diff --git a/wled00/data/settings_time.htm b/wled00/data/settings_time.htm
index ae29065ead..2fa5c09bb9 100644
--- a/wled00/data/settings_time.htm
+++ b/wled00/data/settings_time.htm
@@ -8,6 +8,8 @@
 	<script>
 	var el=false;
 	var ms=["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"];
+	var maxTimePresets = 16; // Maximum number of time-controlled presets
+	var currentPresetCount = 3; // Current number of presets (sunrise + sunset + 1 permanent time preset)
 	function S() {
 		getLoc();
 		loadJS(getURL('/settings/s.js?p=5'), false, ()=>{BTa();}, ()=>{
@@ -27,60 +29,183 @@
 	function BTa()
 	{
 		var ih="<thead><tr><th>En.</th><th>Hour</th><th>Minute</th><th>Preset</th><th></th></tr></thead>";
-		for (i=0;i<8;i++) {
-			ih+=`<tr><td><input name="W${i}" id="W${i}" type="hidden"><input id="W${i}0" type="checkbox"></td>
-<td><input name="H${i}" class="xs" type="number" min="0" max="24"></td>
-<td><input name="N${i}" class="xs" type="number" min="0" max="59"></td>
+		// Generate sunrise preset (0)
+		ih += generatePresetRow(0, true, "Sunrise");
+		// Generate sunset preset (1)
+		ih += generatePresetRow(1, true, "Sunset");
+		// Generate one permanent time preset (2)
+		ih += generatePresetRow(2, false, null, false);
+		// Generate any additional dynamic presets (starting from 3)
+		for (i=3; i<currentPresetCount; i++) {
+			ih += generatePresetRow(i, false, null, true);
+		}
+		gId("TMT").innerHTML=ih;
+	}
+
+	function generatePresetRow(i, isSunEvent = false, sunType = null, isDynamic = false) {
+		var ih = "";
+		var hourInput = isSunEvent ? 
+			`${sunType}<input name="H${i}" value="255" type="hidden">` : 
+			`<input name="H${i}" class="xs" type="number" min="0" max="24">`;
+		
+		ih += `<tr id="preset-row-${i}"><td><input name="W${i}" id="W${i}" type="hidden"><input id="W${i}0" type="checkbox"></td>
+<td>${hourInput}</td>
+<td><input name="N${i}" class="xs" type="number" min="${isSunEvent ? '-59' : '0'}" max="59"></td>
 <td><input name="T${i}" class="s" type="number" min="0" max="250"></td>
 <td><div id="CB${i}" onclick="expand(this,${i})" class="cal">&#128197;</div></td></tr>`;
-			ih+=`<tr><td colspan=5><div id="WD${i}" style="display:none;background-color:#444;"><hr>Run on weekdays`;
-			ih+=`<table><tr><th>M</th><th>T</th><th>W</th><th>T</th><th>F</th><th>S</th><th>S</th></tr><tr>`
-			for (j=1;j<8;j++) ih+=`<td><input id="W${i}${j}" type="checkbox"></td>`;
-			ih+=`</tr></table>from <select name="M${i}">`;
-			for (j=0;j<12;j++) ih+=`<option value="${j+1}">${ms[j]}</option>`;
-			ih+=`</select><input name="D${i}" class="xs" type="number" min="1" max="31"></input> to <select name="P${i}">`;
-			for (j=0;j<12;j++) ih+=`<option value="${j+1}">${ms[j]}</option>`;
-			ih+=`</select><input name="E${i}" class="xs" type="number" min="1" max="31"></input>
-		<hr></div></td></tr>`;
+		
+		ih += `<tr id="preset-detail-${i}"><td colspan=5><div id="WD${i}" style="display:none;background-color:#444;"><hr>`;
+		
+		if (!isSunEvent) {
+			ih += "Run on weekdays";
+		}
+		
+		ih += `<table><tr><th>M</th><th>T</th><th>W</th><th>T</th><th>F</th><th>S</th><th>S</th></tr><tr>`;
+		for (j=1;j<8;j++) ih += `<td><input id="W${i}${j}" type="checkbox"></td>`;
+		ih += "</tr></table>";
+		
+		if (!isSunEvent) {
+			ih += `from <select name="M${i}">`;
+			for (j=0;j<12;j++) ih += `<option value="${j+1}">${ms[j]}</option>`;
+			ih += `</select><input name="D${i}" class="xs" type="number" min="1" max="31"></input> to <select name="P${i}">`;
+			for (j=0;j<12;j++) ih += `<option value="${j+1}">${ms[j]}</option>`;
+			ih += `</select><input name="E${i}" class="xs" type="number" min="1" max="31"></input>`;
+		}
+		
+		ih += "<hr></div></td></tr>";
+		return ih;
+	}
+
+	function addTimePreset() {
+		if (currentPresetCount >= maxTimePresets) {
+			alert(`Maximum of ${maxTimePresets} time presets allowed.`);
+			return;
+		}
+		
+		var table = gId("TMT");
+		var newRowHTML = generatePresetRow(currentPresetCount, false, null, true);
+		table.insertAdjacentHTML("beforeend", newRowHTML);
+		
+		currentPresetCount++;
+		updateButtonStates();
+	}
+
+	function removePreset(index) {
+		if (index < 3) {
+			alert("Cannot remove built-in presets (Sunrise, Sunset, and first time preset).");
+			return;
+		}
+		
+		// Remove the preset rows
+		var presetRow = gId(`preset-row-${index}`);
+		var detailRow = gId(`preset-detail-${index}`);
+		
+		if (presetRow) presetRow.remove();
+		if (detailRow) detailRow.remove();
+		
+		// Reindex remaining presets
+		reindexPresets();
+		currentPresetCount--;
+		updateButtonStates();
+	}
+
+	function removeLastPreset() {
+		if (currentPresetCount <= 3) {
+			alert("Cannot remove built-in presets. Only dynamic presets (3+) can be removed.");
+			return;
+		}
+		
+		// Find the highest index dynamic preset and remove it
+		var lastIndex = currentPresetCount - 1;
+		removePreset(lastIndex);
+	}
+
+	function reindexPresets() {
+		var table = gId("TMT");
+		var rows = table.querySelectorAll("tr[id^='preset-row-']");
+		var newIndex = 3;
+		
+		rows.forEach((row) => {
+			var oldIndex = row.id.split('-')[2];
+			if (parseInt(oldIndex) >= 3) {
+				updatePresetRowIndex(row, oldIndex, newIndex);
+				var detailRow = gId(`preset-detail-${oldIndex}`);
+				if (detailRow) {
+					updatePresetDetailRowIndex(detailRow, oldIndex, newIndex);
+				}
+				newIndex++;
+			}
+		});
+	}
+
+	function updatePresetRowIndex(row, oldIndex, newIndex) {
+		row.id = `preset-row-${newIndex}`;
+		row.innerHTML = row.innerHTML
+			.replace(new RegExp(`name="W${oldIndex}"`, 'g'), `name="W${newIndex}"`)
+			.replace(new RegExp(`id="W${oldIndex}`, 'g'), `id="W${newIndex}`)
+			.replace(new RegExp(`name="H${oldIndex}"`, 'g'), `name="H${newIndex}"`)
+			.replace(new RegExp(`name="N${oldIndex}"`, 'g'), `name="N${newIndex}"`)
+			.replace(new RegExp(`name="T${oldIndex}"`, 'g'), `name="T${newIndex}"`)
+			.replace(new RegExp(`id="CB${oldIndex}"`, 'g'), `id="CB${newIndex}"`)
+			.replace(new RegExp(`expand\(this,${oldIndex}\)`, 'g'), `expand(this,${newIndex})`)
+			.replace(new RegExp(`removePreset\(${oldIndex}\)`, 'g'), `removePreset(${newIndex})`);
+	}
+
+	function updatePresetDetailRowIndex(row, oldIndex, newIndex) {
+		row.id = `preset-detail-${newIndex}`;
+		row.innerHTML = row.innerHTML
+			.replace(new RegExp(`id="WD${oldIndex}"`, 'g'), `id="WD${newIndex}"`)
+			.replace(new RegExp(`id="W${oldIndex}`, 'g'), `id="W${newIndex}`)
+			.replace(new RegExp(`name="M${oldIndex}"`, 'g'), `name="M${newIndex}"`)
+			.replace(new RegExp(`name="D${oldIndex}"`, 'g'), `name="D${newIndex}"`)
+			.replace(new RegExp(`name="P${oldIndex}"`, 'g'), `name="P${newIndex}"`)
+			.replace(new RegExp(`name="E${oldIndex}"`, 'g'), `name="E${newIndex}"`);
+	}
+
+	function updateButtonStates() {
+		var addBtn = gId("addPresetBtn");
+		var removeBtn = gId("removePresetBtn");
+		
+		if (addBtn) {
+			addBtn.disabled = currentPresetCount >= maxTimePresets;
+		}
+		
+		if (removeBtn) {
+			removeBtn.disabled = currentPresetCount <= 3;
 		}
-		ih+=`<tr><td><input name="W8" id="W8" type="hidden"><input id="W80" type="checkbox"></td>
-<td>Sunrise<input name="H8" value="255" type="hidden"></td>
-<td><input name="N8" class="xs" type="number" min="-59" max="59"></td>
-<td><input name="T8" class="s" type="number" min="0" max="250"></td>
-<td><div id="CB8" onclick="expand(this,8)" class="cal">&#128197;</div></td></tr><tr><td colspan=5>`;
-		ih+=`<div id="WD8" style="display:none;background-color:#444;"><hr><table><tr><th>M</th><th>T</th><th>W</th><th>T</th><th>F</th><th>S</th><th>S</th></tr><tr>`;
-		for (j=1;j<8;j++) ih+=`<td><input id="W8${j}" type="checkbox"></td>`;
-		ih+="</tr></table><hr></div></td></tr>";
-		ih+=`<tr><td><input name="W9" id="W9" type="hidden"><input id="W90" type="checkbox"></td>
-<td>Sunset<input name="H9" value="255" type="hidden"></td>
-<td><input name="N9" class="xs" type="number" min="-59" max="59"></td>
-<td><input name="T9" class="s" type="number" min="0" max="250"></td>
-<td><div id="CB9" onclick="expand(this,9)" class="cal">&#128197;</div></td></tr><tr><td colspan=5>`;
-		ih+=`<div id="WD9" style="display:none;background-color:#444;"><hr><table><tr><th>M</th><th>T</th><th>W</th><th>T</th><th>F</th><th>S</th><th>S</th></tr><tr>`;
-		for (j=1;j<8;j++) ih+=`<td><input id="W9${j}" type="checkbox"></td>`;
-		ih+="</tr></table><hr></div></td></tr>";
-		gId("TMT").innerHTML=ih;
 	}
 	function FC()
 	{
-		for(i=0;i<10;i++)
+		for(i=0;i<currentPresetCount;i++)
 		{
-			let wd = gId("W"+i).value;
+			let wd = gId("W"+i);
+			if (!wd) continue; // Skip if preset doesn't exist
+			wd = wd.value;
 			for(j=0;j<8;j++) {
-				gId("W"+i+j).checked=wd>>j&1;
+				let checkbox = gId("W"+i+j);
+				if (checkbox) checkbox.checked=wd>>j&1;
 			}
-			if ((wd&254) != 254 || (i<8 && (gN("M"+i).value != 1 || gN("D"+i).value != 1 || gN("P"+i).value != 12 || gN("E"+i).value != 31))) {
-				expand(gId("CB"+i),i); //expand macros with custom DOW or date range set
+			if ((wd&254) != 254 || (i<8 && (gN("M"+i) && gN("D"+i) && gN("P"+i) && gN("E"+i) && 
+				(gN("M"+i).value != 1 || gN("D"+i).value != 1 || gN("P"+i).value != 12 || gN("E"+i).value != 31)))) {
+				let cbElement = gId("CB"+i);
+				if (cbElement) expand(cbElement,i); //expand macros with custom DOW or date range set
 			}
 		}
+		updateAddButtonState();
 	}
 	function Wd()
 	{
-		a = [0,0,0,0,0,0,0,0,0,0];
-		for (i=0; i<10; i++) {
+		a = [];
+		for (i=0; i<currentPresetCount; i++) {
+			a[i] = 0;
 			m=1;
-			for(j=0;j<8;j++) { a[i]+=gId(("W"+i)+j).checked*m; m*=2;}
-			gId("W"+i).value=a[i];
+			for (j=0; j<8; j++) {
+				let checkbox = gId("W"+i+j);
+				if (checkbox && checkbox.checked) a[i]+=m;
+				m*=2;
+			}
+			let hiddenInput = gId("W"+i);
+			if (hiddenInput) hiddenInput.value = a[i];
 		}
 		if (d.Sf.LTR.value==="S") { d.Sf.LT.value = -1*parseFloat(d.Sf.LT.value); }
 		if (d.Sf.LNR.value==="W") { d.Sf.LN.value = -1*parseFloat(d.Sf.LN.value); }
@@ -178,6 +303,11 @@ <h3>Clock</h3>
 		Countdown Goal:<br>
 		Date:&nbsp;<nowrap>20<input name="CY" class="xs" type="number" min="0" max="99" required>-<input name="CI" class="xs" type="number" min="1" max="12" required>-<input name="CD" class="xs" type="number" min="1" max="31" required></nowrap><br>
 		Time:&nbsp;<nowrap><input name="CH" class="xs" type="number" min="0" max="23" required>:<input name="CM" class="xs" type="number" min="0" max="59" required>:<input name="CS" class="xs" type="number" min="0" max="59" required></nowrap><br>
+		<h3>Upload Schedule JSON</h3>
+		<input type="file" name="scheduleFile" id="scheduleFile" accept=".json">
+		<input type="button" value="Upload" onclick="uploadFile(d.Sf.scheduleFile, '/schedule.json');">
+		<br>
+		<a class="btn lnk" id="bckschedule" href="/schedule.json" download="schedule">Backup schedule</a><br>
 		<h3>Macro presets</h3>
 		<b>Macros have moved!</b><br>
 		<i>Presets now also can be used as macros to save both JSON and HTTP API commands.<br>
@@ -202,7 +332,10 @@ <h3>Button actions</h3>
 		<a href="https://kno.wled.ge/features/macros/#analog-button" target="_blank">Analog Button setup</a>
 		<h3>Time-controlled presets</h3>
 		<div style="display: inline-block">
-		<table id="TMT" style="min-width:330px;"></table>
+		<table id="TMT" style="min-width:380px; margin: 0 auto;"></table>
+		<br>
+		<button type="button" id="addPresetBtn" onclick="addTimePreset()">+</button>
+		<button type="button" id="removePresetBtn" onclick="removeLastPreset()" style="margin-left: 5px;">-</button>
 		</div>
 		<hr>
 		<button type="button" onclick="B()">Back</button><button type="submit">Save</button>
diff --git a/wled00/schedule.cpp b/wled00/schedule.cpp
new file mode 100644
index 0000000000..e805547d4e
--- /dev/null
+++ b/wled00/schedule.cpp
@@ -0,0 +1,141 @@
+// schedule.cpp
+// Handles reading, parsing, and checking the preset schedule from schedule.json
+
+#include "schedule.h"
+#include "wled.h"
+#include <time.h>
+#include <vector>
+
+#define SCHEDULE_FILE "/schedule.json"
+#define SCHEDULE_JSON_BUFFER_SIZE 4096
+
+// Array to hold scheduled events, max size defined in schedule.h
+std::vector<ScheduleEvent> scheduleEvents;
+
+// Helper function to check if current date (cm, cd) is within the event's start and end date range
+bool isTodayInRange(uint8_t sm, uint8_t sd, uint8_t em, uint8_t ed, uint8_t cm, uint8_t cd)
+{
+    // Handles ranges that wrap over the year end, e.g., Dec to Jan
+    if (sm < em || (sm == em && sd <= ed)) {
+        // Normal range within a year
+        return (cm > sm || (cm == sm && cd >= sd)) &&
+               (cm < em || (cm == em && cd <= ed));
+    }
+    else {
+        // Range wraps year-end (e.g., Nov 20 to Feb 10)
+        return (cm > sm || (cm == sm && cd >= sd)) ||
+               (cm < em || (cm == em && cd <= ed));
+    }
+}
+
+// Checks current time against schedule entries and applies matching presets
+void checkSchedule() {
+    static int lastMinute = -1; // To avoid multiple triggers within the same minute
+
+    time_t now = localTime;
+    if (now < 100000) return; // Invalid or uninitialized time guard
+
+    struct tm* timeinfo = localtime(&now);
+
+    int thisMinute = timeinfo->tm_min + timeinfo->tm_hour * 60;
+    if (thisMinute == lastMinute) return; // Already checked this minute
+    lastMinute = thisMinute;
+
+    // Extract date/time components for easier use
+    uint8_t cm = timeinfo->tm_mon + 1; // Month [1-12]
+    uint8_t cd = timeinfo->tm_mday;    // Day of month [1-31]
+    uint8_t wday = timeinfo->tm_wday;  // Weekday [0-6], Sunday=0
+    uint8_t hr = timeinfo->tm_hour;    // Hour [0-23]
+    uint8_t min = timeinfo->tm_min;    // Minute [0-59]
+
+    DEBUG_PRINTF_P(PSTR("[Schedule] Checking schedule at %02u:%02u\n"), hr, min);
+
+    // Iterate through all scheduled events
+    for (size_t i = 0; i < scheduleEvents.size(); i++) {
+        const ScheduleEvent &e = scheduleEvents[i];
+
+        // Skip if hour or minute doesn't match current time
+        if (e.hour != hr || e.minute != min)
+            continue;
+
+        bool match = false;
+
+        // Check if repeat mask matches current weekday (bitmask with Sunday=LSB)
+        if (e.repeatMask && ((e.repeatMask >> wday) & 0x01))
+            match = true;
+
+        // Otherwise check if current date is within start and end date range
+        if (e.startMonth) {
+            if (isTodayInRange(e.startMonth, e.startDay, e.endMonth, e.endDay, cm, cd))
+                match = true;
+        }
+
+        // If match, apply preset and print debug
+        if (match) {
+            applyPreset(e.presetId);
+            DEBUG_PRINTF_P(PSTR("[Schedule] Applying preset %u at %02u:%02u\n"), e.presetId, hr, min);
+        }
+    }
+}
+
+// Loads schedule events from the schedule JSON file
+// Returns true if successful, false on error or missing file
+bool loadSchedule() {
+    if (!WLED_FS.exists(SCHEDULE_FILE)) return false;
+
+    // Acquire JSON buffer lock to prevent concurrent access
+    if (!requestJSONBufferLock(7)) return false;
+
+    File file = WLED_FS.open(SCHEDULE_FILE, "r");
+    if (!file) {
+        releaseJSONBufferLock();
+        return false;
+    }
+
+    DynamicJsonDocument doc(SCHEDULE_JSON_BUFFER_SIZE);
+    DeserializationError error = deserializeJson(doc, file);
+    file.close();  // Always close file before releasing lock
+
+    if (error) {
+        DEBUG_PRINTF_P(PSTR("[Schedule] JSON parse failed: %s\n"), error.c_str());
+        releaseJSONBufferLock();
+        return false;
+    }
+
+    scheduleEvents.clear();
+    for (JsonObject e : doc.as<JsonArray>()) {
+
+        // Read and validate fields with type safety
+        int sm = e["sm"].as<int>();
+        int sd = e["sd"].as<int>();
+        int em = e["em"].as<int>();
+        int ed = e["ed"].as<int>();
+        int r  = e["r"].as<int>();
+        int h  = e["h"].as<int>();
+        int m  = e["m"].as<int>();
+        int p  = e["p"].as<int>();
+
+        // Validate ranges to prevent bad data
+        if (sm < 1 || sm > 12 || em < 1 || em > 12 ||
+            sd < 1 || sd > 31 || ed < 1 || ed > 31 ||
+            h  < 0 || h  > 23 || m  < 0 || m  > 59 ||
+            r  < 0 || r  > 127|| p  < 1 || p  > 250) {
+            DEBUG_PRINTF_P(PSTR("[Schedule] Invalid values in event %u, skipping\n"), (uint16_t)scheduleEvents.size());
+            continue;
+        }
+
+        scheduleEvents.push_back({
+            (uint8_t)sm, (uint8_t)sd,
+            (uint8_t)em, (uint8_t)ed,
+            (uint8_t)r,  (uint8_t)h,
+            (uint8_t)m,  (uint8_t)p
+        });
+    }
+
+    DEBUG_PRINTF_P(PSTR("[Schedule] Loaded %u schedule entries from schedule.json\n"), (uint16_t)scheduleEvents.size());
+
+    // Release JSON buffer lock after finishing
+    releaseJSONBufferLock();
+
+    return true;
+}
diff --git a/wled00/schedule.h b/wled00/schedule.h
new file mode 100644
index 0000000000..c94764f96f
--- /dev/null
+++ b/wled00/schedule.h
@@ -0,0 +1,33 @@
+// schedule.h
+// Defines the schedule event data structure and declares schedule-related functions
+
+#pragma once
+
+#include <stdint.h>
+
+// Maximum number of schedule events supported
+#define MAX_SCHEDULE_EVENTS 32
+
+struct ScheduleEvent {
+  uint8_t startMonth : 4;  // 0–12 (0 means no date range)
+  uint8_t startDay   : 5;  // 0–31
+
+  uint8_t endMonth   : 4;  // 0–12
+  uint8_t endDay     : 5;  // 0–31
+
+  uint8_t repeatMask : 7;  // bitmask for days of week (Sun=bit0 .. Sat=bit6)
+
+  uint8_t hour       : 5;  // 0–23
+  uint8_t minute     : 6;  // 0–59
+
+  uint8_t presetId;        // 1–250
+};
+
+// Loads the schedule from the JSON file; returns true if successful
+bool loadSchedule();
+
+// Checks current time against schedule and applies any matching preset
+void checkSchedule();
+
+// Checks if the current date is within the specified range
+bool isTodayInRange(uint8_t sm, uint8_t sd, uint8_t em, uint8_t ed, uint8_t cm, uint8_t cd);
\ No newline at end of file
diff --git a/wled00/wled.cpp b/wled00/wled.cpp
index c372d22abd..a6067a552f 100644
--- a/wled00/wled.cpp
+++ b/wled00/wled.cpp
@@ -2,6 +2,7 @@
 #include "wled.h"
 #include "wled_ethernet.h"
 #include <Arduino.h>
+#include "schedule.h"
 
 #if defined(ARDUINO_ARCH_ESP32) && defined(WLED_DISABLE_BROWNOUT_DET)
 #include "soc/soc.h"
@@ -54,6 +55,7 @@ void WLED::loop()
 #endif
 
   handleTime();
+  checkSchedule();
   #ifndef WLED_DISABLE_INFRARED
   handleIR();        // 2nd call to function needed for ESP32 to return valid results -- should be good for ESP8266, too
   #endif
@@ -414,6 +416,8 @@ void WLED::setup()
 #endif
   updateFSInfo();
 
+  loadSchedule();   // Load schedule from file on startup
+
   // generate module IDs must be done before AP setup
   escapedMac = WiFi.macAddress();
   escapedMac.replace(":", "");
diff --git a/wled00/wled_server.cpp b/wled00/wled_server.cpp
index 4434a2f3e5..aa0e2205ed 100644
--- a/wled00/wled_server.cpp
+++ b/wled00/wled_server.cpp
@@ -15,6 +15,7 @@
   #include "html_pxmagic.h"
 #endif
 #include "html_cpal.h"
+#include "schedule.h"
 
 // define flash strings once (saves flash memory)
 static const char s_redirecting[] PROGMEM = "Redirecting...";
@@ -25,6 +26,8 @@ static const char s_rebooting  [] PROGMEM = "Rebooting now...";
 static const char s_notimplemented[] PROGMEM = "Not implemented";
 static const char s_accessdenied[]   PROGMEM = "Access Denied";
 static const char _common_js[]       PROGMEM = "/common.js";
+static const char SCHEDULE_JSON_PATH[] PROGMEM = "/schedule.json";
+static const char SCHEDULE_JSON_TMP_PATH[] PROGMEM = "/schedule.json.tmp";
 
 //Is this an IP?
 static bool isIp(const String &str) {
@@ -174,33 +177,86 @@ static String msgProcessor(const String& var)
   return String();
 }
 
-static void handleUpload(AsyncWebServerRequest *request, const String& filename, size_t index, uint8_t *data, size_t len, bool isFinal) {
+static void handleUpload(AsyncWebServerRequest *request, const String &filename, size_t index, uint8_t *data, size_t len, bool isFinal){
   if (!correctPIN) {
-    if (isFinal) request->send(401, FPSTR(CONTENT_TYPE_PLAIN), FPSTR(s_unlock_cfg));
+    if (isFinal)
+      request->send(401, FPSTR(CONTENT_TYPE_PLAIN), FPSTR(s_unlock_cfg));
     return;
   }
+
+  String finalname = filename;
   if (!index) {
-    String finalname = filename;
     if (finalname.charAt(0) != '/') {
       finalname = '/' + finalname; // prepend slash if missing
     }
 
-    request->_tempFile = WLED_FS.open(finalname, "w");
-    DEBUG_PRINTF_P(PSTR("Uploading %s\n"), finalname.c_str());
-    if (finalname.equals(FPSTR(getPresetsFileName()))) presetsModifiedTime = toki.second();
+    // Special case: schedule.json upload uses temp file
+    if (finalname.equals(FPSTR(SCHEDULE_JSON_PATH))) {
+      request->_tempFile = WLED_FS.open(FPSTR(SCHEDULE_JSON_TMP_PATH), "w");
+      DEBUG_PRINTLN(F("Uploading to /schedule.json.tmp"));
+    }
+    else {
+      request->_tempFile = WLED_FS.open(finalname, "w");
+      DEBUG_PRINTF_P(PSTR("Uploading %s\n"), finalname.c_str());
+
+      if (finalname.equals(FPSTR(getPresetsFileName()))) {
+        presetsModifiedTime = toki.second();
+      }
+    }
   }
-  if (len) {
-    request->_tempFile.write(data,len);
+
+  // Write chunk
+  if (len && request->_tempFile) {
+    size_t written = request->_tempFile.write(data, len);
+    if (written != len) {
+      DEBUG_PRINTLN(F("File write error during upload"));
+      request->_tempFile.close();
+      request->_tempFile = File(); // invalidate file handle
+      // Consider sending error response early
+    }
   }
+
+  // Finalize upload
   if (isFinal) {
-    request->_tempFile.close();
-    if (filename.indexOf(F("cfg.json")) >= 0) { // check for filename with or without slash
-      doReboot = true;
-      request->send(200, FPSTR(CONTENT_TYPE_PLAIN), F("Configuration restore successful.\nRebooting..."));
-    } else {
-      if (filename.indexOf(F("palette")) >= 0 && filename.indexOf(F(".json")) >= 0) loadCustomPalettes();
-      request->send(200, FPSTR(CONTENT_TYPE_PLAIN), F("File Uploaded!"));
+    if (request->_tempFile)
+      request->_tempFile.close();
+
+    if (finalname.equals(FPSTR(SCHEDULE_JSON_PATH))) {
+      // Atomically replace old file
+      // First try rename (which overwrites on most filesystems)
+      if (!WLED_FS.rename(FPSTR(SCHEDULE_JSON_TMP_PATH), FPSTR(SCHEDULE_JSON_PATH))) {
+        // If rename failed, try remove then rename
+        WLED_FS.remove(FPSTR(SCHEDULE_JSON_PATH));
+        if (!WLED_FS.rename(FPSTR(SCHEDULE_JSON_TMP_PATH), FPSTR(SCHEDULE_JSON_PATH))) {
+          DEBUG_PRINTLN(F("[Schedule] Failed to replace schedule file"));
+          request->send(500, FPSTR(CONTENT_TYPE_PLAIN), F("Failed to save schedule file."));
+          return;
+        }
+      }
+      request->send(200, FPSTR(CONTENT_TYPE_PLAIN), F("Schedule uploaded and applied."));
+      DEBUG_PRINTLN(F("[Schedule] Upload complete and applied."));
+
+      // Apply new schedule immediately
+      if (!loadSchedule()) {
+        DEBUG_PRINTLN(F("[Schedule] Failed to load new schedule"));
+        request->send(500, FPSTR(CONTENT_TYPE_PLAIN), F("Schedule uploaded but failed to load."));
+        return;
+      }
+    }
+    else
+    {
+      if (filename.indexOf(F("cfg.json")) >= 0) {
+        doReboot = true;
+        request->send(200, FPSTR(CONTENT_TYPE_PLAIN), F("Configuration restore successful.\nRebooting..."));
+      }
+      else {
+        if (filename.indexOf(F("palette")) >= 0 && filename.indexOf(F(".json")) >= 0) {
+          loadCustomPalettes();
+        }
+        request->send(200, FPSTR(CONTENT_TYPE_PLAIN), F("File Uploaded!"));
+      }
     }
+
     cacheInvalidate++;
   }
 }