diff --git a/src/components/AddTransactionForm.astro b/src/components/AddTransactionForm.astro
index 64123be..5c4c25f 100644
--- a/src/components/AddTransactionForm.astro
+++ b/src/components/AddTransactionForm.astro
@@ -1,51 +1,281 @@
 ---
-// This component needs client-side JS for the toggle
+// This component handles both creating and editing transactions
 ---
 <section class="add-transaction-section">
-     <button
+    <button
         id="toggle-form-btn"
         class="toggle-form-btn"
         aria-expanded="false"
         aria-controls="add-transaction-form"
-     >
+    >
         Add Transaction +
     </button>
-    <form id="add-transaction-form" class="collapsible-form collapsed">
-        <h4>New Transaction</h4>
+    <form id="add-transaction-form" class="collapsible-form collapsed" novalidate>
+        <h4 id="form-title">New Transaction</h4>
+        <div id="form-error" class="error-message hidden"></div>
+        <input type="hidden" id="txn-id" name="id">
         <div class="form-group">
             <label for="txn-date">Date</label>
             <input type="date" id="txn-date" name="date" required>
         </div>
         <div class="form-group">
             <label for="txn-description">Description</label>
-            <input type="text" id="txn-description" name="description" required placeholder="e.g. Groceries">
+            <input type="text" id="txn-description" name="description" required minlength="2" maxlength="100" placeholder="e.g. Groceries">
         </div>
         <div class="form-group">
             <label for="txn-amount">Amount</label>
             <input type="number" id="txn-amount" name="amount" step="0.01" required placeholder="e.g. -25.50 or 1200.00">
+            <small class="help-text">Use negative numbers for expenses (e.g., -50.00)</small>
+        </div>
+        <div class="button-group">
+            <button type="submit" id="submit-btn" class="form-submit-btn">Save Transaction</button>
+            <button type="button" id="cancel-btn" class="cancel-btn hidden">Cancel</button>
         </div>
-        <!-- In a real app, prevent default and use JS to submit -->
-        <button type="submit">Save</button>
     </form>
 </section>
 
-<script>
-    // Script to handle the collapsible form toggle
-    const toggleBtn = document.getElementById('toggle-form-btn');
-    const form = document.getElementById('add-transaction-form');
+<style>
+.error-message {
+    background-color: #f8d7da;
+    border: 1px solid #f5c6cb;
+    color: #721c24;
+    padding: 8px 12px;
+    margin-bottom: 15px;
+    border-radius: 4px;
+    font-size: 0.9em;
+}
+.hidden {
+    display: none;
+}
+.help-text {
+    color: #666;
+    font-size: 0.8em;
+    margin-top: 4px;
+    display: block;
+}
+.button-group {
+    display: flex;
+    gap: 10px;
+    margin-top: 15px;
+}
+.cancel-btn {
+    background-color: #6c757d;
+    color: white;
+    padding: 8px 15px;
+    border: none;
+    border-radius: 3px;
+    cursor: pointer;
+}
+.cancel-btn:hover {
+    background-color: #5a6268;
+}
+.form-submit-btn.loading {
+    background-color: #ccc;
+    cursor: not-allowed;
+}
+</style>
 
+<script>
+    // --- DOM Elements ---
+    const toggleBtn = document.getElementById('toggle-form-btn');
+    const form = document.getElementById('add-transaction-form') as HTMLFormElement;
+    const formTitle = document.getElementById('form-title');
+    const errorDiv = document.getElementById('form-error');
+    const accountSelect = document.getElementById('account-select') as HTMLSelectElement;
+    const cancelBtn = document.getElementById('cancel-btn');
+    const submitBtn = document.getElementById('submit-btn');
+    const txnIdInput = document.getElementById('txn-id') as HTMLInputElement;
+    const dateInput = document.getElementById('txn-date') as HTMLInputElement;
+
+    let isEditMode = false;
+    let isSubmitting = false;
+
+    // Set default date to today
+    if (dateInput) {
+        dateInput.value = new Date().toISOString().split('T')[0];
+    }
+
+    // --- Helper Functions ---
+    function showError(message: string) {
+        if (errorDiv) {
+            errorDiv.textContent = message;
+            errorDiv.classList.remove('hidden');
+        }
+    }
+
+    function hideError() {
+        if (errorDiv) {
+            errorDiv.classList.add('hidden');
+        }
+    }
+
+    function clearForm() {
+        if (form) {
+            form.reset();
+            // Reset date to today
+            if (dateInput) {
+                dateInput.value = new Date().toISOString().split('T')[0];
+            }
+            // Reset edit mode
+            setEditMode(false);
+            // Clear any errors
+            hideError();
+        }
+    }
+
+    function setEditMode(enabled: boolean) {
+        isEditMode = enabled;
+        if (formTitle) formTitle.textContent = enabled ? 'Edit Transaction' : 'New Transaction';
+        if (submitBtn) submitBtn.textContent = enabled ? 'Update Transaction' : 'Save Transaction';
+        if (cancelBtn) cancelBtn.classList.toggle('hidden', !enabled);
+        if (toggleBtn) toggleBtn.classList.toggle('hidden', enabled);
+    }
+
+    function setLoading(enabled: boolean) {
+        isSubmitting = enabled;
+        if (submitBtn) {
+            const button = submitBtn as HTMLButtonElement;
+            button.classList.toggle('loading', enabled);
+            button.disabled = enabled;
+        }
+    }
+
+    function validateForm() {
+        if (!form) return null;
+        
+        const formData = new FormData(form);
+        const errors: string[] = [];
+
+        // Check required fields
+        const description = formData.get('description') as string;
+        const amount = formData.get('amount');
+        const date = formData.get('date');
+
+        if (!description || description.trim().length < 2) {
+            errors.push('Description must be at least 2 characters long');
+        }
+
+        if (!amount) {
+            errors.push('Amount is required');
+        }
+
+        if (!date) {
+            errors.push('Date is required');
+        }
+
+        return errors.length > 0 ? errors : null;
+    }
+
+    // --- Form Toggle ---
     if (toggleBtn && form) {
         toggleBtn.addEventListener('click', () => {
             const isExpanded = toggleBtn.getAttribute('aria-expanded') === 'true';
             toggleBtn.setAttribute('aria-expanded', String(!isExpanded));
             form.classList.toggle('collapsed');
             toggleBtn.textContent = isExpanded ? 'Add Transaction +' : 'Hide Form -';
-            // Optional: Focus first input when opening
             if (!isExpanded) {
                 form.querySelector('input')?.focus();
             }
+            hideError();
         });
-    } else {
-        console.error("Toggle button or form not found");
     }
+
+    // Cancel button handler
+    if (cancelBtn) {
+        cancelBtn.addEventListener('click', () => {
+            clearForm();
+            form?.classList.add('collapsed');
+        });
+    }
+
+    // --- Form Submission ---
+    if (form) {
+        form.addEventListener('submit', async (e) => {
+            e.preventDefault();
+            hideError();
+
+            if (isSubmitting) return;
+
+            // Validate form
+            const errors = validateForm();
+            if (errors) {
+                showError(errors.join('. '));
+                return;
+            }
+
+            setLoading(true);
+
+            try {
+                const formData = new FormData(form);
+                const currentAccountId = accountSelect?.value;
+
+                if (!currentAccountId) {
+                    throw new Error('No account selected');
+                }
+
+                const amount = parseFloat(formData.get('amount') as string);
+                const transaction = {
+                    accountId: currentAccountId,
+                    date: formData.get('date'),
+                    description: (formData.get('description') as string).trim(),
+                    amount: amount
+                };
+
+                const transactionId = formData.get('id');
+                const method = transactionId ? 'PUT' : 'POST';
+                const url = transactionId 
+                    ? `/api/transactions/${transactionId}`
+                    : '/api/transactions';
+
+                const response = await fetch(url, {
+                    method,
+                    headers: {
+                        'Content-Type': 'application/json'
+                    },
+                    body: JSON.stringify(transaction)
+                });
+
+                if (!response.ok) {
+                    const error = await response.json();
+                    throw new Error(error.error || `Failed to ${isEditMode ? 'update' : 'create'} transaction`);
+                }
+
+                // Transaction saved successfully
+                const savedTransaction = await response.json();
+
+                // Update UI
+                const eventName = isEditMode ? 'transactionUpdated' : 'transactionCreated';
+                const event = new CustomEvent(eventName, {
+                    detail: { transaction: savedTransaction }
+                });
+                document.dispatchEvent(event);
+
+                // Clear and collapse form
+                clearForm();
+                form.classList.add('collapsed');
+
+            } catch (error) {
+                showError(error instanceof Error ? error.message : 'An unexpected error occurred');
+            } finally {
+                setLoading(false);
+            }
+        });
+    }
+
+    // --- Edit Transaction Handler ---
+    document.addEventListener('editTransaction', ((event: CustomEvent) => {
+        const transaction = event.detail.transaction;
+        if (!form || !transaction) return;
+
+        // Populate form
+        txnIdInput.value = transaction.id;
+        if (dateInput) dateInput.value = transaction.date;
+        (form.querySelector('#txn-description') as HTMLInputElement).value = transaction.description;
+        (form.querySelector('#txn-amount') as HTMLInputElement).value = transaction.amount.toString();
+
+        // Show form in edit mode
+        setEditMode(true);
+        form.classList.remove('collapsed');
+        form.querySelector('input')?.focus();
+    }) as EventListener);
 </script>
\ No newline at end of file
diff --git a/src/components/TransactionTable.astro b/src/components/TransactionTable.astro
index f62b66b..98b7589 100644
--- a/src/components/TransactionTable.astro
+++ b/src/components/TransactionTable.astro
@@ -11,9 +11,9 @@ const { transactions } = Astro.props;
 // Sort transactions by date descending for display
 const sortedTransactions = [...transactions].sort((a, b) => new Date(b.date).getTime() - new Date(a.date).getTime());
 ---
-<section class="transaction-list">
+<section class="transaction-list" id="transaction-section">
     <table id="transaction-table">
-         <thead>
+        <thead>
             <tr>
                 <th>Date</th>
                 <th>Description</th>
@@ -30,8 +30,8 @@ const sortedTransactions = [...transactions].sort((a, b) => new Date(b.date).get
                         {formatCurrency(txn.amount)}
                     </td>
                     <td>
-                        <button class="action-btn edit-btn" title="Edit transaction (not implemented)">Edit</button>
-                        <button class="action-btn delete-btn" title="Delete transaction (not implemented)">Delete</button>
+                        <button class="action-btn edit-btn" title="Edit transaction">Edit</button>
+                        <button class="action-btn delete-btn" title="Delete transaction">Delete</button>
                     </td>
                 </tr>
             ))}
diff --git a/src/pages/api/transactions/[id]/index.ts b/src/pages/api/transactions/[id]/index.ts
index 8efd606..dc9665b 100644
--- a/src/pages/api/transactions/[id]/index.ts
+++ b/src/pages/api/transactions/[id]/index.ts
@@ -6,10 +6,13 @@ export const PUT: APIRoute = async ({ request, params }) => {
   const { id } = params;
 
   if (!id) {
-    return new Response(JSON.stringify({ error: "Transaction ID is required" }), {
-      status: 400,
-      headers: { "Content-Type": "application/json" },
-    });
+    return new Response(
+      JSON.stringify({ error: "Transaction ID is required" }),
+      {
+        status: 400,
+        headers: { "Content-Type": "application/json" },
+      }
+    );
   }
 
   try {
@@ -65,10 +68,13 @@ export const DELETE: APIRoute = async ({ params }) => {
   const { id } = params;
 
   if (!id) {
-    return new Response(JSON.stringify({ error: "Transaction ID is required" }), {
-      status: 400,
-      headers: { "Content-Type": "application/json" },
-    });
+    return new Response(
+      JSON.stringify({ error: "Transaction ID is required" }),
+      {
+        status: 400,
+        headers: { "Content-Type": "application/json" },
+      }
+    );
   }
 
   const transactionIndex = transactions.findIndex((t) => t.id === id);
diff --git a/src/pages/index.astro b/src/pages/index.astro
index dcf9acd..10b6aac 100644
--- a/src/pages/index.astro
+++ b/src/pages/index.astro
@@ -16,93 +16,244 @@ const initialAccount: Account = accounts[0] || {
     last4: '0000',
     balance: 0
 };
-const initialTransactions: Transaction[] = [];
+
+// Fetch initial transactions if we have an account
+let initialTransactions: Transaction[] = [];
+if (initialAccount.id) {
+    const transactionsResponse = await fetch(`http://localhost:4321/api/accounts/${initialAccount.id}/transactions`);
+    initialTransactions = await transactionsResponse.json();
+}
 ---
 <BaseLayout title="Bank Transactions Dashboard">
-	<div class="dashboard-layout">
-		<Sidebar accounts={accounts} initialAccount={initialAccount} />
-		<MainContent account={initialAccount} transactions={initialTransactions} />
-	</div>
+    <div class="dashboard-layout">
+        <Sidebar accounts={accounts} initialAccount={initialAccount} />
+        <MainContent account={initialAccount} transactions={initialTransactions} />
+    </div>
 </BaseLayout>
 
-<script define:vars={{ allAccounts: accounts, allTransactions: initialTransactions }}>
-    // Client-side script to handle account switching and updating the UI
-
+<script>
     // --- DOM Elements ---
     const accountSelect = document.getElementById('account-select');
     const currentAccountNameSpan = document.getElementById('current-account-name');
     const accountBalanceSpan = document.getElementById('account-balance');
     const transactionTableBody = document.getElementById('transaction-table-body');
 
-    // --- Helper Functions (mirror utils.ts for client-side use) ---
+    // --- Helper Functions ---
     function formatCurrency(amount) {
         return new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' }).format(amount);
     }
 
     function formatDate(dateString) {
-        const date = new Date(dateString + 'T00:00:00'); // Ensure local date
+        const date = new Date(dateString + 'T00:00:00');
         return new Intl.DateTimeFormat('en-US', { year: 'numeric', month: 'short', day: 'numeric' }).format(date);
     }
 
+    async function fetchAccountTransactions(accountId) {
+        try {
+            const response = await fetch(`/api/accounts/${accountId}/transactions`);
+            if (!response.ok) throw new Error('Failed to fetch transactions');
+            return await response.json();
+        } catch (error) {
+            console.error('Error fetching transactions:', error);
+            return [];
+        }
+    }
+
+    async function fetchAccountDetails(accountId) {
+        try {
+            const response = await fetch(`/api/accounts/${accountId}`);
+            if (!response.ok) throw new Error('Failed to fetch account details');
+            return await response.json();
+        } catch (error) {
+            console.error('Error fetching account:', error);
+            return null;
+        }
+    }
+
     // --- Update UI Function ---
-    function updateUIForAccount(accountId) {
-        console.log("Updating UI for account:", accountId); // Debug log
+    async function updateUIForAccount(accountId) {
+        console.log("Updating UI for account:", accountId);
 
-        const selectedAccount = allAccounts.find(acc => acc.id === accountId);
-        const accountTransactions = allTransactions
-            .filter(txn => txn.accountId === accountId)
-            .sort((a, b) => new Date(b.date).getTime() - new Date(a.date).getTime()); // Sort desc
+        const transactionSection = document.getElementById('transaction-section');
+        if (transactionSection) {
+            transactionSection.classList.add('loading');
+        }
 
-        if (!selectedAccount || !transactionTableBody || !currentAccountNameSpan || !accountBalanceSpan) {
-            console.error("Required UI elements not found!");
+        try {
+            // Fetch latest account details and transactions
+            const [account, transactions] = await Promise.all([
+                fetchAccountDetails(accountId),
+                fetchAccountTransactions(accountId)
+            ]);
+
+            if (!account || !transactionTableBody || !currentAccountNameSpan || !accountBalanceSpan) {
+                console.error("Required data or UI elements not found!");
+                return;
+            }
+
+            // Update header
+            currentAccountNameSpan.textContent = `${account.name} (***${account.last4})`;
+
+            // Update summary
+            accountBalanceSpan.textContent = formatCurrency(account.balance);
+
+            // Update table
+            updateTransactionTable(transactions);
+        } catch (error) {
+            console.error('Error updating UI:', error);
+            if (transactionTableBody) {
+                transactionTableBody.innerHTML = `
+                    <tr>
+                        <td colspan="4" style="text-align: center; color: #dc3545;">
+                            Failed to load transactions. Please try again.
+                        </td>
+                    </tr>`;
+            }
+        } finally {
+            if (transactionSection) {
+                transactionSection.classList.remove('loading');
+            }
+        }
+    }
+
+    function updateTransactionTable(transactions) {
+        if (!transactionTableBody) return;
+
+        const sortedTransactions = [...transactions].sort((a, b) => 
+            new Date(b.date).getTime() - new Date(a.date).getTime()
+        );
+
+        transactionTableBody.innerHTML = '';
+
+        if (sortedTransactions.length === 0) {
+            transactionTableBody.innerHTML = `
+                <tr>
+                    <td colspan="4" style="text-align: center; font-style: italic; color: #777;">
+                        No transactions found for this account.
+                    </td>
+                </tr>`;
             return;
         }
 
-        // Update header
-        currentAccountNameSpan.textContent = `${selectedAccount.name} (***${selectedAccount.last4})`;
+        sortedTransactions.forEach(txn => {
+            const row = document.createElement('tr');
+            row.setAttribute('data-txn-id', txn.id);
+            row.innerHTML = `
+                <td>${formatDate(txn.date)}</td>
+                <td>${txn.description}</td>
+                <td class="amount-col ${txn.amount >= 0 ? 'amount-positive' : 'amount-negative'}">
+                    ${formatCurrency(txn.amount)}
+                </td>
+                <td>
+                    <button class="action-btn edit-btn" title="Edit transaction">Edit</button>
+                    <button class="action-btn delete-btn" title="Delete transaction">Delete</button>
+                </td>
+            `;
+            transactionTableBody.appendChild(row);
+        });
 
-        // Update summary
-        accountBalanceSpan.textContent = formatCurrency(selectedAccount.balance);
+        // Add event listeners for edit and delete buttons
+        setupTransactionButtons();
+    }
 
-        // Update table
-        transactionTableBody.innerHTML = ''; // Clear existing rows
+    // --- Transaction Actions ---
+    async function handleDeleteTransaction(txnId) {
+        if (!confirm('Are you sure you want to delete this transaction?')) {
+            return;
+        }
 
-        if (accountTransactions.length === 0) {
-            transactionTableBody.innerHTML = `<tr><td colspan="4" style="text-align: center; font-style: italic; color: #777;">No transactions found for this account.</td></tr>`;
-        } else {
-            accountTransactions.forEach(txn => {
-                const row = document.createElement('tr');
-                row.setAttribute('data-txn-id', txn.id);
-                row.innerHTML = `
-                    <td>${formatDate(txn.date)}</td>
-                    <td>${txn.description}</td>
-                    <td class="amount-col ${txn.amount >= 0 ? 'amount-positive' : 'amount-negative'}">
-                        ${formatCurrency(txn.amount)}
-                    </td>
-                    <td>
-                        <button class="action-btn edit-btn" title="Edit transaction (not implemented)">Edit</button>
-                        <button class="action-btn delete-btn" title="Delete transaction (not implemented)">Delete</button>
-                    </td>
-                `;
-                transactionTableBody.appendChild(row);
+        const transactionSection = document.getElementById('transaction-section');
+        if (transactionSection) {
+            transactionSection.classList.add('loading');
+        }
+
+        try {
+            const response = await fetch(`/api/transactions/${txnId}`, {
+                method: 'DELETE'
             });
+
+            if (!response.ok) {
+                const error = await response.json();
+                throw new Error(error.error || 'Failed to delete transaction');
+            }
+
+            // Refresh the current account view
+            const currentAccountId = accountSelect?.value;
+            if (currentAccountId) {
+                await updateUIForAccount(currentAccountId);
+            }
+        } catch (error) {
+            alert(error instanceof Error ? error.message : 'Failed to delete transaction');
+        } finally {
+            if (transactionSection) {
+                transactionSection.classList.remove('loading');
+            }
         }
     }
 
-    // --- Event Listener ---
-    if (accountSelect) {
-        accountSelect.addEventListener('change', (event) => {
-            const selectedAccountId = event.target.value;
-            updateUIForAccount(selectedAccountId);
-        });
-    } else {
-        console.error("Account select element not found");
+    async function handleEditTransaction(txnId) {
+        try {
+            // Find transaction in current transactions list
+            const currentAccountId = accountSelect?.value;
+            const transactions = await fetchAccountTransactions(currentAccountId);
+            const transaction = transactions.find(t => t.id === txnId);
+            
+            if (!transaction) {
+                throw new Error('Transaction not found');
+            }
+
+            // Trigger edit mode in form
+            document.dispatchEvent(new CustomEvent('editTransaction', {
+                detail: { transaction }
+            }));
+
+        } catch (error) {
+            alert(error instanceof Error ? error.message : 'Failed to load transaction for editing');
+        }
     }
 
-    // --- Initial Load (Optional but good practice) ---
-    // The page already renders the initial state server-side,
-    // so no need to call updateUIForAccount() immediately unless
-    // there's a chance the JS loads before initial render completes fully.
-    // console.log("Account switcher script loaded.");
+    function setupTransactionButtons() {
+        const transactionRows = transactionTableBody?.querySelectorAll('tr[data-txn-id]');
+        transactionRows?.forEach(row => {
+            const txnId = row.getAttribute('data-txn-id');
+            if (!txnId) return;
 
+            // Delete button handler
+            const deleteBtn = row.querySelector('.delete-btn');
+            deleteBtn?.addEventListener('click', () => handleDeleteTransaction(txnId));
+
+            // Edit button handler
+            const editBtn = row.querySelector('.edit-btn');
+            editBtn?.addEventListener('click', () => handleEditTransaction(txnId));
+        });
+    }
+
+    // --- Event Listeners ---
+    if (accountSelect) {
+        accountSelect.addEventListener('change', async (event) => {
+            const selectedAccountId = event.target.value;
+            await updateUIForAccount(selectedAccountId);
+        });
+    }
+
+    // Listen for transaction events
+    document.addEventListener('transactionCreated', async (event) => {
+        const currentAccountId = accountSelect?.value;
+        if (currentAccountId) {
+            await updateUIForAccount(currentAccountId);
+        }
+    });
+
+    document.addEventListener('transactionUpdated', async (event) => {
+        const currentAccountId = accountSelect?.value;
+        if (currentAccountId) {
+            await updateUIForAccount(currentAccountId);
+        }
+    });
+
+    // Initial load with transactions if available
+    const initialAccountId = accountSelect?.value;
+    if (initialAccountId) {
+        updateUIForAccount(initialAccountId);
+    }
 </script>
\ No newline at end of file
diff --git a/src/styles/global.css b/src/styles/global.css
index 80a8eef..08e85f1 100644
--- a/src/styles/global.css
+++ b/src/styles/global.css
@@ -232,3 +232,48 @@ tbody tr:hover {
     padding: 20px;
   }
 }
+
+/* Loading States */
+.loading {
+  opacity: 0.6;
+  pointer-events: none;
+  position: relative;
+}
+
+.loading::after {
+  content: "";
+  position: absolute;
+  top: 50%;
+  left: 50%;
+  width: 1.5em;
+  height: 1.5em;
+  margin: -0.75em 0 0 -0.75em;
+  border: 3px solid rgba(0, 123, 255, 0.2);
+  border-top-color: #007bff;
+  border-radius: 50%;
+  animation: spinner 0.6s linear infinite;
+}
+
+@keyframes spinner {
+  to {
+    transform: rotate(360deg);
+  }
+}
+
+.form-submit-btn {
+  position: relative;
+  min-width: 100px;
+}
+
+.form-submit-btn.loading {
+  padding-right: 35px;
+}
+
+.form-submit-btn.loading::after {
+  width: 1em;
+  height: 1em;
+  margin: -0.5em 0 0 0;
+  left: auto;
+  right: 10px;
+  border-width: 2px;
+}