diff --git a/micopay/backend/src/routes/ramp.ts b/micopay/backend/src/routes/ramp.ts
index e473e8e..edb624b 100644
--- a/micopay/backend/src/routes/ramp.ts
+++ b/micopay/backend/src/routes/ramp.ts
@@ -41,6 +41,35 @@ function ensureEtherfuseConfigured() {
   }
 }
 
+/**
+ * order_id is a backend-generated UUID handed to Etherfuse, never guessable —
+ * but nothing previously stopped one authenticated user from polling another
+ * user's order if they learned its ID. This records ownership at creation and
+ * enforces it on every subsequent read (see docs/AUDIT_MOBILE_MAINNET.md,
+ * "IDOR ramp order"). Orders created before this migration have no row here —
+ * fail open for those (log + allow) rather than break in-flight orders.
+ */
+async function recordRampOrderOwner(orderId: string, userId: string): Promise<void> {
+  await db.execute(
+    'INSERT INTO ramp_orders (order_id, user_id) VALUES ($1, $2)',
+    [orderId, userId],
+  );
+}
+
+async function assertRampOrderOwnership(orderId: string, userId: string, request: { log: { warn: (obj: unknown, msg: string) => void } }): Promise<void> {
+  const owner = await db.getOne<{ user_id: string }>(
+    'SELECT user_id FROM ramp_orders WHERE order_id = $1',
+    [orderId],
+  );
+  if (!owner) {
+    request.log.warn({ order_id: orderId, user_id: userId, category: 'ramp' }, '[ramp] Order has no recorded owner (pre-migration) — allowing');
+    return;
+  }
+  if (owner.user_id !== userId) {
+    throw new ForbiddenError('No tienes permiso para ver esta orden');
+  }
+}
+
 export async function rampRoutes(app: FastifyInstance): Promise<void> {
   // Get quote: MXN->CETES (onramp) or CETES->MXN (offramp).
   app.post<{ Body: { type: 'onramp' | 'offramp'; sourceAmount: string } }>(
@@ -114,16 +143,19 @@ export async function rampRoutes(app: FastifyInstance): Promise<void> {
       }
 
       const user = await requireOnboardedUser(request.user.id);
+      const orderId = randomUUID();
 
       try {
         const result = await createOrder({
-          orderId: randomUUID(),
+          orderId,
           quoteId,
           bankAccountId: user.etherfuse_bank_account_id!,
           publicKey: user.stellar_address,
           useAnchor,
         });
 
+        await recordRampOrderOwner(orderId, request.user.id);
+
         return 'offramp' in result ? result.offramp : result.onramp;
       } catch (err: any) {
         throw new UpstreamError(
@@ -141,6 +173,7 @@ export async function rampRoutes(app: FastifyInstance): Promise<void> {
     { preHandler: [authMiddleware] },
     async (request) => {
       const { orderId } = request.params;
+      await assertRampOrderOwnership(orderId, request.user.id, request);
       try {
         const order = await getOrder(orderId);
         return { orderId: order.orderId, status: order.status, type: order.orderType };
@@ -163,6 +196,7 @@ export async function rampRoutes(app: FastifyInstance): Promise<void> {
     { preHandler: [authMiddleware] },
     async (request, reply) => {
       const { orderId } = request.params;
+      await assertRampOrderOwnership(orderId, request.user.id, request);
       try {
         const { status, body } = await regenerateOrderTx(orderId);
         return reply.status(status).send(body ?? {});
diff --git a/micopay/frontend/.env.mainnet b/micopay/frontend/.env.mainnet
index ab131df..08b203c 100644
--- a/micopay/frontend/.env.mainnet
+++ b/micopay/frontend/.env.mainnet
@@ -1,5 +1,10 @@
 # Mainnet APK build — overrides .env base values
-VITE_API_URL=https://micopay-api.onrender.com
+# NOTA: api.micopay.app corre hoy en modo STELLAR_NETWORK=TESTNET (ver
+# docs/AWS_MIGRATION_PLAN_2026-07.md §6, taskdef). Este build de mainnet
+# apunta al mismo dominio porque Render se está apagando y no tiene caso
+# dejarlo ahí — pero hasta que exista un backend real en modo MAINNET,
+# las transacciones de este build seguirán siendo de prueba, no reales.
+VITE_API_URL=https://api.micopay.app
 VITE_STELLAR_NETWORK=PUBLIC
 VITE_HORIZON_URL=https://horizon.stellar.org
 VITE_NETWORK_PASSPHRASE=Public Global Stellar Network ; September 2015
diff --git a/micopay/frontend/.env.testnet b/micopay/frontend/.env.testnet
index a5aef7e..7d82431 100644
--- a/micopay/frontend/.env.testnet
+++ b/micopay/frontend/.env.testnet
@@ -1,5 +1,9 @@
 # Testnet APK build — overrides .env base values
-VITE_API_URL=https://micopay-api.onrender.com
+VITE_API_URL=https://api.micopay.app
+# CETES/Blend trading UI (see docs/AUDIT_MOBILE_MAINNET.md finding B2 — that
+# code path doesn't move real user funds yet). Enabled here because testnet
+# builds are internal/demo builds; keep this UNSET in .env.mainnet/.env.production.
+VITE_ENABLE_DEFI_TRADING=true
 VITE_STELLAR_NETWORK=TESTNET
 VITE_ESCROW_CONTRACT_ID=CB4M5777YFQWKGDUULCX5W6PXEDJSJARDTMH4VV6FXC4W4UPANALO3HZ
 VITE_MXNE_CONTRACT_ID=CDLZFC3SYJYDZT7K67VZ75HPJVIEUVNIXF47ZG2FB2RMQQVU2HHGCYSC
diff --git a/micopay/sql/migrations/20260702090000_ramp_order_ownership.down.sql b/micopay/sql/migrations/20260702090000_ramp_order_ownership.down.sql
new file mode 100644
index 0000000..f01a322
--- /dev/null
+++ b/micopay/sql/migrations/20260702090000_ramp_order_ownership.down.sql
@@ -0,0 +1 @@
+DROP TABLE IF EXISTS ramp_orders;
diff --git a/micopay/sql/migrations/20260702090000_ramp_order_ownership.up.sql b/micopay/sql/migrations/20260702090000_ramp_order_ownership.up.sql
new file mode 100644
index 0000000..1ca8391
--- /dev/null
+++ b/micopay/sql/migrations/20260702090000_ramp_order_ownership.up.sql
@@ -0,0 +1,12 @@
+-- SEC hardening: /defi/ramp/order/:orderId and its regenerate_tx sibling let
+-- any authenticated user poll ANY orderId (order IDs are backend-generated
+-- UUIDs, never persisted with an owner — see docs/AUDIT_MOBILE_MAINNET.md,
+-- "IDOR ramp order"). This table records who created each order so the route
+-- can enforce ownership going forward.
+CREATE TABLE IF NOT EXISTS ramp_orders (
+  order_id    UUID PRIMARY KEY,
+  user_id     UUID NOT NULL REFERENCES users(id),
+  created_at  TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_ramp_orders_user ON ramp_orders (user_id, created_at DESC);