diff --git a/src/main/java/com/flippingutilities/model/OfferEvent.java b/src/main/java/com/flippingutilities/model/OfferEvent.java
index 2afe02e..b44361e 100644
--- a/src/main/java/com/flippingutilities/model/OfferEvent.java
+++ b/src/main/java/com/flippingutilities/model/OfferEvent.java
@@ -93,8 +93,10 @@ public class OfferEvent
 
 	//Used in theGeHistoryTabOfferPanel and RecipeFlipPanel
 	private transient String itemName;
-	//used in the live slot view to show what price something was listed at
-	private transient int listedPrice;
+	//used in the live slot view to show what price something was listed at.
+	//persisted so external tools can see the offer price for unfilled slots.
+	@SerializedName("lp")
+	private int listedPrice;
 	private transient int spent;
 
 	/**
diff --git a/src/test/java/com/flippingutilities/OfferEventSerializationTest.java b/src/test/java/com/flippingutilities/OfferEventSerializationTest.java
new file mode 100644
index 0000000..fe7287d
--- /dev/null
+++ b/src/test/java/com/flippingutilities/OfferEventSerializationTest.java
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2020, Belieal <https://github.com/Belieal>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package com.flippingutilities;
+
+import com.flippingutilities.model.OfferEvent;
+import com.google.gson.Gson;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+import net.runelite.api.GrandExchangeOfferState;
+import net.runelite.http.api.RuneLiteAPI;
+import org.junit.Test;
+
+import java.time.Instant;
+import java.util.UUID;
+
+import static org.junit.Assert.*;
+
+public class OfferEventSerializationTest
+{
+	private final Gson gson = RuneLiteAPI.GSON;
+
+	@Test
+	public void listedPriceSurvivesRoundTrip()
+	{
+		OfferEvent offer = new OfferEvent(
+			UUID.randomUUID().toString(),
+			false,       // selling
+			2283,        // item id
+			0,           // currentQuantityInTrade (nothing filled)
+			0,           // price (no fills yet)
+			Instant.parse("2024-01-01T00:00:00Z"),
+			1,           // slot
+			GrandExchangeOfferState.SELLING,
+			0,           // tickArrivedAt
+			0,           // ticksSinceFirstOffer
+			1560,        // totalQuantityInTrade
+			null,        // tradeStartedAt
+			false,       // beforeLogin
+			null,        // madeBy (transient)
+			null,        // itemName (transient)
+			136,         // listedPrice — the offer price we want persisted
+			0);          // spent (transient)
+
+		String json = gson.toJson(offer);
+
+		// Verify "lp" key is present in output
+		JsonObject obj = new JsonParser().parse(json).getAsJsonObject();
+		assertTrue("JSON should contain 'lp' key", obj.has("lp"));
+		assertEquals(136, obj.get("lp").getAsInt());
+
+		// Round-trip: deserialize and verify listedPrice survived
+		OfferEvent restored = gson.fromJson(json, OfferEvent.class);
+		assertEquals(136, restored.getListedPrice());
+		assertEquals(2283, restored.getItemId());
+		assertEquals(0, restored.getPreTaxPrice());
+		assertEquals(1560, restored.getTotalQuantityInTrade());
+		assertEquals(GrandExchangeOfferState.SELLING, restored.getState());
+	}
+
+	@Test
+	public void oldJsonWithoutListedPriceDefaultsToZero()
+	{
+		// Simulate JSON from before this change — no "lp" field
+		String oldJson = "{\"uuid\":\"abc\",\"b\":true,\"id\":4151,\"cQIT\":10,\"p\":1500,"
+			+ "\"t\":{\"seconds\":1704067200,\"nanos\":0},"
+			+ "\"s\":3,\"st\":\"BUYING\",\"tAA\":0,\"tSFO\":5,\"tQIT\":100}";
+
+		OfferEvent restored = gson.fromJson(oldJson, OfferEvent.class);
+		assertEquals(0, restored.getListedPrice());
+		assertEquals(4151, restored.getItemId());
+		assertEquals(100, restored.getTotalQuantityInTrade());
+	}
+}
diff --git a/src/test/java/com/flippingutilities/TestRunner.java b/src/test/java/com/flippingutilities/TestRunner.java
index c08bead..6e84160 100644
--- a/src/test/java/com/flippingutilities/TestRunner.java
+++ b/src/test/java/com/flippingutilities/TestRunner.java
@@ -36,7 +36,8 @@
 @RunWith(Suite.class)
 @Suite.SuiteClasses({
 	HistoryManagerTest.class,
-	FlippingPluginTest.class
+	FlippingPluginTest.class,
+	OfferEventSerializationTest.class
 })
 public class TestRunner {