diff --git a/components/InputSelect/TagSelection.tsx b/components/InputSelect/TagSelection.tsx
index 08460ea..cf03e6f 100644
--- a/components/InputSelect/TagSelection.tsx
+++ b/components/InputSelect/TagSelection.tsx
@@ -7,7 +7,7 @@ import { useTags } from "@/hooks/store/tags";
 type Props = {
   onChange: any;
   defaultValue?: {
-    value: number;
+    value?: number;
     label: string;
   }[];
   autoFocus?: boolean;
diff --git a/components/ModalContent/NewLinkModal.tsx b/components/ModalContent/NewLinkModal.tsx
index f0030e4..e5394c9 100644
--- a/components/ModalContent/NewLinkModal.tsx
+++ b/components/ModalContent/NewLinkModal.tsx
@@ -3,14 +3,13 @@ import CollectionSelection from "@/components/InputSelect/CollectionSelection";
 import TagSelection from "@/components/InputSelect/TagSelection";
 import TextInput from "@/components/TextInput";
 import unescapeString from "@/lib/client/unescapeString";
-import { LinkIncludingShortenedCollectionAndTags } from "@/types/global";
-import { useSession } from "next-auth/react";
 import { useRouter } from "next/router";
 import Modal from "../Modal";
 import { useTranslation } from "next-i18next";
 import { useCollections } from "@/hooks/store/collections";
 import { useAddLink } from "@/hooks/store/links";
 import toast from "react-hot-toast";
+import { PostLinkSchemaType } from "@/lib/shared/schemaValidation";
 
 type Props = {
   onClose: Function;
@@ -18,30 +17,19 @@ type Props = {
 
 export default function NewLinkModal({ onClose }: Props) {
   const { t } = useTranslation();
-  const { data } = useSession();
   const initial = {
     name: "",
     url: "",
     description: "",
     type: "url",
     tags: [],
-    preview: "",
-    image: "",
-    pdf: "",
-    readable: "",
-    monolith: "",
-    textContent: "",
-    icon: "",
-    iconWeight: "",
-    color: "",
     collection: {
+      id: undefined,
       name: "",
-      ownerId: data?.user.id as number,
     },
-  } as LinkIncludingShortenedCollectionAndTags;
+  } as PostLinkSchemaType;
 
-  const [link, setLink] =
-    useState<LinkIncludingShortenedCollectionAndTags>(initial);
+  const [link, setLink] = useState<PostLinkSchemaType>(initial);
 
   const addLink = useAddLink();
 
@@ -51,10 +39,10 @@ export default function NewLinkModal({ onClose }: Props) {
   const { data: collections = [] } = useCollections();
 
   const setCollection = (e: any) => {
-    if (e?.__isNew__) e.value = null;
+    if (e?.__isNew__) e.value = undefined;
     setLink({
       ...link,
-      collection: { id: e?.value, name: e?.label, ownerId: e?.ownerId },
+      collection: { id: e?.value, name: e?.label },
     });
   };
 
@@ -68,23 +56,19 @@ export default function NewLinkModal({ onClose }: Props) {
       const currentCollection = collections.find(
         (e) => e.id == Number(router.query.id)
       );
-      if (
-        currentCollection &&
-        currentCollection.ownerId &&
-        router.asPath.startsWith("/collections/")
-      )
+
+      if (currentCollection && currentCollection.ownerId)
         setLink({
           ...initial,
           collection: {
             id: currentCollection.id,
             name: currentCollection.name,
-            ownerId: currentCollection.ownerId,
           },
         });
     } else
       setLink({
         ...initial,
-        collection: { name: "Unorganized", ownerId: data?.user.id as number },
+        collection: { name: "Unorganized" },
       });
   }, []);
 
@@ -99,7 +83,7 @@ export default function NewLinkModal({ onClose }: Props) {
           toast.dismiss(load);
 
           if (error) {
-            toast.error(error.message);
+            toast.error(t(error.message));
           } else {
             onClose();
             toast.success(t("link_created"));
@@ -127,12 +111,12 @@ export default function NewLinkModal({ onClose }: Props) {
         </div>
         <div className="sm:col-span-2 col-span-5">
           <p className="mb-2">{t("collection")}</p>
-          {link.collection.name && (
+          {link.collection?.name && (
             <CollectionSelection
               onChange={setCollection}
               defaultValue={{
-                label: link.collection.name,
-                value: link.collection.id,
+                value: link.collection?.id,
+                label: link.collection?.name || "Unorganized",
               }}
             />
           )}
@@ -155,7 +139,7 @@ export default function NewLinkModal({ onClose }: Props) {
                 <p className="mb-2">{t("tags")}</p>
                 <TagSelection
                   onChange={setTags}
-                  defaultValue={link.tags.map((e) => ({
+                  defaultValue={link.tags?.map((e) => ({
                     label: e.name,
                     value: e.id,
                   }))}
@@ -164,7 +148,7 @@ export default function NewLinkModal({ onClose }: Props) {
               <div className="sm:col-span-2">
                 <p className="mb-2">{t("description")}</p>
                 <textarea
-                  value={unescapeString(link.description) as string}
+                  value={unescapeString(link.description || "") || ""}
                   onChange={(e) =>
                     setLink({ ...link, description: e.target.value })
                   }
diff --git a/components/ModalContent/UploadFileModal.tsx b/components/ModalContent/UploadFileModal.tsx
index ca78a30..219dabe 100644
--- a/components/ModalContent/UploadFileModal.tsx
+++ b/components/ModalContent/UploadFileModal.tsx
@@ -14,6 +14,7 @@ import Modal from "../Modal";
 import { useTranslation } from "next-i18next";
 import { useCollections } from "@/hooks/store/collections";
 import { useUploadFile } from "@/hooks/store/links";
+import { PostLinkSchemaType } from "@/lib/shared/schemaValidation";
 
 type Props = {
   onClose: Function;
@@ -25,27 +26,16 @@ export default function UploadFileModal({ onClose }: Props) {
 
   const initial = {
     name: "",
-    url: "",
     description: "",
     type: "url",
     tags: [],
-    preview: "",
-    image: "",
-    pdf: "",
-    readable: "",
-    monolith: "",
-    textContent: "",
-    icon: "",
-    iconWeight: "",
-    color: "",
     collection: {
+      id: undefined,
       name: "",
-      ownerId: data?.user.id as number,
     },
-  } as LinkIncludingShortenedCollectionAndTags;
+  } as PostLinkSchemaType;
 
-  const [link, setLink] =
-    useState<LinkIncludingShortenedCollectionAndTags>(initial);
+  const [link, setLink] = useState<PostLinkSchemaType>(initial);
   const [file, setFile] = useState<File>();
 
   const uploadFile = useUploadFile();
@@ -55,11 +45,11 @@ export default function UploadFileModal({ onClose }: Props) {
   const { data: collections = [] } = useCollections();
 
   const setCollection = (e: any) => {
-    if (e?.__isNew__) e.value = null;
+    if (e?.__isNew__) e.value = undefined;
 
     setLink({
       ...link,
-      collection: { id: e?.value, name: e?.label, ownerId: e?.ownerId },
+      collection: { id: e?.value, name: e?.label },
     });
   };
 
@@ -77,6 +67,7 @@ export default function UploadFileModal({ onClose }: Props) {
       const currentCollection = collections.find(
         (e) => e.id == Number(router.query.id)
       );
+
       if (
         currentCollection &&
         currentCollection.ownerId &&
@@ -87,13 +78,12 @@ export default function UploadFileModal({ onClose }: Props) {
           collection: {
             id: currentCollection.id,
             name: currentCollection.name,
-            ownerId: currentCollection.ownerId,
           },
         });
     } else
       setLink({
         ...initial,
-        collection: { name: "Unorganized", ownerId: data?.user.id as number },
+        collection: { name: "Unorganized" },
       });
   }, [router, collections]);
 
@@ -166,12 +156,12 @@ export default function UploadFileModal({ onClose }: Props) {
         </div>
         <div className="sm:col-span-2 col-span-5">
           <p className="mb-2">{t("collection")}</p>
-          {link.collection.name && (
+          {link.collection?.name && (
             <CollectionSelection
               onChange={setCollection}
               defaultValue={{
-                label: link.collection.name,
-                value: link.collection.id,
+                value: link.collection?.id,
+                label: link.collection?.name || "Unorganized",
               }}
             />
           )}
@@ -193,16 +183,16 @@ export default function UploadFileModal({ onClose }: Props) {
               <p className="mb-2">{t("tags")}</p>
               <TagSelection
                 onChange={setTags}
-                defaultValue={link.tags.map((e) => ({
-                  label: e.name,
+                defaultValue={link.tags?.map((e) => ({
                   value: e.id,
+                  label: e.name,
                 }))}
               />
             </div>
             <div className="sm:col-span-2">
               <p className="mb-2">{t("description")}</p>
               <textarea
-                value={unescapeString(link.description) as string}
+                value={unescapeString(link.description || "") || ""}
                 onChange={(e) =>
                   setLink({ ...link, description: e.target.value })
                 }
diff --git a/hooks/store/links.tsx b/hooks/store/links.tsx
index e410de9..a7f115a 100644
--- a/hooks/store/links.tsx
+++ b/hooks/store/links.tsx
@@ -13,7 +13,7 @@ import {
 } from "@/types/global";
 import { useRouter } from "next/router";
 import { useSession } from "next-auth/react";
-import Jimp from "jimp";
+import { PostLinkSchemaType } from "@/lib/shared/schemaValidation";
 
 const useLinks = (params: LinkRequestQuery = {}) => {
   const router = useRouter();
@@ -104,7 +104,15 @@ const useAddLink = () => {
   const queryClient = useQueryClient();
 
   return useMutation({
-    mutationFn: async (link: LinkIncludingShortenedCollectionAndTags) => {
+    mutationFn: async (link: PostLinkSchemaType) => {
+      if (link.url || link.type === "url") {
+        try {
+          new URL(link.url || "");
+        } catch (error) {
+          throw new Error("invalid_url_guide");
+        }
+      }
+
       const response = await fetch("/api/v1/links", {
         method: "POST",
         headers: {
@@ -124,7 +132,7 @@ const useAddLink = () => {
         if (!oldData?.links) return undefined;
         return {
           ...oldData,
-          links: [data, ...oldData.links],
+          links: [data, ...oldData?.links],
         };
       });
 
@@ -311,7 +319,7 @@ const useBulkDeleteLinks = () => {
     },
     onSuccess: (data) => {
       queryClient.setQueryData(["dashboardData"], (oldData: any) => {
-        if (!oldData.links) return undefined;
+        if (!oldData?.links) return undefined;
         return oldData.links.filter((e: any) => !data.includes(e.id));
       });
 
@@ -389,7 +397,7 @@ const useUploadFile = () => {
         if (!oldData?.links) return undefined;
         return {
           ...oldData,
-          links: [data, ...oldData.links],
+          links: [data, ...oldData?.links],
         };
       });
 
diff --git a/hooks/store/tokens.tsx b/hooks/store/tokens.tsx
index 35ac345..575befb 100644
--- a/hooks/store/tokens.tsx
+++ b/hooks/store/tokens.tsx
@@ -27,6 +27,9 @@ const useAddToken = () => {
       const response = await fetch("/api/v1/tokens", {
         body: JSON.stringify(body),
         method: "POST",
+        headers: {
+          "Content-Type": "application/json",
+        },
       });
 
       const data = await response.json();
diff --git a/lib/api/controllers/collections/postCollection.ts b/lib/api/controllers/collections/postCollection.ts
index e686a85..c09291f 100644
--- a/lib/api/controllers/collections/postCollection.ts
+++ b/lib/api/controllers/collections/postCollection.ts
@@ -1,16 +1,26 @@
 import { prisma } from "@/lib/api/db";
-import { CollectionIncludingMembersAndLinkCount } from "@/types/global";
 import createFolder from "@/lib/api/storage/createFolder";
+import {
+  PostCollectionSchema,
+  PostCollectionSchemaType,
+} from "@/lib/shared/schemaValidation";
 
 export default async function postCollection(
-  collection: CollectionIncludingMembersAndLinkCount,
+  body: PostCollectionSchemaType,
   userId: number
 ) {
-  if (!collection || collection.name.trim() === "")
+  const dataValidation = PostCollectionSchema.safeParse(body);
+
+  if (!dataValidation.success) {
     return {
-      response: "Please enter a valid collection.",
+      response: `Error: ${
+        dataValidation.error.issues[0].message
+      } [${dataValidation.error.issues[0].path.join(", ")}]`,
       status: 400,
     };
+  }
+
+  const collection = dataValidation.data;
 
   if (collection.parentId) {
     const findParentCollection = await prisma.collection.findUnique({
diff --git a/lib/api/controllers/links/postLink.ts b/lib/api/controllers/links/postLink.ts
index 852cdea..b620ee1 100644
--- a/lib/api/controllers/links/postLink.ts
+++ b/lib/api/controllers/links/postLink.ts
@@ -1,27 +1,31 @@
 import { prisma } from "@/lib/api/db";
-import { LinkIncludingShortenedCollectionAndTags } from "@/types/global";
 import fetchTitleAndHeaders from "@/lib/shared/fetchTitleAndHeaders";
 import createFolder from "@/lib/api/storage/createFolder";
 import setLinkCollection from "../../setLinkCollection";
+import {
+  PostLinkSchema,
+  PostLinkSchemaType,
+} from "@/lib/shared/schemaValidation";
 
 const MAX_LINKS_PER_USER = Number(process.env.MAX_LINKS_PER_USER) || 30000;
 
 export default async function postLink(
-  link: LinkIncludingShortenedCollectionAndTags,
+  body: PostLinkSchemaType,
   userId: number
 ) {
-  if (link.url || link.type === "url") {
-    try {
-      new URL(link.url || "");
-    } catch (error) {
-      return {
-        response:
-          "Please enter a valid Address for the Link. (It should start with http/https)",
-        status: 400,
-      };
-    }
+  const dataValidation = PostLinkSchema.safeParse(body);
+
+  if (!dataValidation.success) {
+    return {
+      response: `Error: ${
+        dataValidation.error.issues[0].message
+      } [${dataValidation.error.issues[0].path.join(", ")}]`,
+      status: 400,
+    };
   }
 
+  const link = dataValidation.data;
+
   const linkCollection = await setLinkCollection(link, userId);
 
   if (!linkCollection)
diff --git a/lib/api/controllers/migration/importFromHTMLFile.ts b/lib/api/controllers/migration/importFromHTMLFile.ts
index 59a2787..2103806 100644
--- a/lib/api/controllers/migration/importFromHTMLFile.ts
+++ b/lib/api/controllers/migration/importFromHTMLFile.ts
@@ -2,7 +2,6 @@ import { prisma } from "@/lib/api/db";
 import createFolder from "@/lib/api/storage/createFolder";
 import { JSDOM } from "jsdom";
 import { parse, Node, Element, TextNode } from "himalaya";
-import { writeFileSync } from "fs";
 
 const MAX_LINKS_PER_USER = Number(process.env.MAX_LINKS_PER_USER) || 30000;
 
@@ -155,6 +154,8 @@ const createCollection = async (
   collectionName: string,
   parentId?: number
 ) => {
+  collectionName = collectionName.trim().slice(0, 254);
+
   const findCollection = await prisma.collection.findFirst({
     where: {
       parentId,
@@ -199,6 +200,22 @@ const createLink = async (
   tags?: string[],
   importDate?: Date
 ) => {
+  url = url.trim().slice(0, 254);
+  try {
+    new URL(url);
+  } catch (e) {
+    return;
+  }
+  tags = tags?.map((tag) => tag.trim().slice(0, 49));
+  name = name?.trim().slice(0, 254);
+  description = description?.trim().slice(0, 254);
+  if (importDate) {
+    const dateString = importDate.toISOString();
+    if (dateString.length > 50) {
+      importDate = undefined;
+    }
+  }
+
   await prisma.link.create({
     data: {
       name: name || "",
diff --git a/lib/api/controllers/migration/importFromLinkwarden.ts b/lib/api/controllers/migration/importFromLinkwarden.ts
index 5e872e8..ed948d3 100644
--- a/lib/api/controllers/migration/importFromLinkwarden.ts
+++ b/lib/api/controllers/migration/importFromLinkwarden.ts
@@ -44,9 +44,9 @@ export default async function importFromLinkwarden(
                   id: userId,
                 },
               },
-              name: e.name,
-              description: e.description,
-              color: e.color,
+              name: e.name?.trim().slice(0, 254),
+              description: e.description?.trim().slice(0, 254),
+              color: e.color?.trim().slice(0, 50),
             },
           });
 
@@ -54,11 +54,19 @@ export default async function importFromLinkwarden(
 
           // Import Links
           for (const link of e.links) {
+            if (link.url) {
+              try {
+                new URL(link.url.trim());
+              } catch (err) {
+                continue;
+              }
+            }
+
             await prisma.link.create({
               data: {
-                url: link.url,
-                name: link.name,
-                description: link.description,
+                url: link.url?.trim().slice(0, 254),
+                name: link.name?.trim().slice(0, 254),
+                description: link.description?.trim().slice(0, 254),
                 collection: {
                   connect: {
                     id: newCollection.id,
@@ -69,12 +77,12 @@ export default async function importFromLinkwarden(
                   connectOrCreate: link.tags.map((tag) => ({
                     where: {
                       name_ownerId: {
-                        name: tag.name.trim(),
+                        name: tag.name?.slice(0, 49),
                         ownerId: userId,
                       },
                     },
                     create: {
-                      name: tag.name.trim(),
+                      name: tag.name?.trim().slice(0, 49),
                       owner: {
                         connect: {
                           id: userId,
diff --git a/lib/api/controllers/migration/importFromWallabag.ts b/lib/api/controllers/migration/importFromWallabag.ts
index b723d3f..a1f6a0b 100644
--- a/lib/api/controllers/migration/importFromWallabag.ts
+++ b/lib/api/controllers/migration/importFromWallabag.ts
@@ -67,14 +67,22 @@ export default async function importFromWallabag(
         createFolder({ filePath: `archives/${newCollection.id}` });
 
         for (const link of backup) {
+          if (link.url) {
+            try {
+              new URL(link.url.trim());
+            } catch (err) {
+              continue;
+            }
+          }
+
           await prisma.link.create({
             data: {
               pinnedBy: link.is_starred
                 ? { connect: { id: userId } }
                 : undefined,
-              url: link.url,
-              name: link.title || "",
-              textContent: link.content || "",
+              url: link.url?.trim().slice(0, 254),
+              name: link.title?.trim().slice(0, 254) || "",
+              textContent: link.content?.trim() || "",
               importDate: link.created_at || null,
               collection: {
                 connect: {
@@ -87,12 +95,12 @@ export default async function importFromWallabag(
                       connectOrCreate: link.tags.map((tag) => ({
                         where: {
                           name_ownerId: {
-                            name: tag.trim(),
+                            name: tag?.trim().slice(0, 49),
                             ownerId: userId,
                           },
                         },
                         create: {
-                          name: tag.trim(),
+                          name: tag?.trim().slice(0, 49),
                           owner: {
                             connect: {
                               id: userId,
diff --git a/lib/api/controllers/tokens/postToken.ts b/lib/api/controllers/tokens/postToken.ts
index faedd8a..f9b12f6 100644
--- a/lib/api/controllers/tokens/postToken.ts
+++ b/lib/api/controllers/tokens/postToken.ts
@@ -1,28 +1,32 @@
 import { prisma } from "@/lib/api/db";
+import {
+  PostTokenSchemaType,
+  PostTokenSchema,
+} from "@/lib/shared/schemaValidation";
 import { TokenExpiry } from "@/types/global";
 import crypto from "crypto";
 import { decode, encode } from "next-auth/jwt";
 
 export default async function postToken(
-  body: {
-    name: string;
-    expires: TokenExpiry;
-  },
+  body: PostTokenSchemaType,
   userId: number
 ) {
-  console.log(body);
+  const dataValidation = PostTokenSchema.safeParse(body);
 
-  const checkHasEmptyFields = !body.name || body.expires === undefined;
-
-  if (checkHasEmptyFields)
+  if (!dataValidation.success) {
     return {
-      response: "Please fill out all the fields.",
+      response: `Error: ${
+        dataValidation.error.issues[0].message
+      } [${dataValidation.error.issues[0].path.join(", ")}]`,
       status: 400,
     };
+  }
+
+  const { name, expires } = dataValidation.data;
 
   const checkIfTokenExists = await prisma.accessToken.findFirst({
     where: {
-      name: body.name,
+      name: name,
       revoked: false,
       userId,
     },
@@ -40,16 +44,16 @@ export default async function postToken(
   const oneDayInSeconds = 86400;
   let expiryDateSecond = 7 * oneDayInSeconds;
 
-  if (body.expires === TokenExpiry.oneMonth) {
+  if (expires === TokenExpiry.oneMonth) {
     expiryDate.setDate(expiryDate.getDate() + 30);
     expiryDateSecond = 30 * oneDayInSeconds;
-  } else if (body.expires === TokenExpiry.twoMonths) {
+  } else if (expires === TokenExpiry.twoMonths) {
     expiryDate.setDate(expiryDate.getDate() + 60);
     expiryDateSecond = 60 * oneDayInSeconds;
-  } else if (body.expires === TokenExpiry.threeMonths) {
+  } else if (expires === TokenExpiry.threeMonths) {
     expiryDate.setDate(expiryDate.getDate() + 90);
     expiryDateSecond = 90 * oneDayInSeconds;
-  } else if (body.expires === TokenExpiry.never) {
+  } else if (expires === TokenExpiry.never) {
     expiryDate.setDate(expiryDate.getDate() + 73000); // 200 years (not really never)
     expiryDateSecond = 73050 * oneDayInSeconds;
   } else {
@@ -75,7 +79,7 @@ export default async function postToken(
 
   const createToken = await prisma.accessToken.create({
     data: {
-      name: body.name,
+      name: name,
       userId,
       token: tokenBody?.jti as string,
       expires: expiryDate,
diff --git a/lib/api/controllers/users/postUser.ts b/lib/api/controllers/users/postUser.ts
index e987475..0f82495 100644
--- a/lib/api/controllers/users/postUser.ts
+++ b/lib/api/controllers/users/postUser.ts
@@ -2,6 +2,7 @@ import { prisma } from "@/lib/api/db";
 import type { NextApiRequest, NextApiResponse } from "next";
 import bcrypt from "bcrypt";
 import isServerAdmin from "../../isServerAdmin";
+import { PostUserSchema } from "@/lib/shared/schemaValidation";
 
 const emailEnabled =
   process.env.EMAIL_FROM && process.env.EMAIL_SERVER ? true : false;
@@ -12,13 +13,6 @@ interface Data {
   status: number;
 }
 
-interface User {
-  name: string;
-  username?: string;
-  email?: string;
-  password: string;
-}
-
 export default async function postUser(
   req: NextApiRequest,
   res: NextApiResponse
@@ -29,49 +23,34 @@ export default async function postUser(
     return { response: "Registration is disabled.", status: 400 };
   }
 
-  const body: User = req.body;
+  const dataValidation = PostUserSchema().safeParse(req.body);
 
-  const checkHasEmptyFields = emailEnabled
-    ? !body.password || !body.name || !body.email
-    : !body.username || !body.password || !body.name;
+  if (!dataValidation.success) {
+    return {
+      response: `Error: ${
+        dataValidation.error.issues[0].message
+      } [${dataValidation.error.issues[0].path.join(", ")}]`,
+      status: 400,
+    };
+  }
 
-  if (!body.password || body.password.length < 8)
-    return { response: "Password must be at least 8 characters.", status: 400 };
-
-  if (checkHasEmptyFields)
-    return { response: "Please fill out all the fields.", status: 400 };
-
-  // Check email (if enabled)
-  const checkEmail =
-    /^(([^<>()[\]\.,;:\s@\"]+(\.[^<>()[\]\.,;:\s@\"]+)*)|(\".+\"))@(([^<>()[\]\.,;:\s@\"]+\.)+[^<>()[\]\.,;:\s@\"]{2,})$/i;
-  if (emailEnabled && !checkEmail.test(body.email?.toLowerCase() || ""))
-    return { response: "Please enter a valid email.", status: 400 };
-
-  // Check username (if email was disabled)
-  const checkUsername = RegExp("^[a-z0-9_-]{3,31}$");
+  const { name, email, password } = dataValidation.data;
+  let { username } = dataValidation.data;
 
   const autoGeneratedUsername = "user" + Math.round(Math.random() * 1000000000);
 
-  if (body.username && !checkUsername.test(body.username?.toLowerCase()))
-    return {
-      response:
-        "Username has to be between 3-30 characters, no spaces and special characters are allowed.",
-      status: 400,
-    };
-  else if (!body.username) {
-    body.username = autoGeneratedUsername;
+  if (!username) {
+    username = autoGeneratedUsername;
   }
 
   const checkIfUserExists = await prisma.user.findFirst({
     where: {
       OR: [
         {
-          email: body.email ? body.email.toLowerCase().trim() : undefined,
+          email: email ? email.toLowerCase().trim() : undefined,
         },
         {
-          username: body.username
-            ? body.username.toLowerCase().trim()
-            : undefined,
+          username: username ? username.toLowerCase().trim() : undefined,
         },
       ],
     },
@@ -83,7 +62,7 @@ export default async function postUser(
 
     const saltRounds = 10;
 
-    const hashedPassword = bcrypt.hashSync(body.password, saltRounds);
+    const hashedPassword = bcrypt.hashSync(password, saltRounds);
 
     // Subscription dates
     const currentPeriodStart = new Date();
@@ -93,12 +72,11 @@ export default async function postUser(
     if (isAdmin) {
       const user = await prisma.user.create({
         data: {
-          name: body.name,
+          name: name,
           username: emailEnabled
-            ? (body.username as string).toLowerCase().trim() ||
-              autoGeneratedUsername
-            : (body.username as string).toLowerCase().trim(),
-          email: emailEnabled ? body.email?.toLowerCase().trim() : undefined,
+            ? (username as string) || autoGeneratedUsername
+            : (username as string),
+          email: emailEnabled ? email : undefined,
           password: hashedPassword,
           emailVerified: new Date(),
           subscriptions: stripeEnabled
@@ -131,11 +109,9 @@ export default async function postUser(
     } else {
       await prisma.user.create({
         data: {
-          name: body.name,
-          username: emailEnabled
-            ? autoGeneratedUsername
-            : (body.username as string).toLowerCase().trim(),
-          email: emailEnabled ? body.email?.toLowerCase().trim() : undefined,
+          name: name,
+          username: emailEnabled ? autoGeneratedUsername : (username as string),
+          email: emailEnabled ? email : undefined,
           password: hashedPassword,
         },
       });
diff --git a/lib/api/setLinkCollection.ts b/lib/api/setLinkCollection.ts
index 901e585..c26de99 100644
--- a/lib/api/setLinkCollection.ts
+++ b/lib/api/setLinkCollection.ts
@@ -1,13 +1,10 @@
-import { LinkIncludingShortenedCollectionAndTags } from "@/types/global";
 import { prisma } from "./db";
 import getPermission from "./getPermission";
 import { UsersAndCollections } from "@prisma/client";
+import { PostLinkSchemaType } from "../shared/schemaValidation";
 
-const setLinkCollection = async (
-  link: LinkIncludingShortenedCollectionAndTags,
-  userId: number
-) => {
-  if (link?.collection?.id && typeof link?.collection?.id === "number") {
+const setLinkCollection = async (link: PostLinkSchemaType, userId: number) => {
+  if (link.collection?.id && typeof link.collection?.id === "number") {
     const existingCollection = await prisma.collection.findUnique({
       where: {
         id: link.collection.id,
@@ -29,7 +26,7 @@ const setLinkCollection = async (
       return null;
 
     return existingCollection;
-  } else if (link?.collection?.name) {
+  } else if (link.collection?.name) {
     if (link.collection.name === "Unorganized") {
       const firstTopLevelUnorganizedCollection =
         await prisma.collection.findFirst({
diff --git a/lib/shared/schemaValidation.ts b/lib/shared/schemaValidation.ts
new file mode 100644
index 0000000..014eee3
--- /dev/null
+++ b/lib/shared/schemaValidation.ts
@@ -0,0 +1,114 @@
+import { ArchivedFormat, TokenExpiry } from "@/types/global";
+import { z } from "zod";
+
+// const stringField = z.string({
+//   errorMap: (e) => ({
+//     message: `Invalid ${e.path}.`,
+//   }),
+// });
+
+export const ForgotPasswordSchema = z.object({
+  email: z.string().email(),
+});
+
+export const ResetPasswordSchema = z.object({
+  token: z.string(),
+  password: z.string().min(8),
+});
+
+export const VerifyEmailSchema = z.object({
+  token: z.string(),
+});
+
+export const PostTokenSchema = z.object({
+  name: z.string().max(50),
+  expires: z.nativeEnum(TokenExpiry),
+});
+
+export type PostTokenSchemaType = z.infer<typeof PostTokenSchema>;
+
+export const PostUserSchema = () => {
+  const emailEnabled =
+    process.env.EMAIL_FROM && process.env.EMAIL_SERVER ? true : false;
+
+  return z.object({
+    name: z.string().trim().min(1).max(50),
+    password: z.string().min(8),
+    email: emailEnabled
+      ? z.string().trim().email().toLowerCase()
+      : z.string().optional(),
+    username: z
+      .string()
+      .trim()
+      .min(3)
+      .max(50)
+      .regex(/^[a-z0-9_-]{3,50}$/),
+  });
+};
+
+export const PostSessionSchema = z.object({
+  username: z.string().min(3).max(50),
+  password: z.string().min(8),
+  sessionName: z.string().trim().max(50).optional(),
+});
+
+export const PostLinkSchema = z.object({
+  type: z.enum(["url", "pdf", "image"]),
+  url: z.string().trim().max(255).url().optional(),
+  name: z.string().trim().max(255).optional(),
+  description: z.string().trim().max(255).optional(),
+  collection: z
+    .object({
+      id: z.number().optional(),
+      name: z.string().trim().max(255).optional(),
+    })
+    .optional(),
+  tags:
+    z
+      .array(
+        z.object({
+          id: z.number().optional(),
+          name: z.string().trim().max(50),
+        })
+      )
+      .optional() || [],
+});
+
+export type PostLinkSchemaType = z.infer<typeof PostLinkSchema>;
+
+const ACCEPTED_TYPES = [
+  "image/jpeg",
+  "image/jpg",
+  "image/png",
+  "application/pdf",
+];
+const NEXT_PUBLIC_MAX_FILE_BUFFER = Number(
+  process.env.NEXT_PUBLIC_MAX_FILE_BUFFER || 10
+);
+const MAX_FILE_SIZE = NEXT_PUBLIC_MAX_FILE_BUFFER * 1024 * 1024;
+export const UploadFileSchema = z.object({
+  file: z
+    .any()
+    .refine((files) => files?.length == 1, "File is required.")
+    .refine(
+      (files) => files?.[0]?.size <= MAX_FILE_SIZE,
+      `Max file size is ${MAX_FILE_SIZE}MB.`
+    )
+    .refine(
+      (files) => ACCEPTED_TYPES.includes(files?.[0]?.mimetype),
+      `Only ${ACCEPTED_TYPES.join(", ")} files are accepted.`
+    ),
+  id: z.number(),
+  format: z.nativeEnum(ArchivedFormat),
+});
+
+export const PostCollectionSchema = z.object({
+  name: z.string().trim().max(255),
+  description: z.string().trim().max(255).optional(),
+  color: z.string().trim().max(7).optional(),
+  icon: z.string().trim().max(50).optional(),
+  iconWeight: z.string().trim().max(50).optional(),
+  parentId: z.number().optional(),
+});
+
+export type PostCollectionSchemaType = z.infer<typeof PostCollectionSchema>;
diff --git a/package.json b/package.json
index 0e72474..4c6a324 100644
--- a/package.json
+++ b/package.json
@@ -80,6 +80,7 @@
     "stripe": "^12.13.0",
     "tailwind-merge": "^2.3.0",
     "vaul": "^0.9.1",
+    "zod": "^3.23.8",
     "zustand": "^4.3.8"
   },
   "devDependencies": {
diff --git a/pages/api/v1/archives/[linkId].ts b/pages/api/v1/archives/[linkId].ts
index 2120510..91d0bb0 100644
--- a/pages/api/v1/archives/[linkId].ts
+++ b/pages/api/v1/archives/[linkId].ts
@@ -11,6 +11,7 @@ import fs from "fs";
 import verifyToken from "@/lib/api/verifyToken";
 import generatePreview from "@/lib/api/generatePreview";
 import createFolder from "@/lib/api/storage/createFolder";
+import { UploadFileSchema } from "@/lib/shared/schemaValidation";
 
 export const config = {
   api: {
@@ -138,6 +139,20 @@ export default async function Index(req: NextApiRequest, res: NextApiResponse) {
         "image/jpeg",
       ];
 
+      const dataValidation = UploadFileSchema.safeParse({
+        id: Number(req.query.linkId),
+        format: Number(req.query.format),
+        file: files.file,
+      });
+
+      if (!dataValidation.success) {
+        return res.status(400).json({
+          response: `Error: ${
+            dataValidation.error.issues[0].message
+          } [${dataValidation.error.issues[0].path.join(", ")}]`,
+        });
+      }
+
       if (
         err ||
         !files.file ||
diff --git a/pages/api/v1/auth/forgot-password.ts b/pages/api/v1/auth/forgot-password.ts
index 66fb807..9c1da76 100644
--- a/pages/api/v1/auth/forgot-password.ts
+++ b/pages/api/v1/auth/forgot-password.ts
@@ -1,5 +1,6 @@
 import { prisma } from "@/lib/api/db";
 import sendPasswordResetRequest from "@/lib/api/sendPasswordResetRequest";
+import { ForgotPasswordSchema } from "@/lib/shared/schemaValidation";
 import type { NextApiRequest, NextApiResponse } from "next";
 
 export default async function forgotPassword(
@@ -13,14 +14,18 @@ export default async function forgotPassword(
           "This action is disabled because this is a read-only demo of Linkwarden.",
       });
 
-    const email = req.body.email;
+    const dataValidation = ForgotPasswordSchema.safeParse(req.body);
 
-    if (!email) {
+    if (!dataValidation.success) {
       return res.status(400).json({
-        response: "Invalid email.",
+        response: `Error: ${
+          dataValidation.error.issues[0].message
+        } [${dataValidation.error.issues[0].path.join(", ")}]`,
       });
     }
 
+    const { email } = dataValidation.data;
+
     const recentPasswordRequestsCount = await prisma.passwordResetToken.count({
       where: {
         identifier: email,
@@ -45,7 +50,7 @@ export default async function forgotPassword(
 
     if (!user || !user.email) {
       return res.status(400).json({
-        response: "Invalid email.",
+        response: "No user found with that email.",
       });
     }
 
diff --git a/pages/api/v1/auth/reset-password.ts b/pages/api/v1/auth/reset-password.ts
index 5bbadfd..09f9e31 100644
--- a/pages/api/v1/auth/reset-password.ts
+++ b/pages/api/v1/auth/reset-password.ts
@@ -1,6 +1,7 @@
 import { prisma } from "@/lib/api/db";
 import type { NextApiRequest, NextApiResponse } from "next";
 import bcrypt from "bcrypt";
+import { ResetPasswordSchema } from "@/lib/shared/schemaValidation";
 
 export default async function resetPassword(
   req: NextApiRequest,
@@ -13,20 +14,17 @@ export default async function resetPassword(
           "This action is disabled because this is a read-only demo of Linkwarden.",
       });
 
-    const token = req.body.token;
-    const password = req.body.password;
+    const dataValidation = ResetPasswordSchema.safeParse(req.body);
 
-    if (!password || password.length < 8) {
+    if (!dataValidation.success) {
       return res.status(400).json({
-        response: "Password must be at least 8 characters.",
+        response: `Error: ${
+          dataValidation.error.issues[0].message
+        } [${dataValidation.error.issues[0].path.join(", ")}]`,
       });
     }
 
-    if (!token || typeof token !== "string") {
-      return res.status(400).json({
-        response: "Invalid token.",
-      });
-    }
+    const { token, password } = dataValidation.data;
 
     // Hashed password
     const saltRounds = 10;
diff --git a/pages/api/v1/auth/verify-email.ts b/pages/api/v1/auth/verify-email.ts
index 41a9d0c..141ae3d 100644
--- a/pages/api/v1/auth/verify-email.ts
+++ b/pages/api/v1/auth/verify-email.ts
@@ -1,5 +1,6 @@
 import { prisma } from "@/lib/api/db";
 import updateCustomerEmail from "@/lib/api/updateCustomerEmail";
+import { VerifyEmailSchema } from "@/lib/shared/schemaValidation";
 import type { NextApiRequest, NextApiResponse } from "next";
 
 export default async function verifyEmail(
@@ -13,14 +14,18 @@ export default async function verifyEmail(
           "This action is disabled because this is a read-only demo of Linkwarden.",
       });
 
-    const token = req.query.token;
+    const dataValidation = VerifyEmailSchema.safeParse(req.query);
 
-    if (!token || typeof token !== "string") {
+    if (!dataValidation.success) {
       return res.status(400).json({
-        response: "Invalid token.",
+        response: `Error: ${
+          dataValidation.error.issues[0].message
+        } [${dataValidation.error.issues[0].path.join(", ")}]`,
       });
     }
 
+    const { token } = dataValidation.data;
+
     // Check token in db
     const verifyToken = await prisma.verificationToken.findFirst({
       where: {
diff --git a/pages/api/v1/session/index.ts b/pages/api/v1/session/index.ts
index bd3e50b..294c4ac 100644
--- a/pages/api/v1/session/index.ts
+++ b/pages/api/v1/session/index.ts
@@ -1,12 +1,23 @@
 import type { NextApiRequest, NextApiResponse } from "next";
 import verifyByCredentials from "@/lib/api/verifyByCredentials";
 import createSession from "@/lib/api/controllers/session/createSession";
+import { PostSessionSchema } from "@/lib/shared/schemaValidation";
 
 export default async function session(
   req: NextApiRequest,
   res: NextApiResponse
 ) {
-  const { username, password, sessionName } = req.body;
+  const dataValidation = PostSessionSchema.safeParse(req.body);
+
+  if (!dataValidation.success) {
+    return res.status(400).json({
+      response: `Error: ${
+        dataValidation.error.issues[0].message
+      } [${dataValidation.error.issues[0].path.join(", ")}]`,
+    });
+  }
+
+  const { username, password, sessionName } = dataValidation.data;
 
   const user = await verifyByCredentials({ username, password });
 
diff --git a/pages/api/v1/tokens/index.ts b/pages/api/v1/tokens/index.ts
index bc5117e..e0f75ce 100644
--- a/pages/api/v1/tokens/index.ts
+++ b/pages/api/v1/tokens/index.ts
@@ -17,7 +17,7 @@ export default async function tokens(
           "This action is disabled because this is a read-only demo of Linkwarden.",
       });
 
-    const token = await postToken(JSON.parse(req.body), user.id);
+    const token = await postToken(req.body, user.id);
     return res.status(token.status).json({ response: token.response });
   } else if (req.method === "GET") {
     const token = await getTokens(user.id);
diff --git a/pages/settings/account.tsx b/pages/settings/account.tsx
index 70d01f2..2d92518 100644
--- a/pages/settings/account.tsx
+++ b/pages/settings/account.tsx
@@ -113,6 +113,12 @@ export default function Account() {
       }
     );
 
+    if (user.locale !== account.locale) {
+      setTimeout(() => {
+        location.reload();
+      }, 1000);
+    }
+
     setSubmitLoader(false);
   };
 
diff --git a/public/locales/en/common.json b/public/locales/en/common.json
index b6b2ef3..ac1fbd2 100644
--- a/public/locales/en/common.json
+++ b/public/locales/en/common.json
@@ -393,5 +393,6 @@
   "change_icon": "Change Icon",
   "upload_preview_image": "Upload Preview Image",
   "columns": "Columns",
-  "default": "Default"
+  "default": "Default",
+  "invalid_url_guide":"Please enter a valid Address for the Link. (It should start with http/https)"
 }
\ No newline at end of file
diff --git a/yarn.lock b/yarn.lock
index 55d157e..d3403a7 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -6511,6 +6511,11 @@ zod@3.21.4:
   resolved "https://registry.yarnpkg.com/zod/-/zod-3.21.4.tgz#10882231d992519f0a10b5dd58a38c9dabbb64db"
   integrity sha512-m46AKbrzKVzOzs/DZgVnG5H55N1sv1M8qZU3A8RIKbs3mrACDNeIOeilDymVb2HdmP8uwshOCF4uJ8uM9rCqJw==
 
+zod@^3.23.8:
+  version "3.23.8"
+  resolved "https://registry.yarnpkg.com/zod/-/zod-3.23.8.tgz#e37b957b5d52079769fb8097099b592f0ef4067d"
+  integrity sha512-XBx9AXhXktjUqnepgTiE5flcKIYWi/rme0Eaj+5Y0lftuGBq+jyRu/md4WnuxqgP1ubdpNCsYEYPxrzVHD8d6g==
+
 zustand@^4.3.8:
   version "4.3.8"
   resolved "https://registry.yarnpkg.com/zustand/-/zustand-4.3.8.tgz#37113df8e9e1421b0be1b2dca02b49b76210e7c4"