diff --git a/www/index.html b/www/index.html
index 99b4960..a8137cb 100644
--- a/www/index.html
+++ b/www/index.html
@@ -20,8 +20,7 @@ Distributed, end-to-end encrypted instant messaging."/>
     <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
     <link rel="icon" sizes="64x64" href="/favicon.ico" type="image/x-icon"/>
     <link rel="stylesheet" href="/res/styles/styles.css?v=0.0.0-0" type="text/css"/>
-    <script src="/res/js/locutus.js?v=0.0.0-0" type="text/javascript"></script>
-    <script src="/res/js/usimp.js?v=0.0.0-0" type="text/javascript"></script>
+    <script src="/res/js/main.js?v=0.0.0-0" type="module"></script>
     <meta http-equiv="Content-Security-Policy" content="
         default-src 'none';
         style-src 'self';
diff --git a/www/res/js/locutus.js b/www/res/js/locutus.js
deleted file mode 100644
index bd14023..0000000
--- a/www/res/js/locutus.js
+++ /dev/null
@@ -1,220 +0,0 @@
-"use strict";
-
-let main, windows;
-let defaultLocation = '/welcome';
-
-let token = "";
-let domain = "";
-let dest = "";
-
-function createWelcomeWindow() {
-    let win = document.createElement("div");
-    win.id = "welcome-win";
-
-    win.innerHTML = `
-        <h1>Welcome to Locutus!</h1>
-        <a href="#/login" class="button">Login</a>`;
-
-    while (windows.lastChild) windows.removeChild(windows.lastChild);
-    windows.appendChild(win);
-}
-
-function createChatWindow() {
-    let win = document.createElement("div");
-    win.id = "chat-win";
-
-    console.log("Creating chat window");
-
-    win.innerHTML = `
-        <div id="message-win">
-            <p>Test Message</p>
-        </div>
-        <form id="message-form">
-            <input id="message-input" name="message" placeholder="Very important message..." type="text" required>
-        </form>
-    `;
-
-
-    let messageForm = win.getElementsByTagName("form")[0];
-    messageForm.addEventListener("submit", (evt) => {
-        evt.preventDefault();
-        let messageInput = messageForm.elements['message-input'];
-
-        let message = JSON.stringify({
-            room_id: "60nc0XXDIYUh6QzX4p0rMpCdzDmxghZLZk8dLuQh628",
-            data: {
-                message: messageInput.value
-            }
-        })
-        sendEvent(message).then((evt => {
-            console.log(evt)
-        }));
-        let messageAdd = document.createElement("p");
-        messageAdd.innerHTML = `You: <strong> ${messageInput.value} </strong>`;
-        win.getElementsByTagName("div")[0].appendChild(messageAdd);
-        messageInput.value = "";
-
-    });
-
-    while (windows.lastChild) windows.removeChild(windows.lastChild);
-    windows.style.visibility = "hidden";
-    subscribeEvent();
-    main.appendChild(win);
-}
-
-async function sendEvent(message) {
-    return fetch(`${dest}/_usimp/send_event`, {
-        method: 'POST',
-        headers: {
-            'Content-Type': 'application/json',
-            'Authorization': `usimp ${token}`,
-            'From-Domain': domain,
-            'To-Domain': domain,
-        },
-        body: message
-    });
-}
-
-async function subscribeEvent() {
-    let response = await fetch(`${dest}/_usimp/subscribe`, {
-        method: 'POST',
-        headers: {
-            'To-Domain': domain,
-            'From-Domain': domain
-        },
-        body: JSON.stringify({})
-    });
-
-    if (response.status !== 200) {
-        showMessage(response.statusText);
-        await new Promise(resolve => setTimeout(resolve, 1000));
-        await subscribeEvent();
-    } else {
-        let message = await response.text();
-        addMessage(JSON.parse(message).event.data.message);
-        await subscribeEvent();
-    }
-}
-
-function addMessage(message) {
-    let messageContainer = document.getElementById("message-win");
-    let messageP = document.createElement("p");
-    messageP.innerHTML = `Not You: <strong> ${message} </strong>`;
-    messageContainer.appendChild(messageP);
-}
-
-function createLoginWindow() {
-    let win = document.createElement("div");
-    win.id = "login-win";
-
-    win.innerHTML = `
-        <h1>Login to USIMP Account</h1>
-        <form>
-            <input name="account" placeholder="Account name" type="text" required/>
-            <input name="domain" placeholder="Domain" type="text" pattern="([a-zA-Z0-9_-]+\\.)+[a-zA-Z]{2,}" required/>
-            <input name="password" placeholder="Password" type="password" required/>
-            <button type="submit">Login</button>
-        </form>`;
-
-    win.getElementsByTagName("form")[0].addEventListener("submit", (evt) => {
-        evt.preventDefault();
-        let form = evt.target;
-        for (let e of form) e.disabled = true;
-
-        for (let d of form.getElementsByTagName("div")) {
-            form.removeChild(d);
-        }
-
-        function formError(msg) {
-            let div = document.createElement("div");
-            div.classList.add("error");
-            div.innerText = msg;
-            form.appendChild(div);
-        }
-
-        usimp.lookup(form.domain.value)
-            .then(res => {
-                if (res.ok) {
-                    res.json()
-                        .then(data => {
-                            console.log(data["domain"]);
-                            let domainServer = usimp.chooseDomainServer(data["domain_servers"]);
-                            console.log(domainServer);
-                            dest = `http://${domainServer.host}:${domainServer.protocols.http}`;
-                            domain = form.elements["domain"].value
-
-                            usimp.login(domainServer, data["domain"].id, form.elements["account"].value, form.elements["password"].value)
-                                .then(res => res.json())
-                                .catch((evt) => {
-                                    console.log("Serva ded");
-                                    console.log(evt);
-                                })
-                                .then(data => {
-                                    token = data.token;
-                                    console.log(data.token);
-                                    createChatWindow();
-                                });
-                        })
-                        .catch(reason => {
-                            console.error(reason);
-                            formError("Could not communicate with USIMP domain");
-                        })
-                } else {
-                    document.getElementsByName("domain")[0].setAttribute("invalid", "invalid");
-                    formError("Invalid USIMP domain");
-                }
-            })
-            .catch(reason => {
-                document.getElementsByName("domain")[0].setAttribute("invalid", "invalid");
-                formError("Invalid USIMP domain");
-            })
-            .finally(() => {
-                for (let e of form) e.disabled = false;
-            });
-    });
-
-    while (windows.lastChild) windows.removeChild(windows.lastChild);
-    windows.appendChild(win);
-
-    document.getElementsByName("domain")[0].addEventListener("input", (evt) => {
-        evt.target.removeAttribute("invalid");
-    });
-
-    document.getElementsByName("account")[0].focus();
-}
-
-function handleHash(hash) {
-    if (hash[0] === '#') hash = hash.substr(1);
-
-    switch (hash) {
-        case "/welcome": createWelcomeWindow(); break;
-        case "/login": createLoginWindow(); break;
-        default:
-            console.warn(`Invalid url hash #${hash}`);
-            history.replaceState(null, null, `#${defaultLocation}`);
-            handleHash(defaultLocation)
-            return;
-    }
-
-    let url = new URL(document.URL);
-    url.hash = hash;
-    location.href = url.toString();
-}
-
-function handleUrl(url) {
-    handleHash(new URL(url).hash);
-}
-
-window.addEventListener("DOMContentLoaded", (evt) => {
-    main = document.getElementsByTagName("main")[0];
-    windows = document.getElementById("windows");
-
-    // Remove <noscript> tag
-    document.getElementsByTagName("noscript")[0].remove();
-
-    handleUrl(document.URL)
-});
-
-window.addEventListener("hashchange", (evt) => {
-    handleUrl(evt.newURL);
-});
diff --git a/www/res/js/main.js b/www/res/js/main.js
new file mode 100644
index 0000000..1766fa6
--- /dev/null
+++ b/www/res/js/main.js
@@ -0,0 +1,9 @@
+"use strict";
+
+import * as Locutus from "./modules/locutus.js";
+
+window.addEventListener("DOMContentLoaded", () => {
+    // Remove <noscript> tag
+    document.getElementsByTagName("noscript")[0].remove();
+    new Locutus.App();
+});
diff --git a/www/res/js/modules/locutus.js b/www/res/js/modules/locutus.js
new file mode 100644
index 0000000..91ba429
--- /dev/null
+++ b/www/res/js/modules/locutus.js
@@ -0,0 +1,214 @@
+"use strict";
+
+import * as USIMP from "./usimp.js";
+
+export class App {
+    account;
+    defaultLocation;
+    main;
+    windows;
+    session;
+
+    constructor() {
+        if (localStorage.session === undefined) {
+            this.defaultLocation = '/welcome';
+            this.account = null;
+        } else {
+            let session = JSON.parse(localStorage.session);
+            this.defaultLocation = '/';
+            this.account = session.account;
+        }
+
+        this.main = document.getElementsByTagName("main")[0];
+        this.windows = document.getElementById("windows");
+
+        window.addEventListener("hashchange", event => {
+            this.handleUrl(event.newURL);
+        });
+
+        this.handleUrl(document.URL);
+    }
+
+    setHash(hash) {
+        let url = new URL(document.URL);
+        url.hash = hash;
+        location.href = url.toString();
+    }
+
+    handleUrl(url) {
+        this.handleHash(new URL(url).hash);
+    }
+
+    handleHash(hash) {
+        console.log(hash);
+        if (hash[0] === '#') hash = hash.substr(1);
+
+        let defaultCase = () => {
+            history.replaceState(null, null, `#${this.defaultLocation}`);
+            this.handleHash(this.defaultLocation);
+        }
+
+        switch (hash) {
+            case "/":
+                if (!this.session) {
+                    return defaultCase();
+                }
+                this.hideWindows();
+                this.showMain();
+                this.removeAllWindows();
+                this.setupMain();
+                break;
+            case "/welcome":
+                this.hideMain();
+                this.showWindows();
+                this.removeAllWindows();
+                this.addWelcomeWindow();
+                break;
+            case "/login":
+                if (this.session) {
+                    return defaultCase();
+                }
+                this.hideMain();
+                this.showWindows();
+                this.removeAllWindows();
+                this.addLoginWindow();
+                break;
+            default:
+                console.warn(`Invalid url hash #${hash}`);
+                return defaultCase();
+        }
+
+        //this.setHash(hash);
+    }
+
+    login(accountName, domainName, password) {
+        return USIMP.Domain.fromName(domainName).then(domain => {
+            let session = new USIMP.Session(domain);
+            session.authenticate(accountName, password)
+                .catch((event) => {
+                    console.error(`Unable to reach domain server: ${event}`);
+                })
+                .then(() => {
+                    this.session = session;
+                    this.defaultLocation = "/";
+                    this.setHash("/");
+                });
+        });
+    }
+
+    hideMain() {
+        this.main.style.visibility = "hidden";
+    }
+
+    showMain() {
+        this.main.style.visibility = "visible";
+    }
+
+    hideWindows() {
+        this.windows.style.visibility = "hidden";
+    }
+
+    showWindows() {
+        this.windows.style.visibility = "visible";
+    }
+
+    removeAllWindows() {
+        while (this.windows.lastChild) this.windows.removeChild(this.windows.lastChild);
+    }
+
+    addWelcomeWindow() {
+        let win = document.createElement("div");
+        win.classList.add("window-welcome");
+
+        win.innerHTML = `
+            <h1>Welcome to Locutus!</h1>
+            <a href="#/login" class="button">Login</a>`;
+
+        this.windows.appendChild(win);
+    }
+
+    addMessage(message) {
+        let msg = document.createElement("div");
+        msg.classList.add("message");
+
+        msg.innerText = message;
+
+        let chat = this.main.getElementsByClassName("chat-history")[0];
+        chat.appendChild(msg);
+        chat.scrollTop = chat.scrollHeight;
+    }
+
+    addLoginWindow() {
+        let win = document.createElement("div");
+        win.classList.add("window-login");
+
+        win.innerHTML = `
+            <h1>Login to USIMP Account</h1>
+            <form>
+                <input name="account" placeholder="Account name" type="text" required/>
+                <input name="domain" placeholder="Domain" type="text" pattern="([a-zA-Z0-9_-]+\\.)+[a-zA-Z]{2,}" required/>
+                <input name="password" placeholder="Password" type="password" required/>
+                <button type="submit">Login</button>
+            </form>`;
+
+        win.getElementsByTagName("form")[0].addEventListener("submit", async (evt) => {
+            evt.preventDefault();
+            let form = evt.target;
+            for (let e of form) e.disabled = true;
+
+            for (let d of form.getElementsByTagName("div")) {
+                form.removeChild(d);
+            }
+
+            function formError(msg) {
+                let div = document.createElement("div");
+                div.classList.add("error");
+                div.innerText = msg;
+                form.appendChild(div);
+            }
+
+            this.login(form.account.value, form.domain.value, form.password.value)
+                .catch(reason => {
+                    document.getElementsByName("domain")[0].setAttribute("invalid", "invalid");
+                    formError("Invalid USIMP domain");
+                    console.error(reason);
+                })
+                .finally(() => {
+                    for (let e of form) e.disabled = false;
+                });
+        });
+
+        this.windows.appendChild(win);
+
+        document.getElementsByName("domain")[0].addEventListener("input", (event) => {
+            event.target.removeAttribute("invalid");
+        });
+
+        document.getElementsByName("account")[0].focus();
+    }
+
+    setupMain() {
+        this.main.innerHTML = `
+            <div class="chat">
+                <div class="chat-history"></div>
+                <div class="chat-input-wrapper">
+                    <input name="message" type="text"/>
+                </div>
+            </div>`;
+
+        let input = document.getElementsByName("message")[0];
+        input.addEventListener("keyup", (event) => {
+            if (event.key === "Enter" && input.value.length > 0) {
+                this.session.sendEvent("60nc0XXDIYUh6QzX4p0rMpCdzDmxghZLZk8dLuQh628", {
+                    message: input.value,
+                });
+                this.addMessage(input.value);
+                input.value = "";
+            }
+        });
+
+        this.session.subscribe(response => {
+            this.addMessage(response.event.data.message);
+        });
+    }
+}
diff --git a/www/res/js/modules/usimp.js b/www/res/js/modules/usimp.js
new file mode 100644
index 0000000..bb9c87a
--- /dev/null
+++ b/www/res/js/modules/usimp.js
@@ -0,0 +1,204 @@
+"use strict";
+
+export class Domain {
+    name;
+    id;
+    servers;
+    invalidServers;
+
+    toString() {
+        return `[${this.name}]`;
+    }
+
+    constructor(jsonData, domainServers) {
+        // FIXME check values
+        this.name = jsonData.name;
+        this.id = jsonData.id;
+        this.servers = [];
+        for (let domainServer of domainServers) {
+            this.servers.push(new DomainServer(domainServer));
+        }
+        this.invalidServers = [];
+    }
+
+    static async fromName(domainName) {
+        return fetch(`https://${domainName}/.well-known/usimp.json`, {
+            redirect: "manual",
+        }).then(response => {
+            if (response.ok) {
+                return response.json();
+            } else {
+                throw "Invalid response";
+            }
+        }).then(data => {
+            return new Domain(data.domain, data.domain_servers);
+        });
+    }
+
+    chooseDomainServer() {
+        if (this.servers.length === 0) throw Error("No domain servers specified");
+
+        this.servers.filter(srv => this.invalidServers.map(srv => srv.id).includes(srv.id));
+        if (this.servers.length === 0) throw Error("No domain servers reachable");
+        if (this.servers.length === 1) return this.servers[0];
+
+        let priority = this.servers.reduce((min, srv) => Math.min(min, srv.priority), Infinity);
+        let domainServers = this.servers.filter(srv => srv.priority === priority);
+        if (domainServers.length === 1) return this.servers[0];
+
+        let totalWeight = domainServers.reduce((total, srv) => total + srv.weight, 0);
+        let w = Math.floor(Math.random() * totalWeight);
+
+        let accumulator = 0;
+        for (let srv of domainServers) {
+            accumulator += srv.weight;
+            if (w < accumulator) return srv;
+        }
+
+        throw "Domain server selection did not work correctly";
+    }
+}
+
+export class DomainServer {
+    host;
+    id;
+    priority;
+    weight;
+    protocols;
+
+    toString() {
+        return `[${this.host}/${this.priority}/${this.weight}]`;
+    }
+
+    constructor(jsonData) {
+        // FIXME check values
+        this.host = jsonData.host;
+        this.id = jsonData.id;
+        this.priority = jsonData.priority;
+        this.weight = jsonData.weight;
+        this.protocols = jsonData.protocols;
+    }
+}
+
+export class Account {
+
+}
+
+export class Member {
+
+}
+
+export class Room {
+
+}
+
+export class Event {
+
+}
+
+export class Session {
+    domain;
+    server;
+    token;
+
+    httpBaseUrl;
+    wsConnection;
+    numRequests;
+
+    constructor(domain) {
+        this.domain = domain;
+        this.server = domain.chooseDomainServer();
+        this.numRequests = 0;
+
+        const host = this.server.host;
+        const protocols = this.server.protocols;
+
+        /*
+        if ("wss" in protocols) {
+            this.wsConnection = new WebSocket(`wss://${host}:${protocols.wss}/_usimp/websocket`, ["usimp"]);
+        } else if ("ws" in protocols) {
+            this.wsConnection = new WebSocket(`ws://${host}:${protocols.ws}/_usimp/websocket`, ["usimp"])
+        }
+        */
+
+        if ("https" in protocols) {
+            this.httpBaseUrl = `https://${host}:${protocols.https}/_usimp`;
+        } else if ("http" in protocols) {
+            this.httpBaseUrl = `http://${host}:${protocols.http}/_usimp`;
+        } else {
+            throw "Domain server provides no supported transport protocols";
+        }
+    }
+
+    send(endpoint, data) {
+        this.numRequests++;
+        if (this.wsConnection) {
+            this.wsConnection.send(JSON.stringify({
+                'request_num': this.numRequests,
+                'data': data
+            }));
+        } else {
+            let headers = {
+                'Content-Type': 'application/json',
+                'To-Domain': this.domain.id,
+                'From-Domain': this.domain.id,
+            };
+            if (this.token) {
+                headers['Authorization'] = `usimp ${this.token}`;
+            }
+
+            return fetch(`${this.httpBaseUrl}/${endpoint}`, {
+                method: "POST",
+                headers: headers,
+                body: JSON.stringify(data),
+            }).then(response => {
+                return response.json();
+            });
+        }
+    }
+
+    authenticate(accountName, password) {
+        return this.send("authenticate", {
+            type: "password",
+            name: accountName,
+            password: password,
+        }).then(response => {
+            this.token = response.token;
+            return response;
+        });
+    }
+
+    sendEvent(roomId, data) {
+        return this.send("send_event", {
+            room_id: roomId,
+            data: data,
+        });
+    }
+
+    subscribe(func) {
+        this.numRequests++;
+        if (this.wsConnection) {
+            // TODO
+        } else {
+            let headers = {
+                'Content-Type': 'application/json',
+                'To-Domain': this.domain.id,
+                'From-Domain': this.domain.id,
+            };
+            if (this.token) {
+                headers['Authorization'] = `usimp ${this.token}`;
+            }
+
+            fetch(`${this.httpBaseUrl}/subscribe`, {
+                method: "POST",
+                headers: headers,
+                body: JSON.stringify({}),
+            }).then(response => {
+                return response.json();
+            }).then(response => {
+                func(response);
+                this.subscribe(func);
+            });
+        }
+    }
+}
diff --git a/www/res/js/usimp.js b/www/res/js/usimp.js
deleted file mode 100644
index 4741024..0000000
--- a/www/res/js/usimp.js
+++ /dev/null
@@ -1,49 +0,0 @@
-"use strict";
-
-let usimp = {};
-
-usimp.lookup = function (domain_name) {
-    return fetch(`https://${domain_name}/.well-known/usimp.json`, {
-        redirect: "manual",
-    });
-}
-
-usimp.chooseDomainServer = function (domainServers, invalidDomainServers = []) {
-    if (domainServers.length === 0) throw Error("No domain servers specified");
-
-    domainServers.filter(srv => invalidDomainServers.map(srv => srv.id).includes(srv.id));
-    if (domainServers.length === 0) throw Error("No domain servers reachable");
-    if (domainServers.length === 1) return domainServers[0];
-
-    let priority = domainServers.reduce((min, srv) => Math.min(min, srv.priority), Infinity);
-    domainServers = domainServers.filter(srv => srv.priority === priority);
-    if (domainServers.length === 1) return domainServers[0];
-
-    let totalWeight = domainServers.reduce((total, srv) => total + srv.weight, 0);
-    let w = Math.floor(Math.random() * totalWeight);
-
-    let accumulator = 0;
-    for (let srv of domainServers) {
-        accumulator += srv.weight;
-        if (w < accumulator) return srv;
-    }
-
-    console.warn("Domain server selection not worked correctly");
-    return domainServers[0];
-}
-
-usimp.login = function (domainServer, domain, account, password) {
-    return fetch(`http://${domainServer.host}:${domainServer.protocols.http}/_usimp/authenticate`, {
-        method: 'POST',
-        headers: {
-            'Content-Type': 'application/json',
-            'To-Domain': domain,
-            'From-Domain': domain
-        },
-        body: JSON.stringify({
-            type: "password",
-            name: account,
-            password: password,
-        }),
-    });
-}
diff --git a/www/res/styles/styles.css b/www/res/styles/styles.css
index 488b110..9c9a091 100644
--- a/www/res/styles/styles.css
+++ b/www/res/styles/styles.css
@@ -24,17 +24,10 @@ body {
     background-size: cover;
 }
 
-main {
-    max-width: 800px;
-    height: calc(100% - 2em);
-    padding: 1em;
-    box-sizing: border-box;
-    margin: 0 auto;
-}
-
 div#wrapper {
     box-sizing: border-box;
     width: 100%;
+    padding: 1em;
     height: calc(100vh - var(--footer-height));
 }
 
@@ -59,23 +52,33 @@ div#windows {
     left: 0;
 }
 
-div#windows > * {
+div#windows > *,
+main {
     backdrop-filter: blur(32px);
     border: 1px solid var(--bg-win);
     background: var(--bg-win);
     border-radius: 4px;
-    padding: 0.5em 1em;
     box-sizing: border-box;
 }
 
-div#login-win,
-div#welcome-win {
+main {
+    max-width: 800px;
+    height: 100%;
+    margin: 0 auto;
+}
+
+div#windows > * {
+    padding: 0.5em 1em;
+}
+
+div.window-login,
+div.window-welcome {
     max-width: 650px;
     margin: calc(max(25vh, 8em) - 8em) auto 1em auto;
 }
 
-div#login-win h1,
-div#welcome-win h1 {
+div.window-login h1,
+div.window-welcome h1 {
     text-align: center;
     font-size: 1.5rem;
 }
@@ -186,3 +189,44 @@ form button:active,
 a.button:active {
     background-color: rgba(224, 224, 224, 0.75);
 }
+
+main .chat {
+    height: 100%;
+    box-sizing: border-box;
+}
+
+main .chat-history {
+    height: calc(100% - 3em);
+    overflow-y: scroll;
+    box-sizing: border-box;
+}
+
+main .chat-input-wrapper {
+    width: 100%;
+    height: 3em;
+    border-top: 1px solid var(--bg-win);
+    padding: 0.5em 1em;
+    box-sizing: border-box;
+}
+
+main .chat-input-wrapper input {
+    background-color: rgba(0,0,0,0);
+    border: 1px solid var(--bg-win);
+    border-radius: 4px;
+    width: 100%;
+    height: 100%;
+    box-sizing: border-box;
+    outline: none;
+    padding: 0.25em 1em;
+}
+
+main .chat .message {
+    margin: 1em;
+    border: 1px solid var(--bg-win);
+    border-radius: 4px;
+    padding: 0.5em 1em;
+    display: block;
+    width: fit-content;
+    width: -moz-fit-content;
+    background-color: var(--bg);
+}