diff --git a/frontend/src/CreateCampaign.jsx b/frontend/src/CreateCampaign.jsx
index f33078e9..6d29b9ee 100644
--- a/frontend/src/CreateCampaign.jsx
+++ b/frontend/src/CreateCampaign.jsx
@@ -4,6 +4,7 @@ import { apiUrl, getStellarNetwork } from './config';
 import { logSafeEvent } from './lib/safeAnalytics';
 import { initializeCampaignContract, getWalletAddress, isWalletConnected } from './stellar';
 import TransactionStatus from './components/TransactionStatus';
+import { validateCampaignForm } from './lib/validateCampaignForm';
 
 const MAX_IMAGE_SIZE_BYTES = 2 * 1024 * 1024;
 const ALLOWED_IMAGE_TYPES = ['image/png', 'image/jpeg', 'image/jpg'];
@@ -40,6 +41,8 @@ export default function CreateCampaign({ onCampaignCreated, campaigns = [], stan
   const [success, setSuccess] = useState('');
   const [deploymentStatus, setDeploymentStatus] = useState('');
   const [txHash, setTxHash] = useState('');
+  const [touched, setTouched] = useState({});
+  const [submitAttempted, setSubmitAttempted] = useState(false);
   const headingId = useId();
   const nameId = useId();
   const descId = useId();
@@ -61,7 +64,32 @@ export default function CreateCampaign({ onCampaignCreated, campaigns = [], stan
     : '';
   const effectiveApiKey = apiKeyInput || storedApiKey;
 
-  const isValid = name.trim().length >= 3 && name.trim().length <= 80;
+  const fieldErrors = validateCampaignForm(
+    {
+      name,
+      rewardPerAction,
+      maxParticipants,
+      rewardToken,
+      contractId: contractIdInput,
+      startDate,
+      endDate,
+    },
+    { isEditMode },
+  );
+  const isValid = Object.keys(fieldErrors).length === 0;
+  const markTouched = (field) => setTouched((prev) => ({ ...prev, [field]: true }));
+  const visibleError = (field) =>
+    (touched[field] || submitAttempted) && fieldErrors[field] ? fieldErrors[field] : '';
+  const errorProps = (field, inputId) =>
+    visibleError(field)
+      ? { 'aria-invalid': true, 'aria-describedby': `${inputId}-error` }
+      : {};
+  const renderFieldError = (field, inputId) =>
+    visibleError(field) ? (
+      <small id={`${inputId}-error`} className="create-campaign-field-error" role="alert">
+        {visibleError(field)}
+      </small>
+    ) : null;
 
   const loadCampaignForEdit = (campaignId) => {
     setSelectedId(campaignId);
@@ -131,7 +159,11 @@ export default function CreateCampaign({ onCampaignCreated, campaigns = [], stan
 
   const handleSubmit = async (event) => {
     event.preventDefault();
-    if (!isValid) return;
+    setSubmitAttempted(true);
+    if (!isValid) {
+      setError('Please fix the highlighted fields before submitting.');
+      return;
+    }
     if (!effectiveApiKey) {
       setError('Admin API key is required. It is stored in session only.');
       return;
@@ -252,6 +284,8 @@ export default function CreateCampaign({ onCampaignCreated, campaigns = [], stan
       setDeployOnChain(false);
       setImageFile(null);
       setImagePreview('');
+      setTouched({});
+      setSubmitAttempted(false);
 
       if (onCampaignCreated) {
         onCampaignCreated(campaign);
@@ -332,7 +366,10 @@ export default function CreateCampaign({ onCampaignCreated, campaigns = [], stan
             minLength={3}
             maxLength={80}
             onChange={(e) => setName(e.target.value)}
+            onBlur={() => markTouched('name')}
+            {...errorProps('name', nameId)}
           />
+          {renderFieldError('name', nameId)}
           <small className="create-campaign-hint">3–80 characters</small>
         </div>
 
@@ -363,7 +400,10 @@ export default function CreateCampaign({ onCampaignCreated, campaigns = [], stan
             value={rewardToken}
             disabled={isSubmitting}
             onChange={(e) => setRewardToken(e.target.value)}
+            onBlur={() => markTouched('rewardToken')}
+            {...errorProps('rewardToken', rewardTokenId)}
           />
+          {renderFieldError('rewardToken', rewardTokenId)}
           <small className="create-campaign-hint">
             Stellar asset contract address. Leave empty to default to native XLM.
           </small>
@@ -383,7 +423,10 @@ export default function CreateCampaign({ onCampaignCreated, campaigns = [], stan
             value={rewardPerAction}
             disabled={isSubmitting}
             onChange={(e) => setRewardPerAction(e.target.value)}
+            onBlur={() => markTouched('rewardPerAction')}
+            {...errorProps('rewardPerAction', rewardId)}
           />
+          {renderFieldError('rewardPerAction', rewardId)}
           <small className="create-campaign-hint">
             Points or token units awarded per qualifying action.
           </small>
@@ -403,7 +446,10 @@ export default function CreateCampaign({ onCampaignCreated, campaigns = [], stan
             value={maxParticipants}
             disabled={isSubmitting}
             onChange={(e) => setMaxParticipants(e.target.value)}
+            onBlur={() => markTouched('maxParticipants')}
+            {...errorProps('maxParticipants', maxParticipantsId)}
           />
+          {renderFieldError('maxParticipants', maxParticipantsId)}
           <small className="create-campaign-hint">Set to 0 for unlimited participants.</small>
         </div>
 
@@ -419,7 +465,10 @@ export default function CreateCampaign({ onCampaignCreated, campaigns = [], stan
               value={startDate}
               disabled={isSubmitting}
               onChange={(e) => setStartDate(e.target.value)}
+              onBlur={() => markTouched('startDate')}
+              {...errorProps('startDate', startDateId)}
             />
+            {renderFieldError('startDate', startDateId)}
           </div>
 
           <div className="create-campaign-field">
@@ -433,7 +482,10 @@ export default function CreateCampaign({ onCampaignCreated, campaigns = [], stan
               value={endDate}
               disabled={isSubmitting}
               onChange={(e) => setEndDate(e.target.value)}
+              onBlur={() => markTouched('endDate')}
+              {...errorProps('endDate', endDateId)}
             />
+            {renderFieldError('endDate', endDateId)}
           </div>
         </div>
 
@@ -487,7 +539,10 @@ export default function CreateCampaign({ onCampaignCreated, campaigns = [], stan
             value={contractIdInput}
             disabled={isSubmitting}
             onChange={(e) => setContractIdInput(e.target.value)}
+            onBlur={() => markTouched('contractId')}
+            {...errorProps('contractId', contractIdInputId)}
           />
+          {renderFieldError('contractId', contractIdInputId)}
           <small className="create-campaign-hint">
             Enter a deployed campaign contract ID to link this campaign to on-chain state.
           </small>
@@ -515,7 +570,7 @@ export default function CreateCampaign({ onCampaignCreated, campaigns = [], stan
         <button
           type="submit"
           className="btn btn-primary btn-button"
-          disabled={!isValid || isSubmitting || !effectiveApiKey}
+          disabled={isSubmitting || !effectiveApiKey}
         >
           {isSubmitting
             ? isEditMode
diff --git a/frontend/src/Landing.css b/frontend/src/Landing.css
index 5e5882ee..59f02459 100644
--- a/frontend/src/Landing.css
+++ b/frontend/src/Landing.css
@@ -1659,3 +1659,15 @@
   color: var(--text-muted);
   font-style: italic;
 }
+
+/* Issue #1230: inline client-side validation feedback on the campaign form */
+.create-campaign-field-error {
+  display: block;
+  margin-top: 0.25rem;
+  color: var(--danger);
+  font-size: 0.8125rem;
+}
+
+.create-campaign-input[aria-invalid='true'] {
+  border-color: var(--danger);
+}
diff --git a/frontend/src/lib/validateCampaignForm.js b/frontend/src/lib/validateCampaignForm.js
new file mode 100644
index 00000000..2faaf973
--- /dev/null
+++ b/frontend/src/lib/validateCampaignForm.js
@@ -0,0 +1,63 @@
+// Client-side validation for the CreateCampaign form (issue #1230).
+// Pure function so it can be unit tested without rendering the form.
+
+const STELLAR_CONTRACT_RE = /^C[A-Z2-7]{55}$/;
+
+/**
+ * @param {object} values - raw form values (strings as held in state)
+ * @param {object} [options]
+ * @param {boolean} [options.isEditMode] - skip "end date in the past" for existing campaigns
+ * @param {Date}    [options.now]
+ * @returns {Record<string, string>} map of field -> error message (empty when valid)
+ */
+export function validateCampaignForm(values, { isEditMode = false, now = new Date() } = {}) {
+  const errors = {};
+  const name = (values.name || '').trim();
+
+  if (!name) {
+    errors.name = 'Campaign name is required.';
+  } else if (name.length < 3 || name.length > 80) {
+    errors.name = 'Campaign name must be 3–80 characters.';
+  }
+
+  if (values.rewardPerAction !== '' && values.rewardPerAction != null) {
+    const reward = Number(values.rewardPerAction);
+    if (!Number.isFinite(reward) || reward <= 0) {
+      errors.rewardPerAction = 'Reward amount must be a positive number.';
+    } else if (!Number.isInteger(reward)) {
+      errors.rewardPerAction = 'Reward amount must be a whole number of token units.';
+    }
+  }
+
+  if (values.maxParticipants !== '' && values.maxParticipants != null) {
+    const max = Number(values.maxParticipants);
+    if (!Number.isInteger(max) || max < 0) {
+      errors.maxParticipants = 'Max participants must be a whole number (0 = unlimited).';
+    }
+  }
+
+  const token = (values.rewardToken || '').trim();
+  if (token && !STELLAR_CONTRACT_RE.test(token)) {
+    errors.rewardToken = 'Reward token must be a Stellar contract address (C…, 56 characters).';
+  }
+
+  const contractId = (values.contractId || '').trim();
+  if (contractId && !STELLAR_CONTRACT_RE.test(contractId)) {
+    errors.contractId = 'Contract ID must be a Stellar contract address (C…, 56 characters).';
+  }
+
+  const start = values.startDate ? new Date(values.startDate) : null;
+  const end = values.endDate ? new Date(values.endDate) : null;
+  if (start && Number.isNaN(start.getTime())) errors.startDate = 'Start date is invalid.';
+  if (end && Number.isNaN(end.getTime())) {
+    errors.endDate = 'End date is invalid.';
+  } else if (end) {
+    if (!isEditMode && end.getTime() <= now.getTime()) {
+      errors.endDate = 'End date must be in the future.';
+    } else if (start && !errors.startDate && end.getTime() <= start.getTime()) {
+      errors.endDate = 'End date must be after the start date.';
+    }
+  }
+
+  return errors;
+}
diff --git a/frontend/src/lib/validateCampaignForm.test.js b/frontend/src/lib/validateCampaignForm.test.js
new file mode 100644
index 00000000..95403eaa
--- /dev/null
+++ b/frontend/src/lib/validateCampaignForm.test.js
@@ -0,0 +1,63 @@
+import { describe, expect, it } from 'vitest';
+import { validateCampaignForm } from './validateCampaignForm';
+
+const NOW = new Date('2026-01-01T00:00:00Z');
+const CONTRACT = `C${'A'.repeat(55)}`;
+const valid = {
+  name: 'Onboarding Rewards',
+  rewardPerAction: '10',
+  maxParticipants: '0',
+  rewardToken: '',
+  contractId: '',
+  startDate: '2026-02-01T00:00',
+  endDate: '2026-03-01T00:00',
+};
+const run = (overrides, opts = {}) => validateCampaignForm({ ...valid, ...overrides }, { now: NOW, ...opts });
+
+describe('validateCampaignForm', () => {
+  it('accepts a valid form', () => {
+    expect(run({})).toEqual({});
+  });
+
+  it('accepts empty optional fields', () => {
+    expect(run({ rewardPerAction: '', maxParticipants: '', startDate: '', endDate: '' })).toEqual({});
+  });
+
+  it('requires a 3–80 character name', () => {
+    expect(run({ name: '   ' }).name).toMatch(/required/);
+    expect(run({ name: 'ab' }).name).toMatch(/3–80/);
+    expect(run({ name: 'x'.repeat(81) }).name).toMatch(/3–80/);
+  });
+
+  it('rejects zero, negative, fractional and non-numeric token amounts', () => {
+    expect(run({ rewardPerAction: '0' }).rewardPerAction).toMatch(/positive/);
+    expect(run({ rewardPerAction: '-5' }).rewardPerAction).toMatch(/positive/);
+    expect(run({ rewardPerAction: 'abc' }).rewardPerAction).toMatch(/positive/);
+    expect(run({ rewardPerAction: '1.5' }).rewardPerAction).toMatch(/whole/);
+  });
+
+  it('rejects negative or fractional max participants', () => {
+    expect(run({ maxParticipants: '-1' }).maxParticipants).toBeDefined();
+    expect(run({ maxParticipants: '2.5' }).maxParticipants).toBeDefined();
+  });
+
+  it('validates Stellar contract addresses', () => {
+    expect(run({ rewardToken: 'GABC' }).rewardToken).toBeDefined();
+    expect(run({ contractId: 'nope' }).contractId).toBeDefined();
+    expect(run({ rewardToken: CONTRACT, contractId: CONTRACT })).toEqual({});
+  });
+
+  it('rejects end dates in the past when creating', () => {
+    expect(run({ startDate: '', endDate: '2025-06-01T00:00' }).endDate).toMatch(/future/);
+  });
+
+  it('allows past end dates when editing an existing campaign', () => {
+    expect(run({ startDate: '', endDate: '2025-06-01T00:00' }, { isEditMode: true })).toEqual({});
+  });
+
+  it('requires end date after start date', () => {
+    expect(run({ startDate: '2026-03-01T00:00', endDate: '2026-02-01T00:00' }).endDate).toMatch(
+      /after the start/,
+    );
+  });
+});