diff --git a/web/src/components/CaseBuilder/BusesTable.tsx b/web/src/components/CaseBuilder/BusesTable.tsx
index 25cdc0e..f14f081 100644
--- a/web/src/components/CaseBuilder/BusesTable.tsx
+++ b/web/src/components/CaseBuilder/BusesTable.tsx
@@ -6,7 +6,7 @@
 
 import Papa from "papaparse";
 import { Buses, UnitCommitmentScenario } from "../../core/fixtures";
-import { useEffect, useRef } from "react";
+import { useEffect, useRef, useState } from "react";
 import {
   CellComponent,
   ColumnDefinition,
@@ -154,21 +154,21 @@ interface BusesTableProps {
 
 function computeBusesTableHeight(scenario: UnitCommitmentScenario): string {
   const numBuses = Object.keys(scenario.Buses).length;
-  const height = 65 + Math.min(numBuses, 15) * 28;
+  const height = 70 + Math.min(numBuses, 15) * 28;
   return `${height}px`;
 }
 
 function BusesTable(props: BusesTableProps) {
   const tableContainerRef = useRef<HTMLDivElement | null>(null);
+  const tableRef = useRef<Tabulator | null>(null);
+  const [isTableBuilt, setTableBuilt] = useState<Boolean>(false);
 
   useEffect(() => {
-    const scenario = props.scenario;
     const onCellEdited = (cell: CellComponent) => {
       let newValue = cell.getValue();
       let oldValue = cell.getOldValue();
       // eslint-disable-next-line eqeqeq
       if (newValue == oldValue) return;
-
       if (cell.getField() === "Name") {
         if (newValue === "") {
           props.onBusDeleted(oldValue);
@@ -188,18 +188,54 @@ function BusesTable(props: BusesTableProps) {
         }
       }
     };
-
     if (tableContainerRef.current === null) return;
-    const table = new Tabulator(tableContainerRef.current, {
-      layout: "fitColumns",
-      data: generateBusesTableData(scenario),
-      columns: generateBusesTableColumns(scenario),
-      height: computeBusesTableHeight(scenario),
-    });
-    table.on("cellEdited", (cell) => {
-      onCellEdited(cell);
-    });
-  }, [props]);
+    if (tableRef.current === null) {
+      tableRef.current = new Tabulator(tableContainerRef.current, {
+        layout: "fitColumns",
+        data: generateBusesTableData(props.scenario),
+        columns: generateBusesTableColumns(props.scenario),
+        height: computeBusesTableHeight(props.scenario),
+      });
+      tableRef.current.on("tableBuilt", () => {
+        setTableBuilt(true);
+      });
+    }
+    if (isTableBuilt) {
+      const newHeight = computeBusesTableHeight(props.scenario);
+      const newColumns = generateBusesTableColumns(props.scenario);
+      const newData = generateBusesTableData(props.scenario);
+      const oldRows = tableRef.current.getRows();
+
+      // Update data
+      tableRef.current.replaceData(newData).then(() => {});
+
+      // Update columns
+      if (newColumns.length !== tableRef.current.getColumns().length) {
+        tableRef.current.setColumns(newColumns);
+      }
+
+      // Update height
+      if (tableRef.current.options.height !== newHeight) {
+        tableRef.current.setHeight(newHeight);
+      }
+
+      // Scroll to bottom
+      if (tableRef.current.getRows().length === oldRows.length + 1) {
+        setTimeout(() => {
+          const rows = tableRef.current!.getRows()!;
+          const lastRow = rows[rows.length - 1]!;
+          lastRow.scrollTo().then((r) => {});
+          lastRow.getCell("Name").edit();
+        }, 10);
+      }
+
+      // Update callbacks
+      tableRef.current.off("cellEdited");
+      tableRef.current.on("cellEdited", (cell) => {
+        onCellEdited(cell);
+      });
+    }
+  }, [props, isTableBuilt]);
 
   return <div className="tableContainer" ref={tableContainerRef} />;
 }
diff --git a/web/src/components/CaseBuilder/CaseBuilder.tsx b/web/src/components/CaseBuilder/CaseBuilder.tsx
index dfdaa05..9539355 100644
--- a/web/src/components/CaseBuilder/CaseBuilder.tsx
+++ b/web/src/components/CaseBuilder/CaseBuilder.tsx
@@ -26,16 +26,27 @@ import {
   renameBus,
 } from "../../core/Operations/busOperations";
 import {
+  changeParameter,
   changeTimeHorizon,
   changeTimeStep,
 } from "../../core/Operations/parameterOperations";
 import { preprocess } from "../../core/Operations/preprocessing";
+import Toast from "../Common/Forms/Toast";
 
 const CaseBuilder = () => {
-  const [scenario, setScenario] = useState(TEST_SCENARIO);
+  const [scenario, setScenario] = useState(() => {
+    const savedScenario = localStorage.getItem("scenario");
+    return savedScenario ? JSON.parse(savedScenario) : TEST_SCENARIO;
+  });
+  const [toastMessage, setToastMessage] = useState<string>("");
+
+  const setAndSaveScenario = (scenario: UnitCommitmentScenario) => {
+    setScenario(scenario);
+    localStorage.setItem("scenario", JSON.stringify(scenario));
+  };
 
   const onClear = () => {
-    setScenario(BLANK_SCENARIO);
+    setAndSaveScenario(BLANK_SCENARIO);
   };
 
   const onSave = () => {
@@ -48,7 +59,7 @@ const CaseBuilder = () => {
 
   const onBusCreated = () => {
     const newScenario = createBus(scenario);
-    setScenario(newScenario);
+    setAndSaveScenario(newScenario);
   };
 
   const onBusDataChanged = (
@@ -58,16 +69,16 @@ const CaseBuilder = () => {
   ): ValidationError | null => {
     const [newScenario, err] = changeBusData(bus, field, newValue, scenario);
     if (err) {
-      console.log(err);
+      setToastMessage(err.message);
       return err;
     }
-    setScenario(newScenario);
+    setAndSaveScenario(newScenario);
     return null;
   };
 
   const onBusDeleted = (bus: string) => {
     const newScenario = deleteBus(bus, scenario);
-    setScenario(newScenario);
+    setAndSaveScenario(newScenario);
   };
 
   const onBusRenamed = (
@@ -76,15 +87,15 @@ const CaseBuilder = () => {
   ): ValidationError | null => {
     const [newScenario, err] = renameBus(oldName, newName, scenario);
     if (err) {
-      console.log(err);
+      setToastMessage(err.message);
       return err;
     }
-    setScenario(newScenario);
+    setAndSaveScenario(newScenario);
     return null;
   };
 
   const onDataChanged = (newScenario: UnitCommitmentScenario) => {
-    setScenario(newScenario);
+    setAndSaveScenario(newScenario);
   };
 
   const onLoad = (scenario: UnitCommitmentScenario) => {
@@ -94,32 +105,29 @@ const CaseBuilder = () => {
 
     // Validate and assign default values
     if (!validate(preprocessed)) {
+      setToastMessage("Error loading JSON file");
       console.error(validate.errors);
       return;
     }
-    setScenario(preprocessed);
+
+    setAndSaveScenario(preprocessed);
+    setToastMessage("Data loaded successfully");
   };
 
   const onParameterChanged = (key: string, value: string) => {
+    let newScenario, err;
     if (key === "Time horizon (h)") {
-      const [newScenario, err] = changeTimeHorizon(scenario, value);
-      if (err) {
-        return err;
-      }
-      setScenario(newScenario);
-      return null;
+      [newScenario, err] = changeTimeHorizon(scenario, value);
+    } else if (key === "Time step (min)") {
+      [newScenario, err] = changeTimeStep(scenario, value);
+    } else {
+      [newScenario, err] = changeParameter(scenario, key, value);
     }
-
-    if (key === "Time step (min)") {
-      const [newScenario, err] = changeTimeStep(scenario, value);
-      if (err) {
-        return err;
-      }
-      setScenario(newScenario);
-      return null;
+    if (err) {
+      setToastMessage(err.message);
+      return err;
     }
-
-    console.log("onParameterChanged", key, value);
+    setAndSaveScenario(newScenario);
     return null;
   };
 
@@ -139,6 +147,7 @@ const CaseBuilder = () => {
           onBusDeleted={onBusDeleted}
           onDataChanged={onDataChanged}
         />
+        <Toast message={toastMessage} />
       </div>
       <Footer />
     </div>
diff --git a/web/src/components/Common/Forms/Toast.module.css b/web/src/components/Common/Forms/Toast.module.css
new file mode 100644
index 0000000..1d215ca
--- /dev/null
+++ b/web/src/components/Common/Forms/Toast.module.css
@@ -0,0 +1,23 @@
+/*
+ * UnitCommitment.jl: Optimization Package for Security-Constrained Unit Commitment
+ * Copyright (C) 2020-2025, UChicago Argonne, LLC. All rights reserved.
+ * Released under the modified BSD license. See COPYING.md for more details.
+ */
+
+.Toast {
+    width: 600px;
+    border-radius: var(--border-radius);
+    box-shadow: 4px 4px 16px -2px rgba(0, 0, 0, 0.5);
+    margin: 0 auto;
+    background-color: #424242;
+    color: white;
+    padding: 0 16px;
+    position: fixed;
+    top: 48px;
+    left: 50%;
+    transform: translate(-50%, 0);
+    transition: opacity 0.5s ease;
+    cursor: default;
+    font-size: 15px;
+    line-height: 48px;
+}
\ No newline at end of file
diff --git a/web/src/components/Common/Forms/Toast.tsx b/web/src/components/Common/Forms/Toast.tsx
new file mode 100644
index 0000000..5178276
--- /dev/null
+++ b/web/src/components/Common/Forms/Toast.tsx
@@ -0,0 +1,35 @@
+/*
+ * UnitCommitment.jl: Optimization Package for Security-Constrained Unit Commitment
+ * Copyright (C) 2020-2025, UChicago Argonne, LLC. All rights reserved.
+ * Released under the modified BSD license. See COPYING.md for more details.
+ */
+
+import styles from "./Toast.module.css";
+import { useEffect, useState } from "react";
+
+interface ToastProps {
+  message: string;
+}
+
+const Toast = (props: ToastProps) => {
+  const [isVisible, setVisible] = useState(true);
+
+  useEffect(() => {
+    if (props.message.length === 0) return;
+    setVisible(true);
+    const timer = setTimeout(() => {
+      setVisible(false);
+    }, 5000);
+    return () => clearTimeout(timer);
+  }, [props.message]);
+
+  return (
+    <div>
+      <div className={styles.Toast} style={{ opacity: isVisible ? 1 : 0 }}>
+        {props.message}
+      </div>
+    </div>
+  );
+};
+
+export default Toast;
diff --git a/web/src/core/Operations/parameterOperations.ts b/web/src/core/Operations/parameterOperations.ts
index f502da6..91fe415 100644
--- a/web/src/core/Operations/parameterOperations.ts
+++ b/web/src/core/Operations/parameterOperations.ts
@@ -121,3 +121,24 @@ export const changeTimeStep = (
     null,
   ];
 };
+
+export const changeParameter = (
+  scenario: UnitCommitmentScenario,
+  key: string,
+  valueStr: string,
+): [UnitCommitmentScenario, ValidationError | null] => {
+  const value = parseFloat(valueStr);
+  if (isNaN(value)) {
+    return [scenario, { message: `Invalid value: ${valueStr}` }];
+  }
+  return [
+    {
+      ...scenario,
+      Parameters: {
+        ...scenario.Parameters,
+        [key]: value,
+      },
+    },
+    null,
+  ];
+};