diff --git a/README.md b/README.md
index 492c246..6b540c2 100644
--- a/README.md
+++ b/README.md
@@ -20,14 +20,15 @@ Expect frequent improvements.
 
 **Next up:**
 
+- [ ] More custom model settings
+- [ ] Regenerate & edit responses
 - [ ] Saving via data export
 - [ ] Folders
-- [ ] Custom model settings
 - [ ] Prompt templates
-- [ ] Regenerate & edit responses
 
 **Recent updates:**
 
+- [x] Custom system prompt (3/21/23)
 - [x] Error handling (3/20/23)
 - [x] GPT-4 support (access required) (3/20/23)
 - [x] Search conversations (3/19/23)
@@ -52,7 +53,7 @@ Modify the system prompt in `utils/index.ts`.
 
 Host your own live version of Chatbot UI with Vercel.
 
-[![Deploy with Vercel](https://vercel.com/button)](https://vercel.com/new/clone?repository-url=https%3A%2F%2Fgithub.com%2Fmckaywrigley%2Fchatbot-ui&envDescription=Your%20OpenAI%20API%20Key.%20Chat%20will%20not%20work%20if%20you%20don't%20provide%20it.)
+[![Deploy with Vercel](https://vercel.com/button)](https://vercel.com/new/clone?repository-url=https%3A%2F%2Fgithub.com%2Fmckaywrigley%2Fchatbot-ui)
 
 **Replit**
 
diff --git a/components/Chat/Chat.tsx b/components/Chat/Chat.tsx
index 85ddd8b..6a997b1 100644
--- a/components/Chat/Chat.tsx
+++ b/components/Chat/Chat.tsx
@@ -1,10 +1,11 @@
-import { Conversation, Message, OpenAIModel } from "@/types";
+import { Conversation, KeyValuePair, Message, OpenAIModel } from "@/types";
 import { FC, useEffect, useRef, useState } from "react";
 import { ChatInput } from "./ChatInput";
 import { ChatLoader } from "./ChatLoader";
 import { ChatMessage } from "./ChatMessage";
 import { ModelSelect } from "./ModelSelect";
 import { Regenerate } from "./Regenerate";
+import { SystemPrompt } from "./SystemPrompt";
 
 interface Props {
   conversation: Conversation;
@@ -15,20 +16,10 @@ interface Props {
   loading: boolean;
   lightMode: "light" | "dark";
   onSend: (message: Message, isResend: boolean) => void;
-  onModelChange: (conversation: Conversation, model: OpenAIModel) => void;
+  onUpdateConversation: (conversation: Conversation, data: KeyValuePair) => void;
 }
 
-export const Chat: FC<Props> = ({
-  conversation,
-  models,
-  messageIsStreaming,
-  modelError,
-  messageError,
-  loading,
-  lightMode,
-  onSend,
-  onModelChange,
-}) => {
+export const Chat: FC<Props> = ({ conversation, models, messageIsStreaming, modelError, messageError, loading, lightMode, onSend, onUpdateConversation }) => {
   const [currentMessage, setCurrentMessage] = useState<Message>();
 
   const messagesEndRef = useRef<HTMLDivElement>(null);
@@ -46,38 +37,36 @@ export const Chat: FC<Props> = ({
       {modelError ? (
         <div className="flex flex-col justify-center mx-auto h-full w-[300px] sm:w-[500px] space-y-6">
           <div className="text-center text-red-500">Error fetching models.</div>
-          <div className="text-center text-red-500">
-            Make sure your OpenAI API key is set in the bottom left of the
-            sidebar or in a .env.local file and refresh.
-          </div>
-          <div className="text-center text-red-500">
-            If you completed this step, OpenAI may be experiencing issues.
-          </div>
+          <div className="text-center text-red-500">Make sure your OpenAI API key is set in the bottom left of the sidebar or in a .env.local file and refresh.</div>
+          <div className="text-center text-red-500">If you completed this step, OpenAI may be experiencing issues.</div>
         </div>
       ) : (
         <>
           <div>
             {conversation.messages.length === 0 ? (
               <>
-                <div className="flex justify-center pt-8">
-                  <ModelSelect
-                    model={conversation.model}
-                    models={models}
-                    onModelChange={(model) =>
-                      onModelChange(conversation, model)
-                    }
-                  />
-                </div>
+                <div className="flex flex-col mx-auto pt-12 space-y-10 w-[350px] sm:w-[600px]">
+                  <div className="text-4xl text-center text-neutral-600 dark:text-neutral-200">{models.length === 0 ? "Loading..." : "Chatbot UI"}</div>
 
-                <div className="text-4xl text-center text-neutral-600 dark:text-neutral-200 pt-[160px] sm:pt-[280px]">
-                  {models.length === 0 ? "Loading..." : "Chatbot UI"}
+                  {models.length > 0 && (
+                    <div className="flex flex-col h-full space-y-4 border p-4 rounded border-neutral-500">
+                      <ModelSelect
+                        model={conversation.model}
+                        models={models}
+                        onModelChange={(model) => onUpdateConversation(conversation, { key: "model", value: model })}
+                      />
+
+                      <SystemPrompt
+                        conversation={conversation}
+                        onChangePrompt={(prompt) => onUpdateConversation(conversation, { key: "prompt", value: prompt })}
+                      />
+                    </div>
+                  )}
                 </div>
               </>
             ) : (
               <>
-                <div className="flex justify-center py-2 text-neutral-500 bg-neutral-100 dark:bg-[#444654] dark:text-neutral-200 text-sm border border-b-neutral-300 dark:border-none">
-                  Model: {conversation.model.name}
-                </div>
+                <div className="flex justify-center py-2 text-neutral-500 bg-neutral-100 dark:bg-[#444654] dark:text-neutral-200 text-sm border border-b-neutral-300 dark:border-none">Model: {conversation.model.name}</div>
 
                 {conversation.messages.map((message, index) => (
                   <ChatMessage
diff --git a/components/Chat/ChatInput.tsx b/components/Chat/ChatInput.tsx
index ae91456..f84c33e 100644
--- a/components/Chat/ChatInput.tsx
+++ b/components/Chat/ChatInput.tsx
@@ -45,10 +45,8 @@ export const ChatInput: FC<Props> = ({ onSend, messageIsStreaming, model }) => {
   };
 
   const isMobile = () => {
-    const userAgent =
-      typeof window.navigator === "undefined" ? "" : navigator.userAgent;
-    const mobileRegex =
-      /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini|Mobile|mobile|CriOS/i;
+    const userAgent = typeof window.navigator === "undefined" ? "" : navigator.userAgent;
+    const mobileRegex = /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini|Mobile|mobile|CriOS/i;
     return mobileRegex.test(userAgent);
   };
 
@@ -72,12 +70,12 @@ export const ChatInput: FC<Props> = ({ onSend, messageIsStreaming, model }) => {
     <div className="fixed sm:absolute bottom-4 sm:bottom-8 w-full sm:w-1/2 px-2 left-0 sm:left-[280px] lg:left-[200px] right-0 ml-auto mr-auto">
       <textarea
         ref={textareaRef}
-        className="rounded-lg pl-4 pr-8 py-3 w-full focus:outline-none max-h-[280px] dark:bg-[#40414F] dark:border-opacity-50 dark:border-neutral-800 dark:text-neutral-100 border border-neutral-300 shadow text-neutral-900"
+        className="rounded-lg pl-4 pr-8 py-3 w-full focus:outline-none dark:bg-[#40414F] dark:border-opacity-50 dark:border-neutral-800 dark:text-neutral-100 border border-neutral-300 shadow text-neutral-900"
         style={{
           resize: "none",
           bottom: `${textareaRef?.current?.scrollHeight}px`,
           maxHeight: "400px",
-          overflow: "auto",
+          overflow: "auto"
         }}
         placeholder="Type a message..."
         value={content}
diff --git a/components/Chat/ChatMessage.tsx b/components/Chat/ChatMessage.tsx
index dff0732..dca2e64 100644
--- a/components/Chat/ChatMessage.tsx
+++ b/components/Chat/ChatMessage.tsx
@@ -20,9 +20,7 @@ export const ChatMessage: FC<Props> = ({ message, lightMode }) => {
 
         <div className="prose dark:prose-invert mt-[-2px]">
           {message.role === "user" ? (
-            <div className="prose dark:prose-invert whitespace-pre-wrap">
-              {message.content}
-            </div>
+            <div className="prose dark:prose-invert whitespace-pre-wrap">{message.content}</div>
           ) : (
             <ReactMarkdown
               remarkPlugins={[remarkGfm]}
@@ -38,11 +36,23 @@ export const ChatMessage: FC<Props> = ({ message, lightMode }) => {
                       {...props}
                     />
                   ) : (
-                    <code className={className} {...props}>
+                    <code
+                      className={className}
+                      {...props}
+                    >
                       {children}
                     </code>
                   );
                 },
+                table({ children }) {
+                  return <table className="border-collapse border border-black dark:border-white py-1 px-3">{children}</table>;
+                },
+                th({ children }) {
+                  return <th className="border border-black dark:border-white break-words py-1 px-3 bg-gray-500 text-white">{children}</th>;
+                },
+                td({ children }) {
+                  return <td className="border border-black dark:border-white break-words py-1 px-3">{children}</td>;
+                }
               }}
             >
               {message.content}
diff --git a/components/Chat/ModelSelect.tsx b/components/Chat/ModelSelect.tsx
index e5fafeb..6633e7e 100644
--- a/components/Chat/ModelSelect.tsx
+++ b/components/Chat/ModelSelect.tsx
@@ -12,7 +12,7 @@ export const ModelSelect: FC<Props> = ({ model, models, onModelChange }) => {
     <div className="flex flex-col">
       <label className="text-left mb-2 dark:text-neutral-400 text-neutral-700">Model</label>
       <select
-        className="w-[300px] p-3 dark:text-white dark:bg-[#343541] border border-neutral-500 rounded-lg appearance-none focus:shadow-outline text-neutral-900 cursor-pointer"
+        className="w-full p-3 dark:text-white dark:bg-[#343541] border border-neutral-500 rounded-lg appearance-none focus:shadow-outline text-neutral-900 cursor-pointer"
         placeholder="Select a model"
         value={model.id}
         onChange={(e) => {
diff --git a/components/Chat/SystemPrompt.tsx b/components/Chat/SystemPrompt.tsx
new file mode 100644
index 0000000..09d459e
--- /dev/null
+++ b/components/Chat/SystemPrompt.tsx
@@ -0,0 +1,65 @@
+import { Conversation } from "@/types";
+import { DEFAULT_SYSTEM_PROMPT } from "@/utils/app/const";
+import { FC, useEffect, useRef, useState } from "react";
+
+interface Props {
+  conversation: Conversation;
+  onChangePrompt: (prompt: string) => void;
+}
+
+export const SystemPrompt: FC<Props> = ({ conversation, onChangePrompt }) => {
+  const [value, setValue] = useState<string>("");
+
+  const textareaRef = useRef<HTMLTextAreaElement>(null);
+
+  const handleChange = (e: React.ChangeEvent<HTMLTextAreaElement>) => {
+    const value = e.target.value;
+    const maxLength = 4000;
+
+    if (value.length > maxLength) {
+      alert(`Prompt limit is ${maxLength} characters`);
+      return;
+    }
+
+    setValue(value);
+
+    if (value.length > 0) {
+      onChangePrompt(value);
+    }
+  };
+
+  useEffect(() => {
+    if (textareaRef && textareaRef.current) {
+      textareaRef.current.style.height = "inherit";
+      textareaRef.current.style.height = `${textareaRef.current?.scrollHeight}px`;
+    }
+  }, [value]);
+
+  useEffect(() => {
+    if (conversation.prompt) {
+      setValue(conversation.prompt);
+    } else {
+      setValue(DEFAULT_SYSTEM_PROMPT);
+    }
+  }, [conversation]);
+
+  return (
+    <div className="flex flex-col">
+      <label className="text-left dark:text-neutral-400 text-neutral-700 mb-2">System Prompt</label>
+      <textarea
+        ref={textareaRef}
+        className="w-full rounded-lg px-4 py-2 focus:outline-none dark:bg-[#40414F] dark:border-opacity-50 dark:border-neutral-800 dark:text-neutral-100 border border-neutral-500 shadow text-neutral-900"
+        style={{
+          resize: "none",
+          bottom: `${textareaRef?.current?.scrollHeight}px`,
+          maxHeight: "300px",
+          overflow: "auto"
+        }}
+        placeholder="Enter a prompt"
+        value={value}
+        rows={1}
+        onChange={handleChange}
+      />
+    </div>
+  );
+};
diff --git a/components/Sidebar/Key.tsx b/components/Sidebar/Key.tsx
index 7a197bf..26fcd0c 100644
--- a/components/Sidebar/Key.tsx
+++ b/components/Sidebar/Key.tsx
@@ -19,7 +19,7 @@ export const Key: FC<Props> = ({ apiKey, onApiKeyChange }) => {
   };
 
   const handleUpdateKey = (newKey: string) => {
-    onApiKeyChange(newKey);
+    onApiKeyChange(newKey.trim());
     setIsChanging(false);
   };
 
diff --git a/components/Sidebar/Sidebar.tsx b/components/Sidebar/Sidebar.tsx
index 6d85a27..2ae3e33 100644
--- a/components/Sidebar/Sidebar.tsx
+++ b/components/Sidebar/Sidebar.tsx
@@ -1,4 +1,4 @@
-import { Conversation } from "@/types";
+import { Conversation, KeyValuePair } from "@/types";
 import { IconArrowBarLeft, IconPlus } from "@tabler/icons-react";
 import { FC, useEffect, useState } from "react";
 import { Conversations } from "./Conversations";
@@ -16,11 +16,11 @@ interface Props {
   onSelectConversation: (conversation: Conversation) => void;
   onDeleteConversation: (conversation: Conversation) => void;
   onToggleSidebar: () => void;
-  onRenameConversation: (conversation: Conversation, name: string) => void;
+  onUpdateConversation: (conversation: Conversation, data: KeyValuePair) => void;
   onApiKeyChange: (apiKey: string) => void;
 }
 
-export const Sidebar: FC<Props> = ({ loading, conversations, lightMode, selectedConversation, apiKey, onNewConversation, onToggleLightMode, onSelectConversation, onDeleteConversation, onToggleSidebar, onRenameConversation, onApiKeyChange }) => {
+export const Sidebar: FC<Props> = ({ loading, conversations, lightMode, selectedConversation, apiKey, onNewConversation, onToggleLightMode, onSelectConversation, onDeleteConversation, onToggleSidebar, onUpdateConversation, onApiKeyChange }) => {
   const [searchTerm, setSearchTerm] = useState<string>("");
   const [filteredConversations, setFilteredConversations] = useState<Conversation[]>(conversations);
 
@@ -74,7 +74,7 @@ export const Sidebar: FC<Props> = ({ loading, conversations, lightMode, selected
             setSearchTerm("");
           }}
           onRenameConversation={(conversation, name) => {
-            onRenameConversation(conversation, name);
+            onUpdateConversation(conversation, { key: "name", value: name });
             setSearchTerm("");
           }}
         />
diff --git a/pages/api/chat.ts b/pages/api/chat.ts
index c58e615..f96e0e7 100644
--- a/pages/api/chat.ts
+++ b/pages/api/chat.ts
@@ -1,4 +1,5 @@
-import { Message, OpenAIModel, OpenAIModelID } from "@/types";
+import { ChatBody, Message, OpenAIModelID } from "@/types";
+import { DEFAULT_SYSTEM_PROMPT } from "@/utils/app/const";
 import { OpenAIStream } from "@/utils/server";
 import tiktokenModel from "@dqbd/tiktoken/encoders/cl100k_base.json";
 import { init, Tiktoken } from "@dqbd/tiktoken/lite/init";
@@ -11,11 +12,7 @@ export const config = {
 
 const handler = async (req: Request): Promise<Response> => {
   try {
-    const { model, messages, key } = (await req.json()) as {
-      model: OpenAIModel;
-      messages: Message[];
-      key: string;
-    };
+    const { model, messages, key, prompt } = (await req.json()) as ChatBody;
 
     await init((imports) => WebAssembly.instantiate(wasm, imports));
     const encoding = new Tiktoken(tiktokenModel.bpe_ranks, tiktokenModel.special_tokens, tiktokenModel.pat_str);
@@ -37,7 +34,12 @@ const handler = async (req: Request): Promise<Response> => {
 
     encoding.free();
 
-    const stream = await OpenAIStream(model, key, messagesToSend);
+    let promptToSend = prompt;
+    if (!promptToSend) {
+      promptToSend = DEFAULT_SYSTEM_PROMPT;
+    }
+
+    const stream = await OpenAIStream(model, promptToSend, key, messagesToSend);
 
     return new Response(stream);
   } catch (error) {
diff --git a/pages/index.tsx b/pages/index.tsx
index 26db5eb..5cb2424 100644
--- a/pages/index.tsx
+++ b/pages/index.tsx
@@ -1,8 +1,10 @@
 import { Chat } from "@/components/Chat/Chat";
 import { Navbar } from "@/components/Mobile/Navbar";
 import { Sidebar } from "@/components/Sidebar/Sidebar";
-import { Conversation, Message, OpenAIModel, OpenAIModelID, OpenAIModels } from "@/types";
-import { cleanConversationHistory, cleanSelectedConversation } from "@/utils/app";
+import { ChatBody, Conversation, KeyValuePair, Message, OpenAIModel, OpenAIModelID, OpenAIModels } from "@/types";
+import { cleanConversationHistory, cleanSelectedConversation } from "@/utils/app/clean";
+import { DEFAULT_SYSTEM_PROMPT } from "@/utils/app/const";
+import { saveConversation, saveConversations, updateConversation } from "@/utils/app/conversation";
 import { IconArrowBarLeft, IconArrowBarRight } from "@tabler/icons-react";
 import Head from "next/head";
 import { useEffect, useState } from "react";
@@ -43,16 +45,19 @@ export default function Home() {
       setMessageIsStreaming(true);
       setMessageError(false);
 
+      const chatBody: ChatBody = {
+        model: updatedConversation.model,
+        messages: updatedConversation.messages,
+        key: apiKey,
+        prompt: updatedConversation.prompt
+      };
+
       const response = await fetch("/api/chat", {
         method: "POST",
         headers: {
           "Content-Type": "application/json"
         },
-        body: JSON.stringify({
-          model: updatedConversation.model,
-          messages: updatedConversation.messages,
-          key: apiKey
-        })
+        body: JSON.stringify(chatBody)
       });
 
       if (!response.ok) {
@@ -118,7 +123,7 @@ export default function Home() {
         }
       }
 
-      localStorage.setItem("selectedConversation", JSON.stringify(updatedConversation));
+      saveConversation(updatedConversation);
 
       const updatedConversations: Conversation[] = conversations.map((conversation) => {
         if (conversation.id === selectedConversation.id) {
@@ -134,108 +139,12 @@ export default function Home() {
 
       setConversations(updatedConversations);
 
-      localStorage.setItem("conversationHistory", JSON.stringify(updatedConversations));
+      saveConversations(updatedConversations);
 
       setMessageIsStreaming(false);
     }
   };
 
-  const handleLightMode = (mode: "dark" | "light") => {
-    setLightMode(mode);
-    localStorage.setItem("theme", mode);
-  };
-
-  const handleRenameConversation = (conversation: Conversation, name: string) => {
-    const updatedConversation = {
-      ...conversation,
-      name
-    };
-
-    const updatedConversations = conversations.map((c) => {
-      if (c.id === updatedConversation.id) {
-        return updatedConversation;
-      }
-
-      return c;
-    });
-
-    setConversations(updatedConversations);
-    localStorage.setItem("conversationHistory", JSON.stringify(updatedConversations));
-
-    setSelectedConversation(updatedConversation);
-    localStorage.setItem("selectedConversation", JSON.stringify(updatedConversation));
-  };
-
-  const handleChangeModel = (conversation: Conversation, model: OpenAIModel) => {
-    const updatedConversation = {
-      ...conversation,
-      model
-    };
-
-    const updatedConversations = conversations.map((c) => {
-      if (c.id === updatedConversation.id) {
-        return updatedConversation;
-      }
-
-      return c;
-    });
-
-    setConversations(updatedConversations);
-    localStorage.setItem("conversationHistory", JSON.stringify(updatedConversations));
-
-    setSelectedConversation(updatedConversation);
-    localStorage.setItem("selectedConversation", JSON.stringify(updatedConversation));
-  };
-
-  const handleNewConversation = () => {
-    const lastConversation = conversations[conversations.length - 1];
-
-    const newConversation: Conversation = {
-      id: lastConversation ? lastConversation.id + 1 : 1,
-      name: `Conversation ${lastConversation ? lastConversation.id + 1 : 1}`,
-      messages: [],
-      model: OpenAIModels[OpenAIModelID.GPT_3_5]
-    };
-
-    const updatedConversations = [...conversations, newConversation];
-    setConversations(updatedConversations);
-    localStorage.setItem("conversationHistory", JSON.stringify(updatedConversations));
-
-    setSelectedConversation(newConversation);
-    localStorage.setItem("selectedConversation", JSON.stringify(newConversation));
-
-    setLoading(false);
-  };
-
-  const handleSelectConversation = (conversation: Conversation) => {
-    setSelectedConversation(conversation);
-    localStorage.setItem("selectedConversation", JSON.stringify(conversation));
-  };
-
-  const handleDeleteConversation = (conversation: Conversation) => {
-    const updatedConversations = conversations.filter((c) => c.id !== conversation.id);
-    setConversations(updatedConversations);
-    localStorage.setItem("conversationHistory", JSON.stringify(updatedConversations));
-
-    if (updatedConversations.length > 0) {
-      setSelectedConversation(updatedConversations[updatedConversations.length - 1]);
-      localStorage.setItem("selectedConversation", JSON.stringify(updatedConversations[updatedConversations.length - 1]));
-    } else {
-      setSelectedConversation({
-        id: 1,
-        name: "New conversation",
-        messages: [],
-        model: OpenAIModels[OpenAIModelID.GPT_3_5]
-      });
-      localStorage.removeItem("selectedConversation");
-    }
-  };
-
-  const handleApiKeyChange = (apiKey: string) => {
-    setApiKey(apiKey);
-    localStorage.setItem("apiKey", apiKey);
-  };
-
   const fetchModels = async (key: string) => {
     const response = await fetch("/api/models", {
       method: "POST",
@@ -262,6 +171,75 @@ export default function Home() {
     setModels(data);
   };
 
+  const handleLightMode = (mode: "dark" | "light") => {
+    setLightMode(mode);
+    localStorage.setItem("theme", mode);
+  };
+
+  const handleApiKeyChange = (apiKey: string) => {
+    setApiKey(apiKey);
+    localStorage.setItem("apiKey", apiKey);
+  };
+
+  const handleSelectConversation = (conversation: Conversation) => {
+    setSelectedConversation(conversation);
+    saveConversation(conversation);
+  };
+
+  const handleNewConversation = () => {
+    const lastConversation = conversations[conversations.length - 1];
+
+    const newConversation: Conversation = {
+      id: lastConversation ? lastConversation.id + 1 : 1,
+      name: `Conversation ${lastConversation ? lastConversation.id + 1 : 1}`,
+      messages: [],
+      model: OpenAIModels[OpenAIModelID.GPT_3_5],
+      prompt: DEFAULT_SYSTEM_PROMPT
+    };
+
+    const updatedConversations = [...conversations, newConversation];
+
+    setSelectedConversation(newConversation);
+    setConversations(updatedConversations);
+
+    saveConversation(newConversation);
+    saveConversations(updatedConversations);
+
+    setLoading(false);
+  };
+
+  const handleDeleteConversation = (conversation: Conversation) => {
+    const updatedConversations = conversations.filter((c) => c.id !== conversation.id);
+    setConversations(updatedConversations);
+    saveConversations(updatedConversations);
+
+    if (updatedConversations.length > 0) {
+      setSelectedConversation(updatedConversations[updatedConversations.length - 1]);
+      saveConversation(updatedConversations[updatedConversations.length - 1]);
+    } else {
+      setSelectedConversation({
+        id: 1,
+        name: "New conversation",
+        messages: [],
+        model: OpenAIModels[OpenAIModelID.GPT_3_5],
+        prompt: DEFAULT_SYSTEM_PROMPT
+      });
+      localStorage.removeItem("selectedConversation");
+    }
+  };
+
+  const handleUpdateConversation = (conversation: Conversation, data: KeyValuePair) => {
+    const updatedConversation = {
+      ...conversation,
+      [data.key]: data.value
+    };
+
+    const { single, all } = updateConversation(updatedConversation, conversations);
+
+    setSelectedConversation(single);
+    setConversations(all);
+  };
+
   useEffect(() => {
     const theme = localStorage.getItem("theme");
     if (theme) {
@@ -294,7 +272,8 @@ export default function Home() {
         id: 1,
         name: "New conversation",
         messages: [],
-        model: OpenAIModels[OpenAIModelID.GPT_3_5]
+        model: OpenAIModels[OpenAIModelID.GPT_3_5],
+        prompt: DEFAULT_SYSTEM_PROMPT
       });
     }
 
@@ -341,7 +320,7 @@ export default function Home() {
                   onSelectConversation={handleSelectConversation}
                   onDeleteConversation={handleDeleteConversation}
                   onToggleSidebar={() => setShowSidebar(!showSidebar)}
-                  onRenameConversation={handleRenameConversation}
+                  onUpdateConversation={handleUpdateConversation}
                   onApiKeyChange={handleApiKeyChange}
                 />
 
@@ -366,7 +345,7 @@ export default function Home() {
               loading={loading}
               lightMode={lightMode}
               onSend={handleSend}
-              onModelChange={handleChangeModel}
+              onUpdateConversation={handleUpdateConversation}
             />
           </div>
         </div>
diff --git a/types/index.ts b/types/index.ts
index 05fdfe2..a81f16a 100644
--- a/types/index.ts
+++ b/types/index.ts
@@ -31,6 +31,19 @@ export interface Conversation {
   name: string;
   messages: Message[];
   model: OpenAIModel;
+  prompt: string;
+}
+
+export interface ChatBody {
+  model: OpenAIModel;
+  messages: Message[];
+  key: string;
+  prompt: string;
+}
+
+export interface KeyValuePair {
+  key: string;
+  value: any;
 }
 
 // keep track of local storage schema
diff --git a/utils/app/clean.ts b/utils/app/clean.ts
new file mode 100644
index 0000000..c64afb3
--- /dev/null
+++ b/utils/app/clean.ts
@@ -0,0 +1,52 @@
+import { Conversation, OpenAIModelID, OpenAIModels } from "@/types";
+import { DEFAULT_SYSTEM_PROMPT } from "./const";
+
+export const cleanSelectedConversation = (conversation: Conversation) => {
+  // added model for each conversation (3/20/23)
+  // added system prompt for each conversation (3/21/23)
+
+  let updatedConversation = conversation;
+
+  // check for model on each conversation
+  if (!updatedConversation.model) {
+    updatedConversation = {
+      ...updatedConversation,
+      model: OpenAIModels[OpenAIModelID.GPT_3_5]
+    };
+  }
+
+  // check for system prompt on each conversation
+  if (!updatedConversation.prompt) {
+    updatedConversation = {
+      ...updatedConversation,
+      prompt: DEFAULT_SYSTEM_PROMPT
+    };
+  }
+
+  return updatedConversation;
+};
+
+export const cleanConversationHistory = (history: Conversation[]) => {
+  // added model for each conversation (3/20/23)
+  // added system prompt for each conversation (3/21/23)
+
+  let updatedHistory = [...history];
+
+  // check for model on each conversation
+  if (!updatedHistory.every((conversation) => conversation.model)) {
+    updatedHistory = updatedHistory.map((conversation) => ({
+      ...conversation,
+      model: OpenAIModels[OpenAIModelID.GPT_3_5]
+    }));
+  }
+
+  // check for system prompt on each conversation
+  if (!updatedHistory.every((conversation) => conversation.prompt)) {
+    updatedHistory = updatedHistory.map((conversation) => ({
+      ...conversation,
+      systemPrompt: DEFAULT_SYSTEM_PROMPT
+    }));
+  }
+
+  return updatedHistory;
+};
diff --git a/utils/app/const.ts b/utils/app/const.ts
new file mode 100644
index 0000000..badac76
--- /dev/null
+++ b/utils/app/const.ts
@@ -0,0 +1 @@
+export const DEFAULT_SYSTEM_PROMPT = "You are ChatGPT, a large language model trained by OpenAI. Follow the user's instructions carefully. Respond using markdown.";
diff --git a/utils/app/conversation.ts b/utils/app/conversation.ts
new file mode 100644
index 0000000..d1f5686
--- /dev/null
+++ b/utils/app/conversation.ts
@@ -0,0 +1,27 @@
+import { Conversation } from "@/types";
+
+export const updateConversation = (updatedConversation: Conversation, allConversations: Conversation[]) => {
+  const updatedConversations = allConversations.map((c) => {
+    if (c.id === updatedConversation.id) {
+      return updatedConversation;
+    }
+
+    return c;
+  });
+
+  saveConversation(updatedConversation);
+  saveConversations(updatedConversations);
+
+  return {
+    single: updatedConversation,
+    all: updatedConversations
+  };
+};
+
+export const saveConversation = (conversation: Conversation) => {
+  localStorage.setItem("selectedConversation", JSON.stringify(conversation));
+};
+
+export const saveConversations = (conversations: Conversation[]) => {
+  localStorage.setItem("conversationHistory", JSON.stringify(conversations));
+};
diff --git a/utils/app/index.ts b/utils/app/index.ts
deleted file mode 100644
index 30a53fb..0000000
--- a/utils/app/index.ts
+++ /dev/null
@@ -1,33 +0,0 @@
-import { Conversation, OpenAIModelID, OpenAIModels } from "@/types";
-
-export const cleanConversationHistory = (history: Conversation[]) => {
-  // added model for each conversation (3/20/23)
-
-  if (history.length === 0) {
-    return history;
-  } else {
-    return history.map((conversation) => {
-      if (conversation.model) {
-        return conversation;
-      } else {
-        return {
-          ...conversation,
-          model: OpenAIModels[OpenAIModelID.GPT_3_5]
-        };
-      }
-    });
-  }
-};
-
-export const cleanSelectedConversation = (conversation: Conversation) => {
-  // added model for each conversation (3/20/23)
-
-  if (conversation.model) {
-    return conversation;
-  } else {
-    return {
-      ...conversation,
-      model: OpenAIModels[OpenAIModelID.GPT_3_5]
-    };
-  }
-};
diff --git a/utils/server/index.ts b/utils/server/index.ts
index 8ab5766..d92c1c0 100644
--- a/utils/server/index.ts
+++ b/utils/server/index.ts
@@ -1,10 +1,7 @@
 import { Message, OpenAIModel } from "@/types";
 import { createParser, ParsedEvent, ReconnectInterval } from "eventsource-parser";
 
-export const OpenAIStream = async (model: OpenAIModel, key: string, messages: Message[]) => {
-  const encoder = new TextEncoder();
-  const decoder = new TextDecoder();
-
+export const OpenAIStream = async (model: OpenAIModel, systemPrompt: string, key: string, messages: Message[]) => {
   const res = await fetch("https://api.openai.com/v1/chat/completions", {
     headers: {
       "Content-Type": "application/json",
@@ -16,7 +13,7 @@ export const OpenAIStream = async (model: OpenAIModel, key: string, messages: Me
       messages: [
         {
           role: "system",
-          content: `You are ChatGPT, a large language model trained by OpenAI. Follow the user's instructions carefully. Respond using markdown format.`
+          content: systemPrompt
         },
         ...messages
       ],
@@ -30,6 +27,9 @@ export const OpenAIStream = async (model: OpenAIModel, key: string, messages: Me
     throw new Error("OpenAI API returned an error");
   }
 
+  const encoder = new TextEncoder();
+  const decoder = new TextDecoder();
+
   const stream = new ReadableStream({
     async start(controller) {
       const onParse = (event: ParsedEvent | ReconnectInterval) => {