diff --git a/src/components/AuthRequired.tsx b/src/components/AuthRequired.tsx
index f757037..8da9261 100644
--- a/src/components/AuthRequired.tsx
+++ b/src/components/AuthRequired.tsx
@@ -1,13 +1,15 @@
+import PATHS from "constants/paths";
 import { useSession } from "next-auth/react";
 import { useRouter } from "next/router";
 
+// Component used to access to the session client side
 export default function Auth({ children }) {
   const router = useRouter();
   const { status } = useSession({
     required: true,
     onUnauthenticated: () =>
       router.push(
-        `/signin?info=${encodeURI(
+        `${PATHS.LOGIN}?info=${encodeURI(
           "Vous devez être connecté pour accéder à cette page"
         )}`
       ),
diff --git a/src/components/Links/LinkItem.tsx b/src/components/Links/LinkItem.tsx
index 7a50027..0132624 100644
--- a/src/components/Links/LinkItem.tsx
+++ b/src/components/Links/LinkItem.tsx
@@ -3,6 +3,7 @@ import { motion } from "framer-motion";
 import LinkTag from "next/link";
 import { AiFillStar } from "react-icons/ai";
 
+import PATHS from "constants/paths";
 import { Link } from "types";
 
 import EditItem from "components/QuickActions/EditItem";
@@ -30,7 +31,7 @@ export default function LinkItem({
       categoryId: link.category.id,
     };
     axios
-      .put(`/api/link/edit/${link.id}`, payload)
+      .put(`${PATHS.API.LINK.EDIT}/${link.id}`, payload)
       .then(() => toggleFavorite(link.id))
       .catch(console.error);
   };
diff --git a/src/components/MessageManager/MessageManager.tsx b/src/components/MessageManager/MessageManager.tsx
index 893178a..1d3de07 100644
--- a/src/components/MessageManager/MessageManager.tsx
+++ b/src/components/MessageManager/MessageManager.tsx
@@ -1,3 +1,5 @@
+import { useRouter } from "next/dist/client/router";
+
 import styles from "./message-manager.module.scss";
 
 interface MessageManagerProps {
@@ -10,11 +12,20 @@ export default function MessageManager({
   success,
   info,
 }: MessageManagerProps) {
+  const infoUrl = useRouter().query?.info as string;
+  const errorUrl = useRouter().query?.error as string;
+  const successUrl = useRouter().query?.success as string;
+
   return (
     <>
       {info && <div className={styles["info-msg"]}>{info}</div>}
+      {infoUrl && <div className={styles["info-msg"]}>{infoUrl}</div>}
+
       {error && <div className={styles["error-msg"]}>{error}</div>}
+      {errorUrl && <div className={styles["error-msg"]}>{errorUrl}</div>}
+
       {success && <div className={styles["success-msg"]}>{success}</div>}
+      {successUrl && <div className={styles["success-msg"]}>{successUrl}</div>}
     </>
   );
 }
diff --git a/src/components/SideMenu/SideMenu.tsx b/src/components/SideMenu/SideMenu.tsx
index fea87ad..68396bb 100644
--- a/src/components/SideMenu/SideMenu.tsx
+++ b/src/components/SideMenu/SideMenu.tsx
@@ -6,6 +6,7 @@ import Favorites from "./Favorites/Favorites";
 import UserCard from "./UserCard/UserCard";
 
 import { Category, Link } from "types";
+import PATHS from "constants/paths";
 
 import styles from "./sidemenu.module.scss";
 
@@ -68,11 +69,11 @@ function MenuControls({
         <kbd>S</kbd>
       </div>
       <div className={styles["action"]}>
-        <LinkTag href={"/category/create"}>Créer categorie</LinkTag>
+        <LinkTag href={PATHS.CATEGORY.CREATE}>Créer categorie</LinkTag>
         <kbd>C</kbd>
       </div>
       <div className={styles["action"]}>
-        <LinkTag href={`/link/create?categoryId=${categoryActive.id}`}>
+        <LinkTag href={`${PATHS.LINK.CREATE}?categoryId=${categoryActive.id}`}>
           Créer lien
         </LinkTag>
         <kbd>L</kbd>
diff --git a/src/components/SideMenu/UserCard/UserCard.tsx b/src/components/SideMenu/UserCard/UserCard.tsx
index 4badeb5..d3941ae 100644
--- a/src/components/SideMenu/UserCard/UserCard.tsx
+++ b/src/components/SideMenu/UserCard/UserCard.tsx
@@ -2,6 +2,7 @@ import { signOut, useSession } from "next-auth/react";
 import Image from "next/image";
 import { FiLogOut } from "react-icons/fi";
 
+import PATHS from "constants/paths";
 import styles from "./user-card.module.scss";
 
 export default function UserCard() {
@@ -18,7 +19,7 @@ export default function UserCard() {
         {data.user.name}
       </div>
       <button
-        onClick={() => signOut({ callbackUrl: "/signin" })}
+        onClick={() => signOut({ callbackUrl: PATHS.LOGIN })}
         className="reset"
       >
         <FiLogOut size={24} />
diff --git a/src/constants/paths.ts b/src/constants/paths.ts
new file mode 100644
index 0000000..133dcb7
--- /dev/null
+++ b/src/constants/paths.ts
@@ -0,0 +1,30 @@
+const PATHS = {
+  LOGIN: "/signin",
+  HOME: "/",
+  CATEGORY: {
+    CREATE: "/category/create",
+    EDIT: "/category/edit",
+    REMOVE: "/category/remove",
+  },
+  LINK: {
+    CREATE: "/link/create",
+    EDIT: "/link/edit",
+    REMOVE: "/link/remove",
+  },
+  API: {
+    CATEGORY: {
+      CREATE: "/category/create",
+      EDIT: "/category/edit",
+      REMOVE: "/category/remove",
+    },
+    LINK: {
+      CREATE: "/link/create",
+      EDIT: "/link/edit",
+      REMOVE: "/link/remove",
+    },
+  },
+  NOT_FOUND: "/404",
+  SERVER_ERROR: "/505",
+};
+
+export default PATHS;
diff --git a/src/pages/api/auth/[...nextauth].ts b/src/pages/api/auth/[...nextauth].ts
index e76194b..35e4061 100644
--- a/src/pages/api/auth/[...nextauth].ts
+++ b/src/pages/api/auth/[...nextauth].ts
@@ -1,4 +1,5 @@
 import { PrismaClient } from "@prisma/client";
+import PATHS from "constants/paths";
 import NextAuth from "next-auth";
 import GoogleProvider from "next-auth/providers/google";
 
@@ -30,13 +31,16 @@ export default NextAuth({
       );
       if (accountParam.provider !== "google") {
         return (
-          "/signin?error=" + encodeURI("Authentitifcation via Google requise")
+          PATHS.LOGIN +
+          "?error=" +
+          encodeURI("Authentitifcation via Google requise")
         );
       }
       const email = profile?.email;
       if (email === "") {
         return (
-          "/signin?error=" +
+          PATHS.LOGIN +
+          "?error=" +
           encodeURI(
             "Impossible de récupérer l'email associé à ce compte Google"
           )
@@ -45,7 +49,8 @@ export default NextAuth({
       const googleId = profile?.sub;
       if (googleId === "") {
         return (
-          "/signin?error=" +
+          PATHS.LOGIN +
+          "?error=" +
           encodeURI(
             "Impossible de récupérer l'identifiant associé à ce compte Google"
           )
@@ -70,7 +75,8 @@ export default NextAuth({
             return true;
           }
           return (
-            "/signin?error=" +
+            PATHS.LOGIN +
+            "?error=" +
             encodeURI(
               "Vous n'êtes pas autorisé à vous connecter avec ce compte Google"
             )
@@ -81,15 +87,16 @@ export default NextAuth({
       } catch (error) {
         console.error(error);
         return (
-          "/signin?error=" +
+          PATHS.LOGIN +
+          "?error=" +
           encodeURI("Une erreur est survenue lors de l'authentification")
         );
       }
     },
   },
   pages: {
-    signIn: "/signin",
-    error: "/signin",
+    signIn: PATHS.LOGIN,
+    error: PATHS.LOGIN,
   },
   session: {
     maxAge: 60 * 60 * 6, // Session de 6 heures
diff --git a/src/pages/index.tsx b/src/pages/index.tsx
index 533dca6..9742e5b 100644
--- a/src/pages/index.tsx
+++ b/src/pages/index.tsx
@@ -9,18 +9,20 @@ import SearchModal from "components/SearchModal/SearchModal";
 import SideMenu from "components/SideMenu/SideMenu";
 
 import * as Keys from "constants/keys";
+import PATHS from "constants/paths";
 import useModal from "hooks/useModal";
 import { Category, Link, SearchItem } from "types";
-import { prisma } from "utils/back";
+
 import { BuildCategory } from "utils/front";
 import { pushStateVanilla } from "utils/link";
+import prisma from "utils/prisma";
 
-interface HomeProps {
+interface HomePageProps {
   categories: Category[];
   currentCategory: Category | undefined;
 }
 
-function Home(props: HomeProps) {
+function Home(props: HomePageProps) {
   const router = useRouter();
   const modal = useModal();
 
@@ -46,7 +48,10 @@ function Home(props: HomeProps) {
   ): SearchItem => ({
     id: item.id,
     name: item.name,
-    url: type === "link" ? (item as Link).url : `/?categoryId=${item.id}`,
+    url:
+      type === "link"
+        ? (item as Link).url
+        : `${PATHS.HOME}?categoryId=${item.id}`,
     type,
     category: type === "link" ? (item as Link).category : undefined,
   });
@@ -92,7 +97,7 @@ function Home(props: HomeProps) {
 
   const handleSelectCategory = (category: Category) => {
     setCategoryActive(category);
-    pushStateVanilla(`/?categoryId=${category.id}`);
+    pushStateVanilla(`${PATHS.HOME}?categoryId=${category.id}`);
   };
 
   useHotkeys(
@@ -111,7 +116,7 @@ function Home(props: HomeProps) {
   useHotkeys(
     Keys.OPEN_CREATE_LINK_KEY,
     () => {
-      router.push(`/link/create?categoryId=${categoryActive.id}`);
+      router.push(`${PATHS.LINK.CREATE}?categoryId=${categoryActive.id}`);
     },
     {
       enabled: !modal.isShowing,
@@ -189,7 +194,7 @@ export async function getServerSideProps({ query }) {
   if (categoriesDB.length === 0) {
     return {
       redirect: {
-        destination: "/category/create",
+        destination: PATHS.CATEGORY.CREATE,
       },
     };
   }
diff --git a/src/pages/signin.tsx b/src/pages/signin.tsx
index 8635cba..332b30f 100644
--- a/src/pages/signin.tsx
+++ b/src/pages/signin.tsx
@@ -1,50 +1,35 @@
 import { Provider } from "next-auth/providers";
-import { getProviders, signIn, useSession } from "next-auth/react";
+import { getProviders, signIn } from "next-auth/react";
 import { NextSeo } from "next-seo";
 import Link from "next/link";
-import { useRouter } from "next/router";
 
 import MessageManager from "components/MessageManager/MessageManager";
+import PATHS from "constants/paths";
 
 import styles from "styles/login.module.scss";
 
-export default function SignIn({ providers }: { providers: Provider[] }) {
-  const { data: session, status } = useSession();
-  const info = useRouter().query?.info as string;
-  const error = useRouter().query?.error as string;
-
-  if (status === "loading") {
-    return (
-      <div className="App" style={{ alignItems: "center" }}>
-        <p style={{ height: "fit-content" }}>
-          Chargement de la session en cours
-        </p>
-      </div>
-    );
-  }
-
+interface SignInProps {
+  providers: Provider[];
+}
+export default function SignIn({ providers }: SignInProps) {
   return (
     <>
       <NextSeo title="Authentification" />
       <div className="App">
         <div className={styles["wrapper"]}>
           <h2>Se connecter</h2>
-          <MessageManager error={error} info={info} />
-          {session !== null && (
-            <MessageManager info="Vous êtes déjà connecté" />
-          )}
+          <MessageManager />
           <div className={styles["providers"]}>
             {Object.values(providers).map(({ name, id }) => (
               <button
+                onClick={() => signIn(id, { callbackUrl: PATHS.HOME })}
                 key={id}
-                onClick={() => signIn(id, { callbackUrl: "/" })}
-                disabled={session !== null}
               >
                 Continuer avec {name}
               </button>
             ))}
           </div>
-          <Link href="/">← Revenir à l'accueil</Link>
+          <Link href={PATHS.HOME}>← Revenir à l'accueil</Link>
         </div>
       </div>
     </>
diff --git a/src/utils/back.ts b/src/utils/back.ts
deleted file mode 100644
index 901f3a0..0000000
--- a/src/utils/back.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-import { PrismaClient } from "@prisma/client";
-
-export const prisma = new PrismaClient();
diff --git a/src/utils/prisma.ts b/src/utils/prisma.ts
new file mode 100644
index 0000000..b5bf6ce
--- /dev/null
+++ b/src/utils/prisma.ts
@@ -0,0 +1,5 @@
+import { PrismaClient } from "@prisma/client";
+
+const prisma = new PrismaClient();
+
+export default prisma;