Otherwise, underlying vector will reserve more than we need (likely, *2 of the current size)
+    apiReserve(
+        (_light_has_color ? 4u : 0u) + 2u + _light_channels.size()
+    );
 
     if (_light_has_color) {
 
-        apiRegister(MQTT_TOPIC_COLOR_RGB,
-            [](char * buffer, size_t len) {
+        apiRegister({
+            MQTT_TOPIC_COLOR_RGB, Api::Type::Basic, ApiUnusedArg,
+            [](const Api&, ApiBuffer& buffer) {
                 if (getSetting("useCSS", 1 == LIGHT_USE_CSS)) {
-                    _toRGB(buffer, len, true);
+                    _toRGB(buffer.data, buffer.size, true);
                 } else {
-                    _toLong(buffer, len, true);
+                    _toLong(buffer.data, buffer.size, true);
                 }
             },
-            [](const char * payload) {
-                lightColor(payload, true);
+            [](const Api&, ApiBuffer& buffer) {
+                lightColor(buffer.data, true);
                 lightUpdate(true, true);
             }
-        );
+        });
 
-        apiRegister(MQTT_TOPIC_COLOR_HSV,
-            [](char * buffer, size_t len) {
-                _toHSV(buffer, len);
+        apiRegister({
+            MQTT_TOPIC_COLOR_HSV, Api::Type::Basic, ApiUnusedArg,
+            [](const Api&, ApiBuffer& buffer) {
+                _toHSV(buffer.data, buffer.size);
             },
-            [](const char * payload) {
-                lightColor(payload, false);
-                lightUpdate(true, true);
-            }
-        );
-
-        apiRegister(MQTT_TOPIC_KELVIN,
-            [](char * buffer, size_t len) {},
-            [](const char * payload) {
-                _lightAdjustKelvin(payload);
+            [](const Api&, ApiBuffer& buffer) {
+                lightColor(buffer.data, false);
                 lightUpdate(true, true);
             }
-        );
+        });
 
-        apiRegister(MQTT_TOPIC_MIRED,
-            [](char * buffer, size_t len) {},
-            [](const char * payload) {
-                _lightAdjustMireds(payload);
+        apiRegister({
+            MQTT_TOPIC_MIRED, Api::Type::Basic, ApiUnusedArg,
+            [](const Api&, ApiBuffer& buffer) {
+                sprintf(buffer.data, PSTR("%d"), _light_mireds);
+            },
+            [](const Api&, ApiBuffer& buffer) {
+                _lightAdjustMireds(buffer.data);
                 lightUpdate(true, true);
             }
-        );
-
-    }
+        });
 
-    for (unsigned int id=0; id<_light_channels.size(); id++) {
-
-        char key[15];
-        snprintf_P(key, sizeof(key), PSTR("%s/%d"), MQTT_TOPIC_CHANNEL, id);
-        apiRegister(key,
-            [id](char * buffer, size_t len) {
-                snprintf_P(buffer, len, PSTR("%d"), _light_channels[id].target);
+        apiRegister({
+            MQTT_TOPIC_KELVIN, Api::Type::Basic, ApiUnusedArg,
+            [](const Api&, ApiBuffer& buffer) {
+                sprintf(buffer.data, PSTR("%d"), _toKelvin(_light_mireds));
             },
-            [id](const char * payload) {
-                _lightAdjustChannel(id, payload);
+            [](const Api&, ApiBuffer& buffer) {
+                _lightAdjustKelvin(buffer.data);
                 lightUpdate(true, true);
             }
-        );
+        });
 
     }
 
-    apiRegister(MQTT_TOPIC_TRANSITION,
-        [](char * buffer, size_t len) {
-            snprintf_P(buffer, len, PSTR("%d"), lightTransitionTime());
+    apiRegister({
+        MQTT_TOPIC_TRANSITION, Api::Type::Basic, ApiUnusedArg,
+        [](const Api&, ApiBuffer& buffer) {
+            snprintf_P(buffer.data, buffer.size, PSTR("%u"), lightTransitionTime());
         },
-        [](const char * payload) {
-            lightTransitionTime(atol(payload));
+        [](const Api&, ApiBuffer& buffer) {
+            lightTransitionTime(atol(buffer.data));
         }
-    );
+    });
 
-    apiRegister(MQTT_TOPIC_BRIGHTNESS,
-        [](char * buffer, size_t len) {
-            snprintf_P(buffer, len, PSTR("%d"), _light_brightness);
+    apiRegister({
+        MQTT_TOPIC_BRIGHTNESS, Api::Type::Basic, ApiUnusedArg,
+        [](const Api&, ApiBuffer& buffer) {
+            snprintf_P(buffer.data, buffer.size, PSTR("%u"), _light_brightness);
         },
-        [](const char * payload) {
-            _lightAdjustBrightness(payload);
+        [](const Api&, ApiBuffer& buffer) {
+            _lightAdjustBrightness(buffer.data);
             lightUpdate(true, true);
         }
-    );
+    });
+
+    char path[32] = {0};
+    for (unsigned char id = 0; id < _light_channels.size(); ++id) {
+        snprintf_P(path, sizeof(path), PSTR(MQTT_TOPIC_CHANNEL "/%u"), id);
+        apiRegister({
+            path, Api::Type::Basic, id,
+            [](const Api& api, ApiBuffer& buffer) {
+                snprintf_P(buffer.data, buffer.size, PSTR("%u"), _light_channels[api.arg].target);
+            },
+            [](const Api& api, ApiBuffer& buffer) {
+                _lightAdjustChannel(api.arg, buffer.data);
+                lightUpdate(true, true);
+            }
+        });
+    }
 
 }
 
@@ -1421,7 +1436,7 @@ void lightSetup() {
     #endif
 
     #if API_SUPPORT
-        _lightAPISetup();
+        _lightApiSetup();
     #endif
 
     #if MQTT_SUPPORT
diff --git a/code/espurna/relay.cpp b/code/espurna/relay.cpp
index 00a4872f..7dfadf16 100644
--- a/code/espurna/relay.cpp
+++ b/code/espurna/relay.cpp
@@ -1022,60 +1022,72 @@ void relaySetupWS() {
 
 void relaySetupAPI() {
 
-    char key[20];
-
-    // API entry points (protected with apikey)
-    for (unsigned int relayID=0; relayID<relayCount(); relayID++) {
+    // Note that we expect a fixed number of entries.
+    // Otherwise, underlying vector will reserve more than we need (likely, *2 of the current size)
+    apiReserve(2u + (relayCount() * 2u));
+
+    apiRegister({
+        MQTT_TOPIC_RELAY, Api::Type::Json, ApiUnusedArg,
+        [](const Api&, JsonObject& root) {
+            JsonArray& relays = root.createNestedArray("relayStatus");
+            for (unsigned char id = 0; id < relayCount(); ++id) {
+                relays.add(_relays[id].target_status ? 1 : 0);
+            }
+        }
+    });
 
-        snprintf_P(key, sizeof(key), PSTR("%s/%d"), MQTT_TOPIC_RELAY, relayID);
-        apiRegister(key,
-            [relayID](char * buffer, size_t len) {
-				snprintf_P(buffer, len, PSTR("%d"), _relays[relayID].target_status ? 1 : 0);
+    #if defined(ITEAD_SONOFF_IFAN02)
+        apiRegister({
+            MQTT_TOPIC_SPEED, Api::Type::Basic, ApiUnusedArg,
+            [](const Api&, ApiBuffer& buffer) {
+                snprintf(buffer.data, buffer.size, "%u", getSpeed());
             },
-            [relayID](const char * payload) {
+            [](const Api&, ApiBuffer& buffer) {
+                setSpeed(atoi(buffer.data));
+                snprintf(buffer.data, buffer.size, "%u", getSpeed());
+            }
+        });
+    #endif
 
-                if (!_relayHandlePayload(relayID, payload)) {
-                    DEBUG_MSG_P(PSTR("[RELAY] Wrong payload (%s)\n"), payload);
+    char path[64] = {0};
+    for (unsigned char id = 0; id < relayCount(); ++id) {
+        sprintf_P(path, PSTR(MQTT_TOPIC_RELAY "/%u"), id);
+        apiRegister({
+            path, Api::Type::Basic, id,
+            [](const Api& api, ApiBuffer& buffer) {
+                snprintf_P(buffer.data, buffer.size, PSTR("%d"), _relays[api.arg].target_status ? 1 : 0);
+            },
+            [](const Api& api, ApiBuffer& buffer) {
+                if (!_relayHandlePayload(api.arg, buffer.data)) {
+                    DEBUG_MSG_P(PSTR("[RELAY] Invalid API payload (%s)\n"), buffer.data);
                     return;
                 }
-
             }
-        );
+        });
 
-        snprintf_P(key, sizeof(key), PSTR("%s/%d"), MQTT_TOPIC_PULSE, relayID);
-        apiRegister(key,
-            [relayID](char * buffer, size_t len) {
-                dtostrf((double) _relays[relayID].pulse_ms / 1000, 1, 3, buffer);
+        sprintf_P(path, PSTR(MQTT_TOPIC_PULSE "/%u"), id);
+        apiRegister({
+            path, Api::Type::Basic, id,
+            [](const Api& api, ApiBuffer& buffer) {
+                dtostrf((double) _relays[api.arg].pulse_ms / 1000, 1, 3, buffer.data);
             },
-            [relayID](const char * payload) {
-
-                unsigned long pulse = 1000 * atof(payload);
-                if (0 == pulse) return;
-
-                if (RELAY_PULSE_NONE != _relays[relayID].pulse) {
-                    DEBUG_MSG_P(PSTR("[RELAY] Overriding relay #%d pulse settings\n"), relayID);
+            [](const Api& api, ApiBuffer& buffer) {
+                unsigned long pulse = 1000 * atof(buffer.data);
+                if (0 == pulse) {
+                    return;
                 }
 
-                _relays[relayID].pulse_ms = pulse;
-                _relays[relayID].pulse = relayStatus(relayID) ? RELAY_PULSE_ON : RELAY_PULSE_OFF;
-                relayToggle(relayID, true, false);
-
-            }
-        );
-
-        #if defined(ITEAD_SONOFF_IFAN02)
-
-            apiRegister(MQTT_TOPIC_SPEED,
-                [relayID](char * buffer, size_t len) {
-                    snprintf(buffer, len, "%u", getSpeed());
-                },
-                [relayID](const char * payload) {
-                    setSpeed(atoi(payload));
+                if (RELAY_PULSE_NONE != _relays[api.arg].pulse) {
+                    DEBUG_MSG_P(PSTR("[RELAY] Overriding relay #%d pulse settings\n"), api.arg);
                 }
-            );
-
-        #endif
 
+                _relays[api.arg].pulse_ms = pulse;
+                _relays[api.arg].pulse = relayStatus(api.arg)
+                    ? RELAY_PULSE_ON
+                    : RELAY_PULSE_OFF;
+                relayToggle(api.arg, true, false);
+            }
+        });
     }
 
 }
diff --git a/code/espurna/rfbridge.cpp b/code/espurna/rfbridge.cpp
index f87d2690..13cd3c08 100644
--- a/code/espurna/rfbridge.cpp
+++ b/code/espurna/rfbridge.cpp
@@ -539,47 +539,60 @@ void _rfbMqttCallback(unsigned int type, const char * topic, char * payload) {
 
 #if API_SUPPORT
 
-void _rfbAPISetup() {
-
-    apiRegister(MQTT_TOPIC_RFOUT,
-        [](char * buffer, size_t len) {
-            snprintf_P(buffer, len, PSTR("OK"));
-        },
-        [](const char * payload) {
-            _rfbParseCode((char *) payload);
+void _rfbApiSetup() {
+
+    apiReserve(3u);
+
+    apiRegister({
+        MQTT_TOPIC_RFOUT, Api::Type::Basic, ApiUnusedArg,
+        apiOk, // just a stub, nothing to return
+        [](const Api&, ApiBuffer& buffer) {
+            _rfbParseCode(buffer.data);
         }
-    );
+    });
 
-    apiRegister(MQTT_TOPIC_RFLEARN,
-        [](char * buffer, size_t len) {
-            snprintf_P(buffer, len, PSTR("OK"));
-        },
-        [](const char * payload) {
+    apiRegister({
+        MQTT_TOPIC_RFLEARN, Api::Type::Basic, ApiUnusedArg,
+        apiOk, // just a stub, nothing to return
+        [](const Api&, ApiBuffer& buffer) {
             // The payload must be the relayID plus the mode (0 or 1)
-            char * tok = strtok((char *) payload, ",");
-            if (NULL == tok) return;
-            if (!isNumber(tok)) return;
-            _learnId = atoi(tok);
+            char* sep = strchr(buffer.data, ',');
+            if (NULL == sep) {
+                return;
+            }
+
+            char relay[3] {0, 0, 0};
+            if ((sep - buffer) > 2) {
+                return;
+            }
+
+            std::copy(buffer.data, sep, relay);
+            if (!isNumber(relay)) {
+                return;
+            }
+
+            _learnId = atoi(relay);
             if (_learnId >= relayCount()) {
                 DEBUG_MSG_P(PSTR("[RF] Wrong learnID (%d)\n"), _learnId);
                 return;
             }
-            tok = strtok(NULL, ",");
-            if (NULL == tok) return;
-            _learnStatus = (char) tok[0] != '0';
-            _rfbLearnImpl();
+
+            ++sep;
+            if ((*sep == '0') || (*sep == '1')) {
+                _learnStatus = (*sep != '0');
+                _rfbLearnImpl();
+            }
         }
-    );
+    });
 
-    #if !RFB_DIRECT
-        apiRegister(MQTT_TOPIC_RFRAW,
-            [](char * buffer, size_t len) {
-                snprintf_P(buffer, len, PSTR("OK"));
-            },
-            [](const char * payload) {
-                _rfbParseRaw((char *)payload);
+    #if not RFB_DIRECT
+        apiRegister({
+            MQTT_TOPIC_RFRAW, Api::Type::Basic, ApiUnusedArg,
+            apiOk, // just a stub, nothing to return
+            [](const Api&, ApiBuffer& buffer) {
+                _rfbParseRaw(buffer.data);
             }
-        );
+        });
     #endif
 
 }
@@ -723,7 +736,7 @@ void rfbSetup() {
     #endif
 
     #if API_SUPPORT
-        _rfbAPISetup();
+        _rfbApiSetup();
     #endif
 
     #if WEB_SUPPORT
diff --git a/code/espurna/sensor.cpp b/code/espurna/sensor.cpp
index 7b044769..7da76c18 100644
--- a/code/espurna/sensor.cpp
+++ b/code/espurna/sensor.cpp
@@ -1403,27 +1403,50 @@ void _sensorWebSocketOnConnected(JsonObject& root) {
 
 #if API_SUPPORT
 
-void _sensorAPISetup() {
+String _sensorApiMagnitudeName(sensor_magnitude_t& magnitude) {
+    String name = magnitudeTopic(magnitude.type);
+    if (SENSOR_USE_INDEX || (sensor_magnitude_t::counts(magnitude.type) > 1)) name = name + "/" + String(magnitude.index_global);
 
+    return name;
+}
+
+void _sensorApiJsonCallback(const Api&, JsonObject& root) {
+    JsonArray& magnitudes = root.createNestedArray("magnitudes");
     for (auto& magnitude : _magnitudes) {
+        JsonArray& data = magnitudes.createNestedArray();
+        data.add(_sensorApiMagnitudeName(magnitude));
+        data.add(magnitude.last);
+        data.add(magnitude.reported);
+    }
+}
 
-        String topic = magnitudeTopic(magnitude.type);
-        if (SENSOR_USE_INDEX || (sensor_magnitude_t::counts(magnitude.type) > 1)) topic = topic + "/" + String(magnitude.index_global);
+void _sensorApiGetValue(const Api& api, ApiBuffer& buffer) {
+    auto& magnitude = _magnitudes[api.arg];
+    double value = _sensor_realtime ? magnitude.last : magnitude.reported;
+    dtostrf(value, 1, magnitude.decimals, buffer.data);
+}
 
-        api_get_callback_f get_cb = [&magnitude](char * buffer, size_t len) {
-            double value = _sensor_realtime ? magnitude.last : magnitude.reported;
-            dtostrf(value, 1, magnitude.decimals, buffer);
-        };
-        api_put_callback_f put_cb = nullptr;
+void _sensorApiResetEnergyPutCallback(const Api& api, ApiBuffer& buffer) {
+    _sensorApiResetEnergy(_magnitudes[api.arg], buffer.data);
+}
 
-        if (magnitude.type == MAGNITUDE_ENERGY) {
-            put_cb = [&magnitude](const char* payload) {
-                _sensorApiResetEnergy(magnitude, payload);
-            };
-        }
+void _sensorApiSetup() {
 
-        apiRegister(topic.c_str(), get_cb, put_cb);
+    apiReserve(
+        _magnitudes.size() + sensor_magnitude_t::counts(MAGNITUDE_ENERGY) + 1u
+    );
+
+    apiRegister({"magnitudes", Api::Type::Json, ApiUnusedArg, _sensorApiJsonCallback});
 
+    for (unsigned char id = 0; id < _magnitudes.size(); ++id) {
+        apiRegister({
+            _sensorApiMagnitudeName(_magnitudes[id]).c_str(),
+            Api::Type::Basic, id,
+            _sensorApiGetValue,
+            (_magnitudes[id].type == MAGNITUDE_ENERGY)
+                ? _sensorApiResetEnergyPutCallback
+                : nullptr
+        });
     }
 
 }
@@ -2642,7 +2665,7 @@ void sensorSetup() {
 
     // API
     #if API_SUPPORT
-        _sensorAPISetup();
+        _sensorApiSetup();
     #endif
 
     // Terminal