diff --git a/src/mqtt/discovery.js b/src/mqtt/discovery.js
index e7d2d30..f8cef64 100644
--- a/src/mqtt/discovery.js
+++ b/src/mqtt/discovery.js
@@ -3,6 +3,12 @@ const { getClient, getPrefix } = require('./client');
 const { allInputs, allOutputs } = require('../registry');
 const { getInputType } = require('../input-types');
 
+// Availability payload is JSON so EasyMQTT (wildcard subscriber) can parse it.
+// HA uses availability_template to extract the state field.
+const AVAIL_ONLINE  = JSON.stringify({ state: 'online' });
+const AVAIL_OFFLINE = JSON.stringify({ state: 'offline' });
+const AVAIL_TEMPLATE = '{{ value_json.state }}';
+
 function publishAll() {
   const client = getClient();
   if (!client) return;
@@ -14,11 +20,14 @@ function publishAll() {
     const availTopic = `${prefix}/${inp.moduleSlug}/availability`;
 
     const payload = {
-      name:             inp.name || inp.metric,
-      unique_id:        `myprimal_${inp.id}`,
-      state_topic:      stateTopic,
-      value_template:   '{{ value_json.value }}',
-      availability_topic: availTopic,
+      name:                  inp.name || inp.metric,
+      unique_id:             `myprimal_${inp.id}`,
+      state_topic:           stateTopic,
+      value_template:        '{{ value_json.value }}',
+      availability_topic:    availTopic,
+      availability_template: AVAIL_TEMPLATE,
+      payload_available:     'online',
+      payload_not_available: 'offline',
       device: {
         identifiers:  [`myprimal_${inp.moduleId}`],
         name:         inp.moduleName,
@@ -35,21 +44,24 @@ function publishAll() {
   }
 
   for (const out of allOutputs()) {
-    const stateTopic   = `${prefix}/${out.moduleSlug}/output/${out.index}/state`;
-    const cmdTopic     = `${prefix}/${out.moduleSlug}/output/${out.index}/set`;
-    const availTopic   = `${prefix}/${out.moduleSlug}/availability`;
+    const stateTopic = `${prefix}/${out.moduleSlug}/output/${out.index}/state`;
+    const cmdTopic   = `${prefix}/${out.moduleSlug}/output/${out.index}/set`;
+    const availTopic = `${prefix}/${out.moduleSlug}/availability`;
 
     const payload = {
-      name:             out.name,
-      unique_id:        `myprimal_${out.moduleId}_${out.index}`,
-      state_topic:      stateTopic,
-      command_topic:    cmdTopic,
-      payload_on:       JSON.stringify({ action: 'run', duration: 30 }),
-      payload_off:      JSON.stringify({ action: 'stop' }),
-      value_template:   '{{ value_json.value }}',
-      state_on:         '1',
-      state_off:        '0',
-      availability_topic: availTopic,
+      name:                  out.name,
+      unique_id:             `myprimal_${out.moduleId}_${out.index}`,
+      state_topic:           stateTopic,
+      command_topic:         cmdTopic,
+      payload_on:            JSON.stringify({ action: 'run', duration: 30 }),
+      payload_off:           JSON.stringify({ action: 'stop' }),
+      value_template:        '{{ value_json.value }}',
+      state_on:              '1',
+      state_off:             '0',
+      availability_topic:    availTopic,
+      availability_template: AVAIL_TEMPLATE,
+      payload_available:     'online',
+      payload_not_available: 'offline',
       device: {
         identifiers:  [`myprimal_${out.moduleId}`],
         name:         out.moduleName,
@@ -61,16 +73,28 @@ function publishAll() {
     client.publish(configTopic, JSON.stringify(payload), { retain: true });
   }
 
-  // Publish availability online for all modules
+  // Publish availability for all modules (JSON payload)
   const seen = new Set();
   for (const inp of allInputs()) {
     if (!seen.has(inp.moduleSlug)) {
       seen.add(inp.moduleSlug);
-      getClient().publish(`${prefix}/${inp.moduleSlug}/availability`, 'online', { retain: true });
+      client.publish(`${prefix}/${inp.moduleSlug}/availability`, AVAIL_ONLINE, { retain: true });
+    }
+  }
+  for (const out of allOutputs()) {
+    if (!seen.has(out.moduleSlug)) {
+      seen.add(out.moduleSlug);
+      client.publish(`${prefix}/${out.moduleSlug}/availability`, AVAIL_ONLINE, { retain: true });
     }
   }
 
   console.log('[discovery] HA autodiscovery published');
 }
 
-module.exports = { publishAll };
+function publishOffline(moduleSlug) {
+  const client = getClient();
+  if (!client) return;
+  client.publish(`${getPrefix()}/${moduleSlug}/availability`, AVAIL_OFFLINE, { retain: true });
+}
+
+module.exports = { publishAll, publishOffline };