diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 48c00fe..c275c57 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,11 +18,6 @@ jobs:
         image: mongo:7
         ports:
           - 27017:27017
-        options: >-
-          --health-cmd "mongosh --eval 'db.adminCommand({ ping: 1 })'"
-          --health-interval 10s
-          --health-timeout 5s
-          --health-retries 5
     env:
       MONGODB_URI: mongodb://127.0.0.1:27017/bloglist
       DEV_MONGODB_URI: mongodb://127.0.0.1:27017/bloglist-dev
@@ -42,6 +37,17 @@ jobs:
       - name: Install dependencies
         run: npm ci
 
+      - name: Wait for MongoDB
+        run: |
+          for i in {1..30}; do
+            if node -e "const net=require('node:net'); const socket=net.createConnection(27017,'127.0.0.1'); socket.on('connect',()=>{socket.end();process.exit(0)}); socket.on('error',()=>process.exit(1));"; then
+              exit 0
+            fi
+            sleep 2
+          done
+          echo "MongoDB did not become ready in time"
+          exit 1
+
       - name: Lint
         run: npm run lint
 
diff --git a/part4/bloglist/app.js b/part4/bloglist/app.js
index e6863cb..f48de4d 100644
--- a/part4/bloglist/app.js
+++ b/part4/bloglist/app.js
@@ -1,10 +1,10 @@
 const express = require("express");
-const mongoose = require("mongoose");
 const cors = require("cors");
 const path = require("path");
 
 const config = require("./utils/config");
 const logger = require("./utils/logger");
+const { connectToMongo } = require("./utils/mongo");
 const middleware = require("./utils/middleware");
 const blogsRouter = require("./controllers/blogs");
 const usersRouter = require("./controllers/users");
@@ -12,18 +12,7 @@ const loginRouter = require("./controllers/login");
 const testingRouter = require("./controllers/testing");
 
 const app = express();
-
-logger.info("connecting to", config.MONGODB_URI);
-
-mongoose
-  .connect(config.MONGODB_URI, { family: 4, serverSelectionTimeoutMS: 5000 })
-  .then(() => {
-    logger.info("connected to MongoDB");
-  })
-  .catch((error) => {
-    logger.error("error connecting to MongoDB:", error.message);
-    process.exit(1);
-  });
+const mongoConnection = connectToMongo();
 
 app.use(cors());
 app.use(express.json());
@@ -50,4 +39,4 @@ app.get("/{*path}", (req, res) => {
 app.use(middleware.unknownEndpoint);
 app.use(middleware.errorHandler);
 
-module.exports = app;
+module.exports = { app, mongoConnection };
diff --git a/part4/bloglist/index.js b/part4/bloglist/index.js
index 00946c8..e25c8b2 100644
--- a/part4/bloglist/index.js
+++ b/part4/bloglist/index.js
@@ -1,7 +1,14 @@
-const app = require("./app");
+const { app, mongoConnection } = require("./app");
 const config = require("./utils/config");
 const logger = require("./utils/logger");
 
-app.listen(config.PORT, () => {
-  logger.info(`Server running on port ${config.PORT}`);
-});
+mongoConnection
+  .then(() => {
+    app.listen(config.PORT, () => {
+      logger.info(`Server running on port ${config.PORT}`);
+    });
+  })
+  .catch((error) => {
+    logger.error("error connecting to MongoDB:", error.message);
+    process.exit(1);
+  });
diff --git a/part4/bloglist/tests/blog_api.test.js b/part4/bloglist/tests/blog_api.test.js
index 779993c..85427b8 100644
--- a/part4/bloglist/tests/blog_api.test.js
+++ b/part4/bloglist/tests/blog_api.test.js
@@ -1,10 +1,10 @@
-const { test, describe, after, beforeEach } = require("node:test");
+const { test, describe, before, after, beforeEach } = require("node:test");
 const assert = require("node:assert");
 const mongoose = require("mongoose");
 const supertest = require("supertest");
 const bcrypt = require("bcrypt");
 
-const app = require("../app");
+const { app, mongoConnection } = require("../app");
 const Blog = require("../models/blog");
 const User = require("../models/user");
 const helper = require("./test_helper");
@@ -13,6 +13,10 @@ process.env.SECRET = process.env.SECRET || "testsecret";
 
 const api = supertest(app);
 
+before(async () => {
+  await mongoConnection;
+});
+
 // Helpers
 const loginAndGetToken = async (username, password) => {
   const res = await api
@@ -293,6 +297,7 @@ describe("DELETE /api/blogs/:id authorization", () => {
 });
 
 after(async () => {
+  await mongoConnection.catch(() => null);
   await mongoose.connection.close();
 });
 
diff --git a/part4/bloglist/tests/user_api.test.js b/part4/bloglist/tests/user_api.test.js
index d7c93cb..6cd3153 100644
--- a/part4/bloglist/tests/user_api.test.js
+++ b/part4/bloglist/tests/user_api.test.js
@@ -1,15 +1,19 @@
-const { test, describe, beforeEach, after } = require("node:test");
+const { test, describe, before, beforeEach, after } = require("node:test");
 const assert = require("node:assert");
 const mongoose = require("mongoose");
 const supertest = require("supertest");
 const bcrypt = require("bcrypt");
 
-const app = require("../app");
+const { app, mongoConnection } = require("../app");
 const User = require("../models/user");
 const helper = require("./test_helper");
 
 const api = supertest(app);
 
+before(async () => {
+  await mongoConnection;
+});
+
 describe("user creation", () => {
   beforeEach(async () => {
     await User.deleteMany({});
@@ -139,5 +143,6 @@ describe("users with blogs (4.17)", () => {
 });
 
 after(async () => {
+  await mongoConnection.catch(() => null);
   await mongoose.connection.close();
 });
diff --git a/part4/bloglist/utils/mongo.js b/part4/bloglist/utils/mongo.js
new file mode 100644
index 0000000..eb7c3cb
--- /dev/null
+++ b/part4/bloglist/utils/mongo.js
@@ -0,0 +1,26 @@
+const mongoose = require("mongoose");
+
+const config = require("./config");
+const logger = require("./logger");
+
+let mongoConnection = null;
+
+const connectToMongo = () => {
+  if (!mongoConnection) {
+    logger.info("connecting to", config.MONGODB_URI);
+
+    mongoConnection = mongoose
+      .connect(config.MONGODB_URI, {
+        family: 4,
+        serverSelectionTimeoutMS: 5000,
+      })
+      .then(() => {
+        logger.info("connected to MongoDB");
+        return mongoose.connection;
+      });
+  }
+
+  return mongoConnection;
+};
+
+module.exports = { connectToMongo };