diff --git a/database/db.go b/database/db.go
index f53f4d7..ded201f 100644
--- a/database/db.go
+++ b/database/db.go
@@ -17,12 +17,12 @@ func InitDatabase() (*sql.DB, error) {
 	password := os.Getenv("PG_PASSWORD")
 	host := os.Getenv("PG_HOST")
 	connStr := fmt.Sprintf("user=postgres host=%s dbname=relay password=%s sslmode=disable", host, password)
-	db, err := sql.Open("postgres", connStr)
+	DB, err := sql.Open("postgres", connStr)
 	if err != nil {
 		log.Fatal(err)
 	}
 
-	return db, nil
+	return DB, nil
 
 }
 
@@ -44,3 +44,32 @@ func GetUsers(db *sql.DB) ([]string, error) {
 	}
 	return users, err
 }
+
+func CheckUserExists(db *sql.DB, username string) (bool, error) {
+	query := `SELECT COUNT(1) FROM accounts WHERE username= $1`
+
+	var count int
+
+	err := db.QueryRow(query, username).Scan(&count)
+
+	if err != nil {
+		return false, fmt.Errorf("error checking username exists: %v", err)
+	}
+
+	return count > 0, err
+}
+
+func InsertUser(db *sql.DB, username string, passwordHash string) (string, error) {
+	query := `
+    INSERT INTO Accounts (username, password_hash)
+    VALUES ($1, $2)
+    RETURNING user_id;
+  `
+
+	var userId string
+	err := db.QueryRow(query, username, passwordHash).Scan(&userId)
+	if err != nil {
+		return "", fmt.Errorf("error inserting user: %v", err)
+	}
+	return userId, err
+}
diff --git a/go.mod b/go.mod
index bbef2f7..0e43da8 100644
--- a/go.mod
+++ b/go.mod
@@ -6,10 +6,12 @@ require (
 	github.com/gofiber/fiber/v2 v2.52.6
 	github.com/joho/godotenv v1.5.1
 	github.com/lib/pq v1.10.9
+	golang.org/x/crypto v0.32.0
 )
 
 require (
 	github.com/andybalholm/brotli v1.1.0 // indirect
+	github.com/golang-jwt/jwt/v5 v5.2.1 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/klauspost/compress v1.17.9 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
@@ -19,5 +21,5 @@ require (
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
 	github.com/valyala/fasthttp v1.51.0 // indirect
 	github.com/valyala/tcplisten v1.0.0 // indirect
-	golang.org/x/sys v0.28.0 // indirect
+	golang.org/x/sys v0.29.0 // indirect
 )
diff --git a/go.sum b/go.sum
index de0d8d0..1f5110d 100644
--- a/go.sum
+++ b/go.sum
@@ -2,6 +2,8 @@ github.com/andybalholm/brotli v1.1.0 h1:eLKJA0d02Lf0mVpIDgYnqXcUn0GqVmEFny3VuID1
 github.com/andybalholm/brotli v1.1.0/go.mod h1:sms7XGricyQI9K10gOSf56VKKWS4oLer58Q+mhRPtnY=
 github.com/gofiber/fiber/v2 v2.52.6 h1:Rfp+ILPiYSvvVuIPvxrBns+HJp8qGLDnLJawAu27XVI=
 github.com/gofiber/fiber/v2 v2.52.6/go.mod h1:YEcBbO/FB+5M1IZNBP9FO3J9281zgPAreiI1oqg8nDw=
+github.com/golang-jwt/jwt/v5 v5.2.1 h1:OuVbFODueb089Lh128TAcimifWaLhJwVflnrgM17wHk=
+github.com/golang-jwt/jwt/v5 v5.2.1/go.mod h1:pqrtFR0X4osieyHYxtmOUWsAWrfe1Q5UVIyoH402zdk=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
@@ -25,7 +27,13 @@ github.com/valyala/fasthttp v1.51.0 h1:8b30A5JlZ6C7AS81RsWjYMQmrZG6feChmgAolCl1S
 github.com/valyala/fasthttp v1.51.0/go.mod h1:oI2XroL+lI7vdXyYoQk03bXBThfFl2cVdIA3Xl7cH8g=
 github.com/valyala/tcplisten v1.0.0 h1:rBHj/Xf+E1tRGZyWIWwJDiRY0zc1Js+CV5DqwacVSA8=
 github.com/valyala/tcplisten v1.0.0/go.mod h1:T0xQ8SeCZGxckz9qRXTfG43PvQ/mcWh7FwZEA7Ioqkc=
+golang.org/x/crypto v0.14.0 h1:wBqGXzWJW6m1XrIKlAH0Hs1JJ7+9KBwnIO8v66Q9cHc=
+golang.org/x/crypto v0.14.0/go.mod h1:MVFd36DqK4CsrnJYDkBA3VC4m2GkXAM0PvzMCn4JQf4=
+golang.org/x/crypto v0.32.0 h1:euUpcYgM8WcP71gNpTqQCn6rC2t6ULUPiOzfWaXVVfc=
+golang.org/x/crypto v0.32.0/go.mod h1:ZnnJkOaASj8g0AjIduWNlq2NRxL0PlBrbKVyZ6V/Ugc=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
 golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
+golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
diff --git a/handlers/signup.go b/handlers/signup.go
new file mode 100644
index 0000000..a0aa4f1
--- /dev/null
+++ b/handlers/signup.go
@@ -0,0 +1,74 @@
+package handlers
+
+import (
+	"github.com/gofiber/fiber/v2"
+	"github.com/golang-jwt/jwt/v5"
+	"golang.org/x/crypto/bcrypt"
+	"log"
+	"os"
+	"relay-server/database"
+	"relay-server/helpers"
+	"relay-server/models"
+	"time"
+)
+
+func Signup(c *fiber.Ctx) error {
+	db, _ := database.InitDatabase()
+	u := new(models.SignupStruct)
+	if err := c.BodyParser(u); err != nil {
+		return err
+	}
+	// Checks if username or passwords are empty
+	if u.Username == "" {
+		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "username is empty"})
+	} else if u.Password == "" {
+		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "password is empty"})
+	}
+
+	// Checks if passwords have valid length and characters
+	if !helpers.IsValidPassword(u.Password) {
+		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "invalid password"})
+	}
+	// Checks if username have valid length and characters
+	if !helpers.IsValidUsername(u.Username) {
+		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "invalid username"})
+	}
+
+	// Checks if username already exist in database
+	exist, _ := database.CheckUserExists(db, u.Username)
+	if exist {
+		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "user already exists"})
+	}
+
+	// Create password hash
+	passwordHash, err := bcrypt.GenerateFromPassword([]byte(u.Password), bcrypt.DefaultCost)
+	if err != nil {
+		log.Printf("error hashing password: %v", err)
+		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": "internal server error"})
+	}
+
+	// Insert username and password hash to database
+	userId, err := database.InsertUser(db, u.Username, string(passwordHash))
+	if err != nil {
+		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": "Internal server error"})
+	}
+
+	// Generate token with user id and username
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
+		"user_id":  userId,
+		"username": u.Username,
+	})
+	// Sign token
+	signedToken, err := token.SignedString([]byte(os.Getenv("JWT_SECRET")))
+
+	// Set token to cookies
+	cookie := new(fiber.Cookie)
+	cookie.Name = "token"
+	cookie.Value = signedToken
+	cookie.Expires = time.Now().Add(30 * 24 * time.Hour)
+	cookie.HTTPOnly = true
+
+	// If everything went well sent username and user_id assigned by database
+	return c.Status(fiber.StatusOK).JSON(fiber.Map{"message": "Successfully signed up", "username": u.Username, "user_id": userId})
+
+}
diff --git a/helpers/filter.go b/helpers/filter.go
new file mode 100644
index 0000000..f1cab62
--- /dev/null
+++ b/helpers/filter.go
@@ -0,0 +1,61 @@
+package helpers
+
+import (
+	"regexp"
+)
+
+const MIN_USERNAME_LENGTH = 4
+
+const MAX_USERNAME_LENGTH = 20
+
+const MIN_PASSWORD_LENGTH = 8
+
+const MAX_PASSWORD_LENGTH = 128
+
+const PASSWORD_REGEX = `^[A-Za-z0-9!@#$%^&*(),.?":{}|<>]+$`
+
+const USERNAME_REGEX = `^[a-zA-Z0-9_]+$`
+
+func IsValidUsername(username interface{}) bool {
+	// Checks if username is type of string
+	strUsername, ok := username.(string)
+	if !ok {
+		return false
+	}
+
+	match, _ := regexp.MatchString(USERNAME_REGEX, strUsername)
+	if !match {
+		return false
+	}
+	// Checks if username length is valid
+	if len(strUsername) < MIN_USERNAME_LENGTH {
+		return false
+	}
+	if len(strUsername) > MAX_USERNAME_LENGTH {
+		return false
+	}
+
+	return true
+}
+
+func IsValidPassword(password interface{}) bool {
+	strPassword, ok := password.(string)
+	if !ok {
+		return false
+	}
+
+	if len(strPassword) < MIN_PASSWORD_LENGTH {
+		return false
+	}
+
+	if len(strPassword) > MAX_PASSWORD_LENGTH {
+		return false
+	}
+
+	match, _ := regexp.MatchString(PASSWORD_REGEX, strPassword)
+	if !match {
+		return false
+	}
+
+	return true
+}
diff --git a/main.go b/main.go
index ba43b79..dbe8272 100644
--- a/main.go
+++ b/main.go
@@ -5,6 +5,7 @@ import (
 	"github.com/gofiber/fiber/v2"
 	"log"
 	"relay-server/database"
+	"relay-server/handlers"
 )
 
 func main() {
@@ -19,11 +20,19 @@ func main() {
 			log.Fatal(err)
 		}
 	}(db)
+	app.Get("/", func(c *fiber.Ctx) error {
+		return c.SendString("Hello, World!")
+	})
 
 	app.Get("/users", func(c *fiber.Ctx) error {
 		users, _ := database.GetUsers(db)
 		return c.JSON(fiber.Map{"users": users})
 	})
 
-	app.Listen(":3000")
+	app.Post("/api/auth/signup", handlers.Signup)
+
+	err = app.Listen(":3000")
+	if err != nil {
+		return
+	}
 }
diff --git a/models/signup.go b/models/signup.go
new file mode 100644
index 0000000..6b864dc
--- /dev/null
+++ b/models/signup.go
@@ -0,0 +1,6 @@
+package models
+
+type SignupStruct struct {
+	Username string `json:"username" xml:"username" form:"username"`
+	Password string `json:"password" xml:"password" form:"password"`
+}