diff --git a/src/app/api/functions/csvReadWrite.ts b/src/app/api/functions/csvReadWrite.ts
new file mode 100644
index 0000000..6683182
--- /dev/null
+++ b/src/app/api/functions/csvReadWrite.ts
@@ -0,0 +1,98 @@
+import path from "path";
+import fs from "fs";
+import csv from "csv-parser";
+
+export type User = {
+  name: string;
+  email: string;
+  password: string;
+};
+
+/**
+ * @returns {array} - Array of Objects containing user data
+ */
+export async function readUserCsv(): Promise<User[]> {
+  return new Promise((resolve, reject) => {
+    // Dynamic CSV location generation
+    let csvPath = path.dirname(__dirname); // /login
+    csvPath = path.dirname(csvPath); // /api
+    csvPath = path.dirname(csvPath); // /app
+    csvPath = path.dirname(csvPath); // /src
+    csvPath = path.dirname(csvPath); // /[project]
+    csvPath = path.dirname(csvPath); // /termor-tracker
+    csvPath = path.join(csvPath, "src", "databases", "Users.csv");
+
+    // Forms array for user data
+    let results: User[] = [];
+    // Reads data and adds it to results
+    fs.createReadStream(csvPath)
+      .pipe(csv())
+      .on("data", (data) => results.push(data))
+      .on("end", () => {
+        resolve(results);
+      })
+      .on("error", (error) => {
+        reject(error);
+      });
+  });
+}
+
+export function findUserByEmail(users: User[], email: string): User | undefined {
+  return users.find((user) => user.email === email);
+}
+
+export async function passwordStrengthCheck(password: string): Promise<string> {
+  if (password.length < 8) {
+    return "short";
+  } else if (password.length > 16) {
+    return "long";
+  }
+  const lowercaseRegex = /[a-z]/;
+  const uppercaseRegex = /[A-Z]/;
+  const digitRegex = /\d/;
+  const specialCharRegex = /[!@#$%^&*]/;
+  if (!lowercaseRegex.test(password)) {
+    return "no lower";
+  } else if (!uppercaseRegex.test(password)) {
+    return "no upper";
+  } else if (!digitRegex.test(password)) {
+    return "no digit";
+  } else if (!specialCharRegex.test(password)) {
+    return "no special";
+  } else {
+    return "secure";
+  }
+  return "end of function";
+}
+
+/**
+ * Writes User objects to the Users.csv file
+ * @param users {User[]} Array of User objects to write to the CSV file
+ * @returns {Promise<void>}
+ */
+export async function writeUserCsv(users: User[]): Promise<void> {
+  return new Promise((resolve, reject) => {
+    // Dynamic CSV location generation
+    let csvPath = path.dirname(__dirname); // /login
+    csvPath = path.dirname(csvPath); // /api
+    csvPath = path.dirname(csvPath); // /app
+    csvPath = path.dirname(csvPath); // /src
+    csvPath = path.dirname(csvPath); // /[project]
+    csvPath = path.dirname(csvPath); // /termor-tracker
+    csvPath = path.join(csvPath, "src", "databases", "Users.csv");
+
+    // Prepare CSV data as a string
+    const headers = "name,email,password"; // CSV headers
+    const rows = users.map((user) => `${user.name},${user.email},${user.password}`);
+    const csvData = `${headers}\n${rows.join("\n")}`;
+
+    // Write data to the file
+    fs.writeFile(csvPath, csvData, (error) => {
+      if (error) {
+        reject(error); // Reject promise on error
+      } else {
+        resolve(); // Resolve the promise if successful
+      }
+    });
+  });
+}
\ No newline at end of file
diff --git a/src/app/api/login/route.ts b/src/app/api/login/route.ts
index 7f0c0c3..0bd9cb0 100644
--- a/src/app/api/login/route.ts
+++ b/src/app/api/login/route.ts
@@ -1,47 +1,5 @@
 import { NextResponse } from "next/server";
-import path from "path";
-import fs from "fs";
-import csv from "csv-parser";
-
-type User = {
-  name: string;
-  email: string;
-  password: string;
-}
-
-/**
- * @returns {array} - Array of Objects containing user data
- */
-async function readUserCsv(): Promise<User[]>{
-  return new Promise((resolve, reject) => {
-  // Dynamic csv location generation
-  let csvPath = path.dirname(__dirname); // /login
-  csvPath = path.dirname(csvPath); // /api
-  csvPath = path.dirname(csvPath); // /app
-  csvPath = path.dirname(csvPath); // /src
-  csvPath = path.dirname(csvPath); // /[project] // ? not sure why this dirfolder is here...
-  csvPath = path.dirname(csvPath); // /termor-tracker
-  csvPath = path.join(csvPath,"src","databases","Users.csv");
-  //Forms array for user data
-  let results : User[] = [];
-
-  //Reads data and adds it to results
-  fs.createReadStream(csvPath)
-    .pipe(csv())
-    .on("data", (data) => results.push(data))
-    .on("end", () => {
-      resolve(results)
-    })
-    .on("error", (error) => {
-      reject(error)
-    })
-
-  });
-}
-
-function findUserByEmail(users: User[], email: string): User | undefined {
-  return users.find((user) => user.email === email);
-}
+import {User, readUserCsv, findUserByEmail} from "../functions/csvReadWrite"
 
 export async function POST(request: Request) {
   try {
diff --git a/src/app/api/signup/route.ts b/src/app/api/signup/route.ts
index e023903..062b1b9 100644
--- a/src/app/api/signup/route.ts
+++ b/src/app/api/signup/route.ts
@@ -1,17 +1,54 @@
 import { NextResponse } from "next/server";
+import {User, readUserCsv, writeUserCsv, findUserByEmail, passwordStrengthCheck} from "../functions/csvReadWrite"
 
 export async function POST(request: Request) {
   try {
     const body = await request.json(); // Parse incoming JSON data
-    const { name, email, password } = body;
+    const {name, email, password } = body;
+    console.log("Signin API received data"); 
+
+    const userData = await readUserCsv();
+
+    console.log(userData)
+    console.log("Name:", name); // ! remove
+    console.log("Email:", email); // ! remove
+    console.log("Password:", password);// ! remove
+
+    const foundUser = findUserByEmail(userData,email)
+
+    if (foundUser) {
+      console.log("Email already in the system")
+      return NextResponse.json({ message: "Sorry, this email is already in use" }, { status: 409 });
+    }
+
+    const passwordCheckResult = await passwordStrengthCheck(password)
+    
+    if (passwordCheckResult === "short"){
+      return NextResponse.json({ message: "Your password is shorter than 8 characters" }, { status: 400 });
+    } else if (passwordCheckResult === "long"){
+      return NextResponse.json({ message: "Your password is longer than 16 characters" }, { status: 400 });
+    } else if (passwordCheckResult === "no lower"){
+      return NextResponse.json({ message: "Your password must contain a lowercase letters" }, { status: 400 });
+    } else if (passwordCheckResult === "no upper"){
+      return NextResponse.json({ message: "Your password must contain a uppercase letters" }, { status: 400 });
+    } else if (passwordCheckResult === "no digit"){
+      return NextResponse.json({ message: "Your password must contain a number" }, { status: 400 });
+    } else if (passwordCheckResult === "no special"){
+      return NextResponse.json({ message: "Your password must contain a special character (!@#$%^&*)" }, { status: 400 });
+    } else if (passwordCheckResult === "end of function"){
+      return NextResponse.json({ message: "Password check script failure" }, { status: 500 });
+    } else {
+      try {
+        userData.push(body)
+        await writeUserCsv(userData)
+        return NextResponse.json({ message: "Account Created" }, { status: 201 });
+      } catch(error) {
+        console.error("Error in writting :", error);
+      return NextResponse.json({ message: "Internal Server Error" }, { status: 500 });
+      }
+    }
 
-    console.log("Signup API received data:");
-    console.log("Name:", name);
-    console.log("Email:", email);
-    console.log("Password:", password);
 
-    // For now, just respond back with a success message
-    return NextResponse.json({ message: "Signup successful!" }, { status: 201 });
   } catch (error) {
     console.error("Error in signup endpoint:", error);
     return NextResponse.json({ message: "Internal Server Error" }, { status: 500 });
diff --git a/src/components/AuthModal.tsx b/src/components/AuthModal.tsx
index 367975c..b46522d 100644
--- a/src/components/AuthModal.tsx
+++ b/src/components/AuthModal.tsx
@@ -20,6 +20,7 @@ export default function AuthModal({ isOpen, onClose }: AuthModalProps) { //AuthM
   const [isLogin, setIsLogin] = useState<boolean>(true);
   const modalRef = useRef<HTMLDivElement>(null);
   const [isFailed, setIsFailed] = useState<boolean>(false);
+  const [failMessage, setFailMessage] = useState<boolean>(false);
 /*
     useState is a React Hook that declares state variables in a functional component. It returns a two-element array
     The state variable (isLogin) : Represents the current state value (e.g., true initially). This is the value you can use in your component.
@@ -90,8 +91,10 @@ export default function AuthModal({ isOpen, onClose }: AuthModalProps) { //AuthM
       if (res.ok) { //res.ok checks if the response is between 200-299
         console.log("Success!");
         onClose(); // closes UI
-      } else if (res.status === 401){
-        console.log("Incorrect details provided")
+      } else if (res.status >= 400 && res.status <500){
+        const responseBody = await res.json()
+        console.log("4xx error:", responseBody.message)
+        setFailMessage(responseBody.message)
         setIsFailed(true)
       } else{
         console.error("Error:", await res.text()); // logs error with error message sent to console
@@ -104,7 +107,7 @@ export default function AuthModal({ isOpen, onClose }: AuthModalProps) { //AuthM
   return (
     <div className="fixed inset-0 bg-black bg-opacity-70 flex items-center justify-center z-50" onClick={handleOverlayClick}>
       <div ref={modalRef} className="bg-white rounded-lg shadow-lg p-6 w-full max-w-md relative">
-        <button onClick={onClose} className="absolute text-xl top-0 right-2 text-gray-500 hover:text-gray-700" aria-label="Close modal">
+        <button onClick={() => {setIsFailed(false);onClose();}} className="absolute text-xl top-0 right-2 text-gray-500 hover:text-gray-700" aria-label="Close modal">
           ×
         </button>
         <h2 className="text-2xl font-bold text-center mb-4">{isLogin ? "Login" : "Sign Up"}</h2>
@@ -143,7 +146,7 @@ export default function AuthModal({ isOpen, onClose }: AuthModalProps) { //AuthM
           <div>
             { isFailed && (
               <div>
-                <label className="block text-sm font-medium text-red-700">Incorrect email or password</label>
+                <label className="block text-sm font-medium text-red-700">{failMessage}</label>
               </div>
             )
             }