diff --git a/.env.example b/.env.example
new file mode 100644
index 0000000..22b2a81
--- /dev/null
+++ b/.env.example
@@ -0,0 +1,16 @@
+# Authentication
+AUTH_SECRET=          # Generate with: openssl rand -base64 32
+
+# Stripe
+STRIPE_SECRET_KEY=    # sk_live_... or sk_test_...
+STRIPE_WEBHOOK_SECRET= # whsec_...
+STRIPE_STARTER_PRICE_ID=price_1SzJUlR8i0An4Wz7gZeYgzBY
+STRIPE_PRO_PRICE_ID=price_1SzJVWR8i0An4Wz755hBrxzn
+
+# Database (optional — defaults to agentlens/agentlens/agentlens)
+POSTGRES_USER=agentlens
+POSTGRES_PASSWORD=
+POSTGRES_DB=agentlens
+
+# Email (optional — email features disabled if not set)
+EMAIL_PASSWORD=
diff --git a/apps/web/src/app/api/traces/route.ts b/apps/web/src/app/api/traces/route.ts
index d582a7f..1b2d218 100644
--- a/apps/web/src/app/api/traces/route.ts
+++ b/apps/web/src/app/api/traces/route.ts
@@ -241,9 +241,14 @@ export async function POST(request: NextRequest) {
       for (const trace of body.traces) {
         const existing = await tx.trace.findUnique({
           where: { id: trace.id },
-          select: { id: true },
+          select: { id: true, userId: true },
         });
 
+        // Security: prevent cross-user trace overwrite
+        if (existing && existing.userId !== userId) {
+          continue; // skip traces owned by other users
+        }
+
         const traceData = {
           name: trace.name,
           sessionId: trace.sessionId,
diff --git a/docker-compose.yml b/docker-compose.yml
index 39d67f1..eb16b44 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -8,13 +8,13 @@ services:
     environment:
       - NODE_ENV=production
       - REDIS_URL=redis://redis:6379
-      - DATABASE_URL=postgresql://agentlens:agentlens@postgres:5432/agentlens
-      - AUTH_SECRET=Ge0Gh6bObko0Gdrzv+l0qKHgvut3M7Av8mDFQG9fYzs=
+      - DATABASE_URL=postgresql://${POSTGRES_USER:-agentlens}:${POSTGRES_PASSWORD:-agentlens}@postgres:5432/${POSTGRES_DB:-agentlens}
+      - AUTH_SECRET=${AUTH_SECRET}
       - AUTH_TRUST_HOST=true
       - STRIPE_SECRET_KEY=${STRIPE_SECRET_KEY:-}
-      - STRIPE_WEBHOOK_SECRET=whsec_ZGT3JCrEK6GWP3cIMvYfrfLplZ3rMn0m
-      - STRIPE_STARTER_PRICE_ID=price_1SzJUlR8i0An4Wz7gZeYgzBY
-      - STRIPE_PRO_PRICE_ID=price_1SzJVWR8i0An4Wz755hBrxzn
+      - STRIPE_WEBHOOK_SECRET=${STRIPE_WEBHOOK_SECRET}
+      - STRIPE_STARTER_PRICE_ID=${STRIPE_STARTER_PRICE_ID:-price_1SzJUlR8i0An4Wz7gZeYgzBY}
+      - STRIPE_PRO_PRICE_ID=${STRIPE_PRO_PRICE_ID:-price_1SzJVWR8i0An4Wz755hBrxzn}
       - EMAIL_PASSWORD=${EMAIL_PASSWORD:-}
     depends_on:
       redis:
@@ -45,9 +45,9 @@ services:
   postgres:
     image: postgres:16-alpine
     environment:
-      - POSTGRES_USER=agentlens
-      - POSTGRES_PASSWORD=agentlens
-      - POSTGRES_DB=agentlens
+      - POSTGRES_USER=${POSTGRES_USER:-agentlens}
+      - POSTGRES_PASSWORD=${POSTGRES_PASSWORD:-agentlens}
+      - POSTGRES_DB=${POSTGRES_DB:-agentlens}
     volumes:
       - agentlens_postgres_data:/var/lib/postgresql/data
     healthcheck:
@@ -72,7 +72,7 @@ services:
       target: builder
     command: npx prisma db push --schema=packages/database/prisma/schema.prisma --skip-generate
     environment:
-      - DATABASE_URL=postgresql://agentlens:agentlens@postgres:5432/agentlens
+      - DATABASE_URL=postgresql://${POSTGRES_USER:-agentlens}:${POSTGRES_PASSWORD:-agentlens}@postgres:5432/${POSTGRES_DB:-agentlens}
     depends_on:
       postgres:
         condition: service_healthy