diff --git a/back-end/Dockerfile.back b/back-end/Dockerfile.back
index 8b28269..9079939 100644
--- a/back-end/Dockerfile.back
+++ b/back-end/Dockerfile.back
@@ -5,12 +5,12 @@ FROM node:22-alpine
 WORKDIR /usr/src/back
 
 # Environment declaration variables
-ARG NODE_ENV="dev"
-ARG DB_HOST="postgres"
-ARG DB_NAME="briques"
-ARG DB_USER="briques_db"
-ARG DB_PASSWORD="briques_password"
-ARG DB_PORT=5432
+ENV NODE_ENV="dev"
+ENV DB_HOST="briques_postgres"
+ENV DB_NAME="briques_db"
+ENV DB_USER="briques_llm"
+ENV DB_PASSWORD="briques_password_2025"
+ENV DB_PORT=5432
 
 COPY package.json ./
 
@@ -40,4 +40,5 @@ RUN chmod -R u=rwx,g=,o= ./
 EXPOSE 3000
 
 # Start app
-CMD ["pm2", "start", "dist/app.js", "--no-daemon"]
+CMD ["npm", "run", "startonly"]
+#CMD ["pm2", "start", "dist/app.js", "--no-daemon"]
diff --git a/back-end/package.json b/back-end/package.json
index b728e0d..7c8cdf5 100644
--- a/back-end/package.json
+++ b/back-end/package.json
@@ -14,6 +14,7 @@
     "description": "",
     "devDependencies": {
         "@types/express": "^5.0.0",
+        "@types/pg": "^8.11.10",
         "globals": "^15.11.0",
         "typescript": "^5.6.3"
     },
diff --git a/back-end/src/app.ts b/back-end/src/app.ts
index bd7c445..dee7341 100644
--- a/back-end/src/app.ts
+++ b/back-end/src/app.ts
@@ -1,9 +1,12 @@
 import express from 'express';
-const app = express();
-const port = 3000;
+import db from './db';
 
-app.get('/', (req, res) => {
-    res.send('Hello World!');
+const app = express();
+const port = process.env.PORT ?? 3000;
+
+app.get('/', async (_req, res) => {
+  const message = await db.example_request();
+  res.send(message);
 });
 
 app.listen(port, () => {
diff --git a/back-end/src/db/db_client.ts b/back-end/src/db/db_client.ts
new file mode 100644
index 0000000..52d29ca
--- /dev/null
+++ b/back-end/src/db/db_client.ts
@@ -0,0 +1,23 @@
+import pg from 'pg';
+
+const db_user = process.env.DB_USER ?? "admin";
+const db_password = process.env.DB_PASSWORD ?? "admin";
+const db_name = process.env.DB_NAME ?? "briques";
+const db_host = process.env.DB_HOST ?? "localhost";
+const db_port = parseInt(process.env.DB_PORT ?? "5432");
+
+console.log("=== DB CONFIG ===");
+console.log(`DB_USER:\t\t${db_user}`);
+console.log(`DB_PASSWORD:\t${db_user}`);
+console.log(`DB_NAME:\t\t${db_name}`);
+console.log(`DB_HOST:\t\t${db_host}`);
+console.log(`DB_PORT:\t\t${db_port}`);
+
+
+export const new_client = () => new pg.Client({
+  user: db_user,
+  password: db_password,
+  database: db_name,
+  host: db_host,
+  port: db_port,
+});
diff --git a/back-end/src/db/index.ts b/back-end/src/db/index.ts
new file mode 100644
index 0000000..934d4dd
--- /dev/null
+++ b/back-end/src/db/index.ts
@@ -0,0 +1,16 @@
+import { new_client } from './db_client';
+
+async function example_request() {
+  const client = new_client();
+  await client.connect();
+
+  const res = await client.query('SELECT $1::text as message', ['Hello world!']);
+  const message = res.rows[0].message;  // Hello world!
+  await client.end();
+
+  return message;
+}
+
+export default {
+  example_request,
+};
diff --git a/docker-compose.yml b/docker-compose.yml
index 12c63f9..bf9b6ff 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -10,6 +10,11 @@ services:
       - POSTGRES_PASSWORD=${DB_PASSWORD}
     volumes:
       - ./database:/var/lib/postgresql/data
+
+    networks:
+      - briques-db
+
+
   back:
     hostname: back
     container_name: briques_back
@@ -27,8 +32,21 @@ services:
       - '${NODE_PORT}:3000'
     depends_on:
       - database
+
+    networks:
+      - briques-db
+
   adminer:
     image: adminer
     restart: always
     ports:
       - 8080:8080
+
+    networks:
+      - briques-db
+
+
+networks:
+    briques-db:
+        driver: bridge
+