Code
The HTML Editor shows your code and the page side by side. Whatever you type appears in the preview right away - headings, lists, tables, pictures and all your CSS - and a click on anything in the preview takes you to its place in the code. You can also edit the text right in the preview. That makes it quick to build landing pages, newsletters, articles and forms without installing anything.
Everything runs in your browser. Pages are not uploaded, there is no sign-up and no advertising.
Tags, attributes, entities, comments and the CSS and JavaScript inside the page in their own colors, line numbers, end tags that close by themselves, and tidy indentation at a click.
The page as the browser shows it, in a frame where scripts and on… attributes never run and links do not navigate. Check it at full width, tablet or phone size.
Click a heading or a paragraph in the preview and type: the change goes into the code, with &, < and > written as entities.
Unclosed or misnested tags, unknown elements, pictures without alt, missing files and ids used twice - each with its line.
Drag files into the editor and use them by name: <img src="logo.png">, <link rel="stylesheet" href="style.css">. They are kept with the page in your browser.
The .html file, one HTML file with every file inside, a ZIP with the files, a PDF through the print dialog, or the plain text.
Any https page (and localhost) can embed the editor with an <iframe> and ?embed=1 - no sign-up, no key. Embedded, the editor hides this text and shows a Save button. There are two ways to get the document in and out.
src= opens a file (your server must allow CORS), webhook= makes "Save" (Ctrl+S) send the document to that address. Add &token=… for an Authorization: Bearer … header and &auto to save after every change.
<iframe src="https://html.giit.ch/?embed=1&src=https://your-site.com/pages/offer.html&webhook=https://your-site.com/save.php"
allow="clipboard-write" style="width:100%;height:800px;border:0"></iframe>The webhook gets a POST with JSON { editor, event: "save", id, name, content, assets, updated }. A small PHP script that stores it:
<?php
header('Access-Control-Allow-Origin: https://html.giit.ch');
header('Access-Control-Allow-Headers: Content-Type, Authorization');
header('Access-Control-Allow-Methods: POST, OPTIONS');
if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') exit;
if (($_SERVER['HTTP_AUTHORIZATION'] ?? '') !== 'Bearer SECRET') { http_response_code(403); exit; }
$d = json_decode(file_get_contents('php://input'), true);
$name = preg_replace('/[^\w\- ]/u', '_', $d['name']);
file_put_contents(__DIR__ . "/pages/$name.html", $d['content']);
echo '{"ok":true}';The editor says htmleditor:ready, your page answers with htmleditor:load, the editor reports htmleditor:loaded, htmleditor:change on real edits and htmleditor:save when the user saves. Your page may send htmleditor:get (the current state) or htmleditor:save (press Save). Saving then goes through your own login and session.
<iframe id="ed" src="https://html.giit.ch/?embed=1" allow="clipboard-write" style="width:100%;height:800px;border:0"></iframe>
<script>
const ed = document.getElementById('ed');
const ORIGIN = 'https://html.giit.ch';
addEventListener('message', async e => {
if (e.source !== ed.contentWindow || e.origin !== ORIGIN) return;
const m = e.data;
if (m.type === 'htmleditor:ready') { // the editor is ready: hand it the document
ed.contentWindow.postMessage({
type: 'htmleditor:load',
name: 'Offer',
content: await (await fetch('/pages/offer.html')).text(),
assets: { 'logo.png': 'data:image/png;base64,…' } // optional files
}, ORIGIN);
}
if (m.type === 'htmleditor:change') document.title = '● not saved'; // a real edit
if (m.type === 'htmleditor:save') { // the user clicked "Save"
await fetch('/api/save', { method: 'POST', headers: { 'Content-Type': 'application/json' },
body: JSON.stringify({ name: m.name, content: m.content, assets: m.assets }) });
document.title = 'Saved';
}
});
// A save button on your own page: the answer comes as htmleditor:save
function saveNow() { ed.contentWindow.postMessage({ type: 'htmleditor:get' }, ORIGIN); }
</script>AI Assistant inside your page: it works in the frame too. With allow="clipboard-write" on the iframe, "Copy prompt" uses the clipboard directly (otherwise the editor falls back to the old copy command, or shows the prompt to copy by hand). A link the AI sends cannot reach an editor inside another website, so the editor tells the AI and the user to paste the AI's whole answer into the editor instead - or open the editor in a window of its own.
window.open("https://html.giit.ch/?embed=window", "htmleditor-17") opens the full editor in its own window and speaks the same messages with window.opener. Links from an AI reach it there. htmleditor:load may also carry context: { host, title, rules } - the AI prompt then says where the document belongs and follows your rules - and hook: { url, token, assets: false }, a webhook for this document only that is never stored. Closing the window with unsaved changes sends htmleditor:closing.
Hand the editor your own prompt, an address on your site and a key for this editor session. The AI dialog then shows "Connected to" your site, what you tell the AI, and the choice change the current document or make a new one; Copy prompt puts it all together. The AI posts its result with the key to your server, and your page opens it in the editor - a new document opens separately and stays in the user's browser. One key per editor session: it stays valid while the editor is open, and only while it has none the editor asks for it with htmleditor:key-request. The editor never sends the key itself and never stores it; the address must be https on your own host or a subdomain of it.
const key = async () => (await fetch('/api/ai-key.php?doc=17')).json(); // one key per editor session
const k = await key();
ed.contentWindow.postMessage({ type: 'htmleditor:load', name: 'Offer', content, ai: {
label: 'My Site', prompt: 'Keep the [[placeholders]]. Write in German.',
endpoint: 'https://your-site.com/api/ai-result.php', key: k.key } }, ORIGIN);
// remember the id from htmleditor:loaded and ignore change/save/closing with another id
// only while the editor has no key:
if (m.type === 'htmleditor:key-request') { const k = await key(); ed.contentWindow.postMessage({ type: 'htmleditor:ai', key: k.key }, ORIGIN); }
// while the editor is open, tell your server every minute; closing the editor or the page voids the key
setInterval(() => fetch('/api/ai-key.php?alive=' + k.key.slice(0, 8)), 60000);
// your server has a result (polling, SSE …): target is "current" or "new"
ed.contentWindow.postMessage({ type: 'htmleditor:load', name: 'Offer', content: draft, from: 'ai', target }, ORIGIN);<?php // api/ai-key.php - the key of this editor session of the logged-in user (your page calls it)
session_start(); // check that the user may edit this document
$key = bin2hex(random_bytes(24));
$_SESSION['ai'][hash('sha256', $key)] = ['doc' => (int)$_GET['doc'], 'seen' => time()]; // or in your database; ?alive= sets seen again
echo json_encode(['key' => $key]);
<?php // api/ai-result.php - the AI posts here (no CORS headers: AIs call it from a server)
$key = preg_replace('/^Bearer\s+/', '', $_SERVER['HTTP_AUTHORIZATION'] ?? '');
$row = find_key(hash('sha256', $key)); // your database: not voided, seen in the last 3 minutes
if (!$row) { http_response_code(401); exit('{"ok":false,"error":"key not valid"}'); }
$d = json_decode(file_get_contents('php://input', false, null, 0, 2000000), true);
save_draft($row['doc'], $d['content'], $d['target'] === 'new' ? 'new' : 'current'); // your page shows it with htmleditor:load
echo '{"ok":true}';Make keys with at least 128 random bits, store only their hash, bind each to the logged-in user, the document and this editor session, make one per session, keep it valid only while your page reports the session as open, and void it when the editor or the page closes.
The whole protocol is in llms.txt - give it to an AI and it builds the connection for your system. The LaTeX Editor and the SVG Editor work the same way with the prefixes latexeditor: and svgeditor: - latex.giit.ch, svg.giit.ch.
No. The editor runs entirely in your browser. Your pages and their files are never sent to a server, unless you set up a webhook to your own server yourself.
No. The preview shows the HTML and CSS of the page, but scripts and on… attributes never run, and links do not navigate. That keeps the editor safe with any page you open. The code keeps its scripts, so the exported page works as before.
Drag or paste them into the editor, or add them in the Files tab on the right. They are stored with the page in your browser and used by their name, for example <img src="logo.png"> or <link rel="stylesheet" href="style.css">.
Click "Export", choose PDF and click "Print / Save as PDF". In the print dialog choose "Save as PDF" as the printer.
Only in your browser. Click the folder button at the top left (My documents) to open, rename, duplicate, download or delete them. Clearing your browser's site data removes them, so download the ones you want to keep - or let the editor send them to your own server ("Save to server").
Yes, any AI - ChatGPT, Claude, Gemini, Copilot or the AI in your coding tool. Click "AI Assistant", then "Copy prompt", paste it into your AI and say what it should write. The AI answers with a link; click it and the page appears in your editor. "Undo" takes every change back.
Yes. Embed it with an iframe and exchange documents with postMessage, or let it send every saved version to your server with a webhook. See Use the editor on your own website for examples.
No. The editor is free, without ads and without sign-up.