diff --git a/frontend/src/api/campaigns.ts b/frontend/src/api/campaigns.ts
index b815033..e7795c2 100644
--- a/frontend/src/api/campaigns.ts
+++ b/frontend/src/api/campaigns.ts
@@ -34,6 +34,9 @@ export interface Campaign {
   start_date: string | null;
   scheduled_at: string | null;
   completed_at: string | null;
+  approved_by: string | null;
+  approved_at: string | null;
+  rejection_reason: string | null;
   target_platform: string | null;
   tags: string[];
   created_at: string | null;
@@ -65,7 +68,6 @@ export interface CampaignSummary {
 export interface CampaignCreatePayload {
   name: string;
   description?: string;
-  start_date?: string;  // ISO date YYYY-MM-DD — campaign won't activate before this
   type?: string;
   threat_actor_id?: string;
   target_platform?: string;
@@ -80,6 +82,35 @@ export interface AddTestPayload {
   phase?: string;
 }
 
+export type ModificationRequestAction = "add_test" | "remove_test";
+export type ModificationRequestStatus = "pending" | "approved" | "rejected";
+
+export interface CampaignModificationRequest {
+  id: string;
+  campaign_id: string;
+  campaign_name: string | null;
+  requested_by: string | null;
+  action: ModificationRequestAction;
+  test_id: string | null;
+  test_name: string | null;
+  order_index: number | null;
+  phase: string | null;
+  justification: string;
+  status: ModificationRequestStatus;
+  reviewed_by: string | null;
+  reviewed_at: string | null;
+  review_notes: string | null;
+  created_at: string | null;
+}
+
+export interface CampaignTimelineEntry {
+  id: string;
+  action: string;
+  user_id: string | null;
+  timestamp: string;
+  details: Record<string, unknown>;
+}
+
 // ── API Functions ───────────────────────────────────────────────────
 
 /** List campaigns with optional filters. */
@@ -247,3 +278,93 @@ export async function getCampaignHistory(campaignId: string): Promise<{
   const { data } = await client.get(`/campaigns/${campaignId}/history`);
   return data;
 }
+
+// ── Approval workflow ──────────────────────────────────────────────
+
+/** Submit a draft campaign into the manager's approval queue. */
+export async function submitCampaignForApproval(campaignId: string): Promise<Campaign> {
+  const { data } = await client.post<Campaign>(`/campaigns/${campaignId}/submit`);
+  return data;
+}
+
+/** Manager approves a pending campaign, fixing its start date. */
+export async function approveCampaign(campaignId: string, startDate: string): Promise<Campaign> {
+  const { data } = await client.post<Campaign>(`/campaigns/${campaignId}/approve`, {
+    start_date: startDate,
+  });
+  return data;
+}
+
+/** Manager rejects a pending campaign with a mandatory reason. */
+export async function rejectCampaign(campaignId: string, reason: string): Promise<Campaign> {
+  const { data } = await client.post<Campaign>(`/campaigns/${campaignId}/reject`, { reason });
+  return data;
+}
+
+// ── Modification requests ───────────────────────────────────────────
+
+/** File a request to add/remove a test on an active campaign. */
+export async function createModificationRequest(
+  campaignId: string,
+  payload: {
+    action: ModificationRequestAction;
+    test_id: string;
+    justification: string;
+    order_index?: number;
+    phase?: string;
+  },
+): Promise<CampaignModificationRequest> {
+  const { data } = await client.post<CampaignModificationRequest>(
+    `/campaigns/${campaignId}/modification-requests`,
+    payload,
+  );
+  return data;
+}
+
+/** List modification requests filed against a specific campaign. */
+export async function listCampaignModificationRequests(
+  campaignId: string,
+): Promise<CampaignModificationRequest[]> {
+  const { data } = await client.get<CampaignModificationRequest[]>(
+    `/campaigns/${campaignId}/modification-requests`,
+  );
+  return data;
+}
+
+/** Manager's global queue of modification requests awaiting review. */
+export async function listPendingModificationRequests(): Promise<CampaignModificationRequest[]> {
+  const { data } = await client.get<CampaignModificationRequest[]>(
+    "/campaigns/modification-requests/pending",
+  );
+  return data;
+}
+
+/** Manager approves a modification request — the test change is applied now. */
+export async function approveModificationRequest(
+  requestId: string,
+): Promise<CampaignModificationRequest> {
+  const { data } = await client.post<CampaignModificationRequest>(
+    `/campaigns/modification-requests/${requestId}/approve`,
+  );
+  return data;
+}
+
+/** Manager rejects a modification request with mandatory review notes. */
+export async function rejectModificationRequest(
+  requestId: string,
+  reviewNotes: string,
+): Promise<CampaignModificationRequest> {
+  const { data } = await client.post<CampaignModificationRequest>(
+    `/campaigns/modification-requests/${requestId}/reject`,
+    { review_notes: reviewNotes },
+  );
+  return data;
+}
+
+// ── Timeline ─────────────────────────────────────────────────────────
+
+/** Get the audit-log timeline for a campaign. */
+export async function getCampaignTimeline(campaignId: string): Promise<CampaignTimelineEntry[]> {
+  const { data } = await client.get<CampaignTimelineEntry[]>(`/campaigns/${campaignId}/timeline`);
+  return data;
+}