diff --git a/docker-compose.yml b/docker-compose.yml
index 7cbbaac..8912da5 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -51,6 +51,7 @@ services:
       - DATABASE_URL=postgresql://linkforty:secret_password_prod@postgres-prod:5432/linkforty_prod?sslmode=disable
       - REDIS_URL=redis://redis-prod:6379
       - PORT=3000
+      - TRUST_PROXY=1
     depends_on:
       - postgres-prod
       - redis-prod
@@ -88,6 +89,7 @@ services:
       - DATABASE_URL=postgresql://linkforty:secret_password_sandbox@postgres-sandbox:5432/linkforty_sandbox?sslmode=disable
       - REDIS_URL=redis://redis-sandbox:6379
       - PORT=3001
+      - TRUST_PROXY=1
     depends_on:
       - postgres-sandbox
       - redis-sandbox
diff --git a/src/lib/fingerprint.test.ts b/src/lib/fingerprint.test.ts
index af3f75a..846d4be 100644
--- a/src/lib/fingerprint.test.ts
+++ b/src/lib/fingerprint.test.ts
@@ -442,6 +442,10 @@ describe('recordInstallEvent', () => {
       pid: 'recommend_user',
       u: 'abc',
     });
+    expect(result.deepLinkData.customParameters).toEqual({
+      pid: 'recommend_user',
+      u: 'abc',
+    });
     expect(result.deepLinkData.clickQueryParameters).toEqual({ u: 'abc' });
   });
 });
diff --git a/src/lib/fingerprint.ts b/src/lib/fingerprint.ts
index b5a7055..c0da968 100644
--- a/src/lib/fingerprint.ts
+++ b/src/lib/fingerprint.ts
@@ -691,6 +691,8 @@ export async function recordInstallEvent(
         utmParameters: link.utm_parameters,
         targetingRules: link.targeting_rules,
         deepLinkParameters,
+        // Backward-compatible alias for older SDKs expecting `customParameters`.
+        customParameters: deepLinkParameters,
         clickQueryParameters: clickQueryParams,
         clickedAt: match.clickedAt,
         confidenceScore: match.confidenceScore,