diff --git a/data.json b/data.json
index a2c844f..fe3771d 100644
--- a/data.json
+++ b/data.json
@@ -1,121 +1,86 @@
 [
-    {
-    "_id": "682bab8c12155b00101732ce",
-    "message": "Berlin baby",
-    "hearts": 37,
-    "createdAt": "2025-05-19T22:07:08.999Z",
-    "__v": 0
-  },
-  {
-  "_id": "682e53cc4fddf50010bbe739",
-    "message": "My family!",
-    "hearts": 0,
-    "createdAt": "2025-05-22T22:29:32.232Z",
-    "__v": 0
-  },
-  {
-    "_id": "682e4f844fddf50010bbe738",
-    "message": "The smell of coffee in the morning....",
-    "hearts": 23,
-    "createdAt": "2025-05-22T22:11:16.075Z",
-    "__v": 0
-  },
   {
-    "_id": "682e48bf4fddf50010bbe737",
-    "message": "Newly washed bedlinen, kids that sleeps through the night.. FINGERS CROSSED 🤞🏼\n",
-    "hearts": 6,
-    "createdAt": "2025-05-21T21:42:23.862Z",
-  "__v": 0
+    "id": 1,
+    "message": "Today is a beautiful day! 🌞",
+    "hearts": 5,
+    "createdAt": "2025-06-15T10:00:00Z",
+    "category": "Life"
   },
   {
-    "_id": "682e45804fddf50010bbe736",
-    "message": "I am happy that I feel healthy and have energy again",
-    "hearts": 13,
-    "createdAt": "2025-05-21T21:28:32.196Z",
-    "__v": 0
+    "id": 2,
+    "message": "I made progress on my project!",
+    "hearts": 10,
+    "createdAt": "2025-06-14T15:30:00Z",
+    "category": "Work"
   },
   {
-    "_id": "682e23fecf615800105107aa",
-    "message": "cold beer",
+    "id": 3,
+    "message": "I had the best ramen today 🍜",
     "hearts": 2,
-    "createdAt": "2025-05-21T19:05:34.113Z",
-    "__v": 0
+    "createdAt": "2025-06-13T20:00:00Z",
+    "category": "Food"
   },
   {
-    "_id": "682e22aecf615800105107a9",
-    "message": "My friend is visiting this weekend! <3",
-    "hearts": 6,
-    "createdAt": "2025-05-21T18:59:58.121Z",
-    "__v": 0
-  },
-  {
-    "_id": "682cec1b17487d0010a298b6",
-    "message": "A god joke: \nWhy did the scarecrow win an award?\nBecause he was outstanding in his field!",
-    "hearts": 12,
-    "createdAt": "2025-05-20T20:54:51.082Z",
-  "__v": 0
+    "id": 4,
+    "message": "I made progress on my project!",
+    "hearts": 10,
+    "createdAt": "2025-06-14T15:30:00Z",
+    "category": "Work"
   },
   {
-    "_id": "682cebbe17487d0010a298b5",
-    "message": "Tacos and tequila🌮🍹",
+    "id": 5,
+    "message": "I had the best ramen today 🍜",
     "hearts": 2,
-    "createdAt": "2025-05-19T20:53:18.899Z",
-    "__v": 0
+    "createdAt": "2025-06-13T20:00:00Z",
+    "category": "Food"
   },
   {
-    "_id": "682ceb5617487d0010a298b4",
-    "message": "Netflix and late night ice-cream🍦",
-    "hearts": 1,
-    "createdAt": "2025-05-18T20:51:34.494Z",
-    "__v": 0
+    "id": 6,
+    "message": "I learned something new today! 📚",
+    "hearts": 8,
+    "createdAt": "2025-06-12T12:00:00Z",
+    "category": "Education"
   },
   {
-    "_id": "682c99ba3bff2d0010f5d44e",
-    "message": "Summer is coming...",
-    "hearts": 2,
-    "createdAt": "2025-05-20T15:03:22.379Z",
-  "__v": 0
-  },
-  {
-    "_id": "682c706c951f7a0017130024",
-    "message": "Exercise? I thought you said extra fries! 🍟😂",
-    "hearts": 14,
-    "createdAt": "2025-05-20T12:07:08.185Z",
-    "__v": 0
+    "id": 7,
+    "message": "I went for a long walk in the park 🌳",
+    "hearts": 3,
+    "createdAt": "2025-06-11T08:30:00Z",
+    "category": "Health"
   },
   {
-    "_id": "682c6fe1951f7a0017130023",
-    "message": "I’m on a seafood diet. I see food, and I eat it.",
-    "hearts": 4,
-    "createdAt": "2025-05-20T12:04:49.978Z",
-    "__v": 0
+    "id": 8,
+    "message": "I had a great time with friends last night! 🎉",
+    "hearts": 12,
+    "createdAt": "2025-06-10T22:00:00Z",
+    "category": "Social"
   },
   {
-    "_id": "682c6f0e951f7a0017130022",
-    "message": "Cute monkeys🐒",
-    "hearts": 2,
-    "createdAt": "2025-05-20T12:01:18.308Z",
-    "__v": 0
+    "id": 9,
+    "message": "I finished reading a fantastic book 📖",
+    "hearts": 6,
+    "createdAt": "2025-06-09T18:45:00Z",
+    "category": "Leisure"
   },
   {
-    "_id": "682c6e65951f7a0017130021",
-    "message": "The weather is nice!",
-    "hearts": 0,
-    "createdAt": "2025-05-20T11:58:29.662Z",
-    "__v": 0
+    "id": 10,
+    "message": "I tried a new recipe and it was delicious! 🍽️",
+    "hearts": 4,
+    "createdAt": "2025-06-08T14:15:00Z",
+    "category": "Food"
   },
   {
-    "_id": "682bfdb4270ca300105af221",
-    "message": "good vibes and good things",
-    "hearts": 3,
-    "createdAt": "2025-05-20T03:57:40.322Z",
-    "__v": 0
+    "id": 11,
+    "message": "I completed a challenging workout today! 💪",
+    "hearts": 7,
+    "createdAt": "2025-06-07T16:00:00Z",
+    "category": "Health"
   },
   {
-    "_id": "682bab8c12155b00101732ce",
-    "message": "Berlin baby",
-    "hearts": 37,
-    "createdAt": "2025-05-19T22:07:08.999Z",
-    "__v": 0
+    "id": 12,
+    "message": "I had a productive day at work! 🖥️",
+    "hearts": 9,
+    "createdAt": "2025-06-06T11:30:00Z",
+    "category": "Work"
   }
-]
\ No newline at end of file
+]
diff --git a/package.json b/package.json
index bf25bb6..fc8a97c 100644
--- a/package.json
+++ b/package.json
@@ -12,8 +12,15 @@
     "@babel/core": "^7.17.9",
     "@babel/node": "^7.16.8",
     "@babel/preset-env": "^7.16.11",
+    "bcrypt": "^6.0.0",
     "cors": "^2.8.5",
-    "express": "^4.17.3",
-    "nodemon": "^3.0.1"
+    "crypto": "^1.0.1",
+    "dotenv": "^17.2.1",
+    "e": "^0.2.33",
+    "express": "^4.21.2",
+    "express-list-endpoints": "^7.1.1",
+    "mongoose": "^8.17.1",
+    "nodemon": "^3.0.1",
+    "xpress": "^2.4.6"
   }
 }
diff --git a/server.js b/server.js
index f47771b..7f58648 100644
--- a/server.js
+++ b/server.js
@@ -1,22 +1,296 @@
-import cors from "cors"
-import express from "express"
+import cors from "cors";
+import express from "express";
+import listEndpoints from "express-list-endpoints";
+import fs, { access } from "fs";
+import mongoose from "mongoose";
+import dotenv from "dotenv";
+import bcrypt from "bcrypt";
+import crypto from "crypto";
+
+// Load environment variables from .env file
+// This allows  to set environment variables like PORT and MONGO_URL
+// in a .env file for local development
+dotenv.config();
 
 // Defines the port the app will run on. Defaults to 8080, but can be overridden
 // when starting the server. Example command to overwrite PORT env variable value:
 // PORT=9000 npm start
-const port = process.env.PORT || 8080
-const app = express()
+const port = process.env.PORT || 8080;
+const app = express();
 
 // Add middlewares to enable cors and json body parsing
-app.use(cors())
-app.use(express.json())
+app.use(cors({
+  origin: ["http://localhost:5174", "https://happythoughtsappbydanu.netlify.app"], // add your deployed FE origin here later
+  methods: ["GET", "POST", "PATCH", "DELETE", "OPTIONS"],
+  allowedHeaders: ["Content-Type", "Authorization"],
+  // credentials: true, // only if you ever use cookies
+}));
+app.use(express.json());
+
+//let thoughts = JSON.parse(fs.readFileSync('./data.json'));
+
+const mongoUrl =
+  process.env.MONGO_URL || "mongodb://localhost:27017/happythoughts";
+
+// Connect to MongoDB
+mongoose.connect(mongoUrl, { useNewUrlParser: true, useUnifiedTopology: true });
+mongoose.Promise = Promise;
+
+// ----- Mongoose Schema -----
+const thoughtSchema = new mongoose.Schema({
+  message: {
+    type: String,
+    required: [true, "Message is required"],
+    minlength: [5, "Message must be at least 5 characters"],
+    maxlength: [140, "Message must be max 140 characters"],
+  },
+  hearts: {
+    type: Number,
+    default: 0,
+  },
+  category: {
+    type: String,
+    default: "General",
+  },
+  createdBy: { 
+    type: String, 
+    required: true },
+  createdAt: {
+    type: Date,
+    default: () => new Date(),
+  },
+});
+
+const Thought = mongoose.model("Thought", thoughtSchema);
+//User model
+const userSchema = new mongoose.Schema({
+  username: {
+    type: String,
+    required: [true, "Username is required"],
+    unique: true,
+    minlength: [3, "Username must be at least 3 characters"],
+    maxlength: [20, "Username must be max 20 characters"],
+  },
+  password: {
+    type: String,
+    required: [true, "Password is required"],
+    minlength: [6, "Password must be at least 6 characters"],
+  },
+  accessToken: {
+    type: String,
+    default: () => crypto.randomBytes(16).toString("hex"),
+  },
+});
+
+const User = mongoose.model("User", userSchema);
+
+// ----- Middleware for authentication -----
+const authenticateUser = async (req, res, next) => {
+  const raw = req.header("Authorization") || "";
+  // accept "Bearer <token>" OR raw "<token>"
+  const accessToken = raw.startsWith("Bearer ") ? raw.slice(7) : raw;
+
+  try {
+    const user = await User.findOne({ accessToken });
+    if (user) {
+      req.user = user;
+      next();
+    } else {
+      res.status(401).json({ message: "Please log in" });
+    }
+  } catch (err) {
+    res.status(403).json({ message: "Access denied" });
+  }
+};
 
-// Start defining your routes here
+// ----- User Registration -----
+app.post("/register", async (req, res) => {
+  try {
+    const { username, password } = req.body;
+
+    if (password.length < 5) {
+      return res
+        .status(400)
+        .json({ message: "Password must be at least 5 characters long" });
+    }
+
+    const salt = bcrypt.genSaltSync();
+    const hashedPassword = bcrypt.hashSync(password, salt);
+
+    const newUser = await new User({
+      username,
+      password: hashedPassword,
+    }).save();
+
+    res.status(201).json({
+      username: newUser.username,
+      accessToken: newUser.accessToken,
+    });
+  } catch (err) {
+    if (err.code === 11000) {
+      res.status(400).json({ message: "That username already exists" });
+    } else {
+      res.status(500).json({ message: "Internal server error", error: err });
+    }
+  }
+});
+// ----- User Login -----
+app.post("/login", async (req, res) => {
+  const { username, password } = req.body;
+  const user = await User.findOne({ username });
+
+  if (!user) {
+    return res
+      .status(400)
+      .json({ message: "Username or password is incorrect" });
+  }
+
+  if (bcrypt.compareSync(password, user.password)) {
+    res.json({
+      username: user.username,
+      accessToken: user.accessToken,
+    });
+  } else {
+    res.status(400).json({ message: "Username or password is incorrect" });
+  }
+});
+
+// API Docs----- Routes -----
 app.get("/", (req, res) => {
-  res.send("Hello Technigo!")
-})
+  res.json({
+    message: "Welcome to the Happy Thoughts API 💬",
+    endpoints: listEndpoints(app),
+  });
+});
+
+// Get all thoughts (with filtering, sorting, pagination)
+app.get("/thoughts", async (req, res) => {
+  try {
+    const { heartsMin, category, sortBy, page, limit } = req.query;
+    let query = {};
+
+    if (heartsMin) {
+      query.hearts = { $gte: parseInt(heartsMin) };
+    }
+    if (category) {
+      query.category = category;
+    }
+
+    let sort = {};
+    if (sortBy === "hearts") sort.hearts = -1;
+    if (sortBy === "date") sort.createdAt = -1;
+
+    const pageInt = parseInt(page) || 1;
+    const limitInt = parseInt(limit) || 20;
+    const skip = (pageInt - 1) * limitInt;
+
+    const thoughts = await Thought.find(query)
+      .sort(sort)
+      .skip(skip)
+      .limit(limitInt);
+
+    res.json({
+      page: pageInt,
+      results: thoughts,
+    });
+  } catch (err) {
+    res.status(500).json({ error: "Failed to fetch thoughts" });
+  }
+});
+
+// Get single thought
+app.get("/thoughts/:id", async (req, res) => {
+  try {
+    const thought = await Thought.findById(req.params.id);
+    if (!thought) {
+      return res.status(404).json({ error: "Thought not found" });
+    }
+    res.json(thought);
+  } catch {
+    res.status(400).json({ error: "Invalid ID" });
+  }
+});
+
+// Create new thought (authenticated)
+app.post("/thoughts", authenticateUser, async (req, res) => {
+  try {
+    const { message, category } = req.body;
+    const newThought = new Thought({
+      message,
+      category,
+      createdBy: req.user.username,
+    });
+
+    const savedThought = await newThought.save();
+    res.status(201).json(savedThought);
+  } catch (err) {
+    res.status(400).json({ message: "Could not save thought", error: err });
+  }
+});
+
+// Update a thought
+app.patch("/thoughts/:id", authenticateUser, async (req, res) => {
+  try {
+    const thought = await Thought.findById(req.params.id);
+
+    if (!thought) {
+      return res.status(404).json({ message: "Thought not found" });
+    }
+
+    if (thought.createdBy !== req.user.username) {
+      return res
+        .status(403)
+        .json({ message: "Not allowed to edit this thought" });
+    }
+
+    thought.message = req.body.message || thought.message;
+    await thought.save();
+    res.json(thought);
+  } catch (err) {
+    res.status(400).json({ message: "Could not update thought", error: err });
+  }
+});
+
+// Delete a thought
+app.delete("/thoughts/:id", authenticateUser, async (req, res) => {
+  try {
+    const thought = await Thought.findById(req.params.id);
+
+    if (!thought) {
+      return res.status(404).json({ message: "Thought not found" });
+    }
+
+    if (thought.createdBy !== req.user.username) {
+      return res
+        .status(403)
+        .json({ message: "Not allowed to delete this thought" });
+    }
+
+    await thought.deleteOne();
+    res.json({ message: "Thought deleted successfully" });
+  } catch (err) {
+    res.status(400).json({ message: "Could not delete thought", error: err });
+  }
+});
+
+// Like a thought
+app.post("/thoughts/:id/like", async (req, res) => {
+  try {
+    const thought = await Thought.findByIdAndUpdate(
+      req.params.id,
+      { $inc: { hearts: 1 } },
+      { new: true }
+    );
+    if (!thought) {
+      return res.status(404).json({ error: "Thought not found" });
+    }
+    res.json(thought);
+  } catch (err) {
+    res.status(400).json({ error: err.message });
+  }
+});
 
 // Start the server
 app.listen(port, () => {
-  console.log(`Server running on http://localhost:${port}`)
-})
+  console.log(`Server running on http://localhost:${port}`);
+});