diff --git a/.gitignore b/.gitignore
index 17bba57618..4036c5ece4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,7 +18,6 @@ node_modules
 /store.umd.js
 /yarn-error.log
 _actual*.*
-_*/
 
 /site/cypress/screenshots/
 /site/__sapper__/
diff --git a/site/.gitignore b/site/.gitignore
deleted file mode 100644
index ed567f230d..0000000000
--- a/site/.gitignore
+++ /dev/null
@@ -1,5 +0,0 @@
-.DS_Store
-node_modules
-yarn-error.log
-/cypress/screenshots/
-/__sapper__/
diff --git a/site/src/routes/repl/_components/AppControls.html b/site/src/routes/repl/_components/AppControls.html
new file mode 100644
index 0000000000..40e5c9cc20
--- /dev/null
+++ b/site/src/routes/repl/_components/AppControls.html
@@ -0,0 +1,286 @@
+<script>
+	import { createEventDispatcher } from 'svelte';
+	import ExampleSelector from './ExampleSelector.html';
+	import UserMenu from './UserMenu.html';
+	import Icon from '../../../components/icon.html';
+	import * as doNotZip from 'do-not-zip';
+	import downloadBlob from '../_utils/downloadBlob.js';
+	import { user } from '../../../user.js';
+
+	const dispatch = createEventDispatcher();
+
+	export let examples;
+	export let gist;
+	export let name;
+	export let components;
+	export let json5;
+	export let zen_mode;
+	export let bundle;
+
+	let saving = false;
+	let downloading = false;
+	let justSaved = false;
+	let justForked = false;
+
+	const isMac = typeof navigator !== 'undefined' && navigator.platform === 'MacIntel';
+
+	function wait(ms) {
+		return new Promise(f => setTimeout(f, ms));
+	}
+
+	let canSave;
+	$: canSave = !!$user && !!gist && $user.id == gist.owner.id; // comparing number and string
+
+	function handleKeydown(event) {
+		if (event.which === 83 && (isMac ? event.metaKey : event.ctrlKey)) {
+			event.preventDefault();
+			save();
+		}
+	}
+
+	function login(event) {
+		event.preventDefault();
+		const loginWindow = window.open(`${window.location.origin}/auth/login`, 'login', 'width=600,height=400');
+
+		const handleLogin = event => {
+			loginWindow.close();
+			user.set(event.data.user);
+			window.removeEventListener('message', handleLogin);
+		};
+
+		window.addEventListener('message', handleLogin);
+	}
+
+	async function fork(intentWasSave) {
+		saving = true;
+
+		try {
+			const r = await fetch(`gist/create`, {
+				method: 'POST',
+				credentials: 'include',
+				body: JSON.stringify({
+					name,
+					components,
+					json5
+				})
+			});
+
+			if (r.status < 200 || r.status >= 300) {
+				const { error } = await r.json();
+				throw new Error(`Received an HTTP ${r.status} response: ${error}`);
+			}
+
+			const gist = await r.json();
+			dispatch('forked', { gist });
+
+			if (intentWasSave) {
+				justSaved = true;
+				await wait(600);
+				justSaved = false;
+			} else {
+				justForked = true;
+				await wait(600);
+				justForked = false;
+			}
+		} catch (err) {
+			if (navigator.onLine) {
+				alert(err.message);
+			} else {
+				alert(`It looks like you're offline! Find the internet and try again`);
+			}
+		}
+
+		saving = false;
+	}
+
+	async function save() {
+		if (saving) return;
+
+		if (!canSave) {
+			fork(true);
+			return;
+		}
+
+		saving = true;
+
+		try {
+			const files = {};
+
+			// null out any deleted files
+			const set = new Set(components.map(m => `${m.name}.${m.type}`));
+			Object.keys(gist.files).forEach(file => {
+				if (/\.(html|js)$/.test(file)) {
+					if (!set.has(file)) files[file] = null;
+				}
+			});
+
+			components.forEach(module => {
+				const file = `${module.name}.${module.type}`;
+				if (!module.source.trim()) {
+					throw new Error(`GitHub does not allow saving gists with empty files - ${file}`);
+				}
+
+				if (!gist.files[files] || module.source !== gist.files[file].content) {
+					files[file] = { content: module.source };
+				}
+			});
+
+			if (!gist.files['data.json5'] || json5 !== gist.files['data.json5'].content) {
+				files['data.json5'] = { content: json5 };
+			}
+
+			// data.json has been deprecated in favour of data.json5
+			if (gist.files['data.json']) gist.files['data.json'] = null;
+
+			const r = await fetch(`gist/${gist.id}`, {
+				method: 'PATCH',
+				credentials: 'include',
+				body: JSON.stringify({
+					description: name,
+					files
+				})
+			});
+
+			if (r.status < 200 || r.status >= 300) {
+				const { error } = await r.json();
+				throw new Error(`Received an HTTP ${r.status} response: ${error}`);
+			}
+
+			const result = await r.json();
+
+			justSaved = true;
+			await wait(600);
+			justSaved = false;
+		} catch (err) {
+			if (navigator.onLine) {
+				alert(err.message);
+			} else {
+				alert(`It looks like you're offline! Find the internet and try again`);
+			}
+		}
+
+		saving = false;
+	}
+
+	async function download() {
+		downloading = true;
+
+		const files = await (await fetch('/svelte-app.json')).json();
+
+		if (bundle.imports.length > 0) {
+			const idx = files.findIndex(({ path }) => path === 'package.json');
+			const pkg = JSON.parse(files[idx].data);
+			const deps = {};
+			bundle.imports.forEach(mod => {
+				const match = /^(@[^\/]+\/)?[^@\/]+/.exec(mod);
+				deps[match[0]] = 'latest';
+			});
+			pkg.dependencies = deps;
+			files[idx].data = JSON.stringify(pkg, null, '  ');
+		}
+
+		files.push(...components.map(component => ({ path: `src/${component.name}.${component.type}`, data: component.source })));
+		files.push({
+			path: `src/main.js`, data: `import App from './App.html';
+
+var app = new App({
+	target: document.body,
+	props: ${JSON.stringify(data, null, '\t').replace(/\n/g, '\n\t')}
+});
+
+export default app;` });
+
+		downloadBlob(doNotZip.toBlob(files), 'svelte-app.zip');
+
+		downloading = false;
+	}
+</script>
+
+<svelte:window on:keydown={handleKeydown} />
+
+<div class="app-controls">
+	<div class="icon" style="position: relative; width: 3.2rem; margin-top:-.5rem">
+		<Icon name="menu" />
+	</div>
+
+	<ExampleSelector {examples} bind:name on:select />
+
+	<div style="flex: 1 0 auto" />
+	<div style="text-align: right; margin-right:.8rem">
+		{#if $user}
+			<UserMenu />
+		{:else}
+			<a class="icon" on:click={login} href="auth/login" title="Login to save">
+				<Icon name="log-in" />
+			</a>
+		{/if}
+
+		<button class="icon" on:click="{() => zen_mode = !zen_mode}" title="fullscreen editor">
+			{#if zen_mode}
+				<Icon name="close" />
+			{:else}
+				<Icon name="maximize" />
+			{/if}
+		</button>
+
+		<button class="icon" disabled={downloading} on:click={download} title="download zip file">
+			<Icon name="download" />
+		</button>
+
+		{#if $user}
+			<button class="icon" disabled="{saving || !$user}" on:click={fork} title="fork">
+				{#if justForked}
+					<Icon name="check" />
+				{:else}
+					<Icon name="git-branch" />
+				{/if}
+			</button>
+
+			<button class="icon" disabled="{saving || !$user}" on:click={save} title="save">
+				{#if justSaved}
+					<Icon name="check" />
+				{:else}
+					<Icon name="save" />
+				{/if}
+			</button>
+		{/if}
+
+		{#if gist}
+			<a class="icon" href={gist.html_url} title="link to gist">
+				<Icon name="save" />
+			</a>
+		{/if}
+	</div>
+</div>
+
+<style>
+	.app-controls {
+		position: absolute;
+		top: 0;
+		left: 0;
+		width: 100%;
+		height: var(--app-controls-h);
+		display: flex;
+		align-items: center;
+		justify-content: space-between;
+		padding: .6rem var(--side-nav);
+		background-color: var(--second);
+		color: white;
+	}
+
+	.icon {
+		padding: 0 .8rem;
+		opacity: .5;
+		transition: opacity .3s;
+	}
+
+	.icon:hover    { opacity: 1 }
+	.icon:disabled { opacity: .3 }
+
+	.icon[title^='fullscreen'] { display: none }
+
+	@media (min-width: 768px) {
+		.icon[title^='fullscreen'] { display: inline }
+	}
+
+</style>
diff --git a/site/src/routes/repl/_components/CodeMirror.html b/site/src/routes/repl/_components/CodeMirror.html
new file mode 100644
index 0000000000..fc6ce81dd2
--- /dev/null
+++ b/site/src/routes/repl/_components/CodeMirror.html
@@ -0,0 +1,224 @@
+<script>
+	import { onMount, beforeUpdate, createEventDispatcher } from 'svelte';
+
+	const dispatch = createEventDispatcher();
+
+	export let mode;
+	export let code;
+	export let readonly;
+	export let error;
+	export let errorLoc;
+	export let warningCount = 0;
+
+	let w;
+	let h;
+
+	export function resize() {
+		editor.refresh();
+	}
+
+	const modes = {
+		json: {
+			name: 'javascript',
+			json: true
+		},
+		handlebars: {
+			name: 'handlebars',
+			base: 'text/html'
+		}
+	};
+
+	const refs = {};
+	let CodeMirror;
+	let editor;
+	let updating = false;
+	let marker;
+	let error_line;
+	let destroyed = false;
+
+	$: if (CodeMirror) {
+		createEditor(mode);
+	}
+
+	$: if (editor && !updating && code != null) {
+		updating = true;
+		editor.setValue(code);
+	}
+
+	$: if (editor && w && h) {
+		editor.refresh();
+	}
+
+	$: {
+		if (marker) marker.clear();
+
+		if (errorLoc) {
+			const line = errorLoc.line - 1;
+			const ch = errorLoc.column;
+
+			marker = editor.markText({ line, ch }, { line, ch: ch + 1 }, {
+				className: 'error-loc'
+			});
+
+			error_line = line;
+		} else {
+			error_line = null;
+		}
+	}
+
+	let previous_error_line;
+	$: if (editor) {
+		if (previous_error_line != null) {
+			editor.removeLineClass(previousLine, 'wrap', 'error-line')
+		}
+
+		if (error_line && (error_line !== previous_error_line)) {
+			editor.addLineClass(error_line, 'wrap', 'error-line');
+			previous_error_line = error_line;
+		}
+	}
+
+	onMount(() => {
+		import(/* webpackChunkName: "codemirror" */ './_codemirror.js').then(mod => {
+			CodeMirror = mod.default;
+		});
+
+		return () => {
+			destroyed = true;
+			if (editor) editor.toTextArea();
+		}
+	});
+
+	beforeUpdate(() => {
+		updating = false;
+	});
+
+	function createEditor(mode) {
+		if (destroyed) return;
+
+		if (editor) {
+			editor.toTextArea();
+		}
+
+		editor = CodeMirror.fromTextArea(refs.editor, {
+			lineNumbers: true,
+			lineWrapping: true,
+			indentWithTabs: true,
+			indentUnit: 2,
+			tabSize: 2,
+			value: code,
+			mode: modes[mode] || {
+				name: mode
+			},
+			readOnly: readonly
+		});
+
+		editor.on('change', instance => {
+			if (!updating) {
+				updating = true;
+				code = instance.getValue();
+			}
+		});
+
+		editor.refresh();
+	}
+</script>
+
+<style>
+	.codemirror-container {
+		width: 100%;
+	}
+
+	.codemirror-container :global(.CodeMirror) {
+		height: 100%;
+		min-height: 60px;
+		background: var(--background);
+		font: 300 var(--code-fs)/1.7 var(--font-mono);
+		color: var(--base);
+	}
+
+	@media (min-width: 768px) {
+		.codemirror-container {
+			height: 100%;
+			border: none;
+		}
+
+		.codemirror-container :global(.CodeMirror) {
+			height: 100%;
+		}
+	}
+
+	.codemirror-container :global(.CodeMirror-gutters) {
+		padding: 0 1.6rem 0 .8rem;
+		border: none;
+	}
+
+	.codemirror-container .message {
+		position: absolute;
+		bottom: 2.4rem;
+		left: 2.4rem;
+		z-index: 20;
+	}
+
+	.codemirror-container :global(.error-loc) {
+		position: relative;
+		border-bottom: 2px solid #da106e;
+	}
+
+	.codemirror-container :global(.error-line) {
+		background-color: rgba(200, 0, 0, .05);
+	}
+
+	.loading,
+	.error {
+		text-align: center;
+		color: #999;
+		font-weight: 300;
+		margin: 2.4rem 0 0 0;
+	}
+
+	textarea { width: 100%; border: none }
+</style>
+
+<!--
+-----------------------------------------------
+	syntax-highlighting [prism]
+	NOTE
+	- just started to transfer colors from prism to codemirror
+-----------------------------------------------
+-->
+<div class='codemirror-container' bind:offsetWidth={w} bind:offsetHeight={h}>
+	<textarea tabindex='2' bind:this={refs.editor}></textarea>
+
+	{#if error}
+		<p class='error message'>
+			{#if error.loc}
+				<strong>
+					{#if error.filename}
+						<span
+							class='filename'
+							on:click="{() => dispatch('navigate', { filename: error.filename })}"
+						>{error.filename}</span>
+					{/if}
+
+					({error.loc.line}:{error.loc.column})
+				</strong>
+			{/if}
+
+			{error.message}
+		</p>
+	{:elseif warningCount > 0}
+		<p class='warning message'>
+			Compiled, but with {warningCount} {warningCount === 1 ? 'warning' : 'warnings'} — check the console for details
+		</p>
+	{/if}
+</div>
+
+{#if !CodeMirror}
+	<p class='loading'>loading editor...</p>
+{/if}
+
+<!-- TODO -->
+<!-- {:catch err}
+<p class='error'>error loading CodeMirror</p>
+{/await} -->
\ No newline at end of file
diff --git a/site/src/routes/repl/_components/ExampleSelector.html b/site/src/routes/repl/_components/ExampleSelector.html
new file mode 100644
index 0000000000..b41ff40231
--- /dev/null
+++ b/site/src/routes/repl/_components/ExampleSelector.html
@@ -0,0 +1,77 @@
+<script>
+	import { createEventDispatcher } from 'svelte';
+	import { enter } from './events.js';
+
+	export let examples;
+	export let name;
+
+	const dispatch = createEventDispatcher();
+</script>
+
+<div class='select-wrapper'>
+	<select on:change="{e => dispatch('select', { slug: e.target.value })}">
+		<option value={null} disabled>Select an example</option>
+
+		{#each examples as group}
+			<optgroup label={group.name}>
+				{#each group.examples as example}
+					<option value={example.slug}>{example.title}</option>
+				{/each}
+			</optgroup>
+		{/each}
+	</select>
+
+	<div class='visible'>
+		<span class='widther'>{name}</span>
+		<input bind:value={name} on:focus="{e => e.target.select()}" use:enter="{e => e.target.blur()}">
+	</div>
+</div>
+
+<style>
+	.select-wrapper {
+		position: relative;
+		display: block;
+		float: left;
+		margin: 0 0 0 -4rem;
+		padding: 0 0 0 4.8rem;
+		font-family: var(--font-ui);
+	}
+
+	select {
+		position: absolute;
+		left: 0;
+		top: 0;
+		width: 100%;
+		height: 100%;
+		opacity: 0;
+		cursor: pointer;
+		/* debug only */
+		/* background-color: rgba(221, 255, 205, .377); */
+		/* opacity: .5; */
+	}
+
+	.visible {
+		position: relative;
+		padding: .5rem 1.6rem .5rem .4em;
+		font-size: 1.3rem;
+	}
+
+	span {
+		color: transparent;
+	}
+
+	input {
+		position: absolute;
+		paddding: 0;
+		width: 100%;
+		height: 100%;
+		top: 0;
+		left: .4em;
+		font-size: inherit;
+		font-family: inherit;
+		color: inherit;
+		border: none;
+		background: none;
+		opacity: .7;
+	}
+</style>
\ No newline at end of file
diff --git a/site/src/routes/repl/_components/Input/ComponentSelector.html b/site/src/routes/repl/_components/Input/ComponentSelector.html
new file mode 100644
index 0000000000..ffd02a221e
--- /dev/null
+++ b/site/src/routes/repl/_components/Input/ComponentSelector.html
@@ -0,0 +1,206 @@
+<script>
+	import { createEventDispatcher } from 'svelte';
+	import Icon from '../../../../components/icon.html';
+	import { enter } from '../events.js';
+
+	const dispatch = createEventDispatcher();
+
+	export let components;
+	export let selectedComponent;
+
+	// let previous_components;
+
+	// $: {
+	// 	// bit of a hack...
+	// 	if (components !== previous_components) {
+	// 		selectedComponent = components[0];
+	// 		previous_components = components;
+	// 	}
+	// }
+
+	function selectComponent(component, selectedComponent) {
+		if (selectedComponent != component) {
+			selectedComponent.edit = false;
+		}
+
+		dispatch('select', { component });
+	}
+
+	function editTab(component, selectedComponent) {
+		if (selectedComponent === component) {
+			selectedComponent.edit = true; // TODO can we make this local state?
+		}
+	}
+
+	function closeEdit(selectedComponent) {
+		const match = /(.+)\.(html|js)$/.exec(selectedComponent.name);
+		selectedComponent.name = match ? match[1] : selectedComponent.name;
+		if (match && match[2]) selectedComponent.type = match[2];
+		selectedComponent.edit = false;
+
+		components = components; // TODO necessary?
+	}
+
+	function remove(component) {
+		let result = confirm(`Are you sure you want to delete ${component.name}.${component.type}?`);
+		if (result) dispatch('remove');
+	}
+
+	function selectInput(event) {
+		setTimeout(() => {
+			event.target.select();
+		});
+	}
+</script>
+
+<style>
+	.component-selector {
+		position: relative;
+		border-bottom: 1px solid #eee;
+	}
+
+	.file-tabs {
+		border: none;
+		padding: 0 0 0 5rem;
+		margin: 0;
+		white-space: nowrap;
+		overflow-x: auto;
+		overflow-y: hidden;
+		height: 100%;
+	}
+
+	.file-tabs button {
+		position: relative;
+		font: 300 1.2rem/1.5 var(--font-ui);
+		color: var(--second);
+		border-bottom: var(--border-w) solid transparent;
+		padding: 1.2rem 1.2rem 0.8rem 0.5rem;
+		margin: 0 0.5rem 0 0;
+	}
+
+	.file-tabs button.active {
+		border-bottom: var(--border-w) solid var(--prime);
+	}
+
+	.editable, .uneditable, .input-sizer, input {
+		display: inline-block;
+		position: relative;
+		line-height: 1;
+	}
+
+	.input-sizer {
+		color: #ccc;
+	}
+
+	input {
+		position: absolute;
+		width: 100%;
+		left: 0.5rem;
+		top: 1.2rem;
+		/* padding: 0 0.4rem; */
+		/* font-size: 1rem; */
+		font: 300 1.2rem/1.5 var(--font-ui);
+		border: none;
+		color: var(--flash);
+		outline: none;
+		line-height: 1;
+		background-color: transparent;
+	}
+
+	.editable {
+		/* margin-right: 2.4rem; */
+	}
+
+	.uneditable {
+		/* padding-left: 1.2rem; */
+	}
+
+	.remove {
+		position: absolute;
+		display: none;
+		right: .1rem;
+		top: .4rem;
+		width: 1.6rem;
+		text-align: right;
+		padding: 1.2em 0 1.2em .5em;
+		font-size: 0.8rem;
+		cursor: pointer;
+	}
+
+	.remove:hover {
+		color: var(--flash);
+	}
+
+	.file-tabs button.active .editable {
+		cursor: text;
+	}
+
+	.file-tabs button.active .remove {
+		display: inline-block;
+	}
+
+	.add-new {
+		position: absolute;
+		left: 0;
+		top: 0;
+		width: 5rem;
+		height: 100%;
+		text-align: center;
+	}
+
+	.add-new:hover {
+		color: var(--flash);
+		background-color: white;
+	}
+</style>
+
+<!-- WUT -->
+
+<div class="component-selector">
+	<div class="file-tabs" on:dblclick="{() => dispatch('create')}">
+		{#each components as component}
+			<button
+				id={component.name}
+				class:active="{component === selectedComponent}"
+				data-name={component.name}
+				on:click="{() => selectComponent(component, selectedComponent)}"
+				on:dblclick="{e => e.stopPropagation()}"
+			>
+				{#if component.name == 'App'}
+					<div class="uneditable">
+						App.html
+					</div>
+				{:else}
+					{#if component.edit}
+						<span class="input-sizer">{component.name + (/\./.test(component.name) ? '' : '.html')}</span>
+
+						<input
+							autofocus
+							bind:value={component.name}
+							on:focus={selectInput}
+							on:blur="{() => closeEdit(selectedComponent)}"
+							use:enter="{e => e.target.blur()}"
+						>
+					{:else}
+						<div
+							class="editable"
+							title="edit component name"
+							on:click="{() => editTab(component, selectedComponent)}"
+						>
+							{component.name}.{component.type}
+						</div>
+
+						<span class="remove" on:click="{() => remove(component)}">
+							<Icon name="close"/>
+							<!-- &times; -->
+						</span>
+					{/if}
+				{/if}
+			</button>
+		{/each}
+	</div>
+
+	<button class="add-new" on:click="{() => dispatch('create')}" title="add new component">
+		<Icon name="plus" />
+	</button>
+</div>
diff --git a/site/src/routes/repl/_components/Input/ModuleEditor.html b/site/src/routes/repl/_components/Input/ModuleEditor.html
new file mode 100644
index 0000000000..7dc74bdf05
--- /dev/null
+++ b/site/src/routes/repl/_components/Input/ModuleEditor.html
@@ -0,0 +1,37 @@
+<script>
+	import CodeMirror from '../CodeMirror.html';
+
+	export let selectedComponent;
+	export let error;
+	export let errorLoc;
+	export let warningCount = 0;
+</script>
+
+<style>
+	.editor-wrapper {
+		z-index: 5;
+		background: var(--back-light);
+	}
+
+	@media (min-width: 768px) {
+		.editor-wrapper {
+			/* make it easier to interact with scrollbar */
+			padding-right: 8px;
+			height: auto;
+			/* height: 100%; */
+		}
+	}
+</style>
+
+<div class="editor-wrapper">
+	{#if selectedComponent}
+		<CodeMirror
+			mode="{selectedComponent.type === 'js' ? 'javascript' : 'handlebars'}"
+			bind:code={selectedComponent.source}
+			{error}
+			{errorLoc}
+			{warningCount}
+			on:navigate
+		/>
+	{/if}
+</div>
\ No newline at end of file
diff --git a/site/src/routes/repl/_components/Input/index.html b/site/src/routes/repl/_components/Input/index.html
new file mode 100644
index 0000000000..c97f2e26b2
--- /dev/null
+++ b/site/src/routes/repl/_components/Input/index.html
@@ -0,0 +1,27 @@
+<script>
+	import ComponentSelector from './ComponentSelector.html';
+	import ModuleEditor from './ModuleEditor.html';
+
+	export let components;
+	export let selectedComponent;
+	export let sourceError;
+	export let sourceErrorLoc;
+	export let runtimeErrorLoc;
+	export let warningCount;
+</script>
+
+<ComponentSelector
+	{components}
+	bind:selectedComponent
+	on:create
+	on:remove
+	on:select
+/>
+
+<ModuleEditor
+	bind:selectedComponent
+	error={sourceError}
+	errorLoc="{sourceErrorLoc || runtimeErrorLoc}"
+	{warningCount}
+	on:navigate
+/>
\ No newline at end of file
diff --git a/site/src/routes/repl/_components/Output/Viewer.html b/site/src/routes/repl/_components/Output/Viewer.html
new file mode 100644
index 0000000000..b160277952
--- /dev/null
+++ b/site/src/routes/repl/_components/Output/Viewer.html
@@ -0,0 +1,386 @@
+<script>
+	import { onMount, createEventDispatcher } from 'svelte';
+	import getLocationFromStack from '../../_utils/getLocationFromStack.js';
+	import { decode } from 'sourcemap-codec';
+
+	const dispatch = createEventDispatcher();
+
+	export let bundle;
+	export let dom;
+	export let ssr;
+	export let data;
+	export let sourceError;
+	export let error;
+
+	const refs = {};
+	const importCache = {};
+	let pendingImports = 0;
+	let pending = false;
+
+	function fetchImport(id, curl) {
+		return new Promise((fulfil, reject) => {
+			curl([`https://bundle.run/${id}`]).then(module => {
+				importCache[id] = module;
+				fulfil(module);
+			}, err => {
+				console.error(err.stack);
+				reject(new Error(`Error loading ${id} from bundle.run`));
+			});
+		});
+	}
+
+	const namespaceSpecifier = /\*\s+as\s+(\w+)/;
+	const namedSpecifiers = /\{(.+)\}/;
+
+	function parseSpecifiers(specifiers) {
+		specifiers = specifiers.trim();
+
+		let match = namespaceSpecifier.exec(specifiers);
+		if (match) {
+			return {
+				namespace: true,
+				name: match[1]
+			};
+		}
+
+		let names = [];
+
+		specifiers = specifiers.replace(namedSpecifiers, (match, str) => {
+			names = str.split(',').map(name => {
+				const split = name.split('as');
+				const exported = split[0].trim();
+				const local = (split[1] || exported).trim();
+
+				return { local, exported };
+			});
+
+			return '';
+		});
+
+		match = /\w+/.exec(specifiers);
+
+		return {
+			namespace: false,
+			names,
+			default: match ? match[0] : null
+		};
+	}
+
+	let createComponent;
+	let init;
+
+	onMount(() => {
+		let component;
+
+		refs.child.addEventListener('load', () => {
+			const iframe = refs.child;
+			const body = iframe.contentDocument.body;
+			const evalInIframe = iframe.contentWindow.eval;
+
+			// intercept links, so that we can use #hashes inside the iframe
+			body.addEventListener('click', event => {
+				if (event.which !== 1) return;
+				if (event.metaKey || event.ctrlKey || event.shiftKey) return;
+				if (event.defaultPrevented) return;
+
+				// ensure target is a link
+				let el = event.target;
+				while (el && el.nodeName !== 'A') el = el.parentNode;
+				if (!el || el.nodeName !== 'A') return;
+
+				if (el.hasAttribute('download') || el.getAttribute('rel') === 'external' || el.target) return;
+
+				event.preventDefault();
+
+				if (el.href.startsWith(top.location.href)) {
+					const hash = el.href.replace(top.location.href, '');
+					if (hash[0] === '#') {
+						iframe.contentWindow.location.hash = hash;
+						return;
+					}
+				}
+
+				window.open(el.href, '_blank');
+			});
+
+			let promise = null;
+			let updating = false;
+
+			let toDestroy = null;
+
+			const init = () => {
+				if (sourceError) return;
+
+				const imports = [];
+
+				const missingImports = bundle.imports.filter(x => !importCache[x]);
+
+				const removeStyles = () => {
+					const styles = iframe.contentDocument.querySelectorAll('style');
+					let i = styles.length;
+					while (i--) styles[i].parentNode.removeChild(styles[i]);
+				};
+
+				const ready = () => {
+					error = null;
+
+					if (toDestroy) {
+						removeStyles();
+
+						toDestroy.$destroy();
+						toDestroy = null;
+					}
+
+					bundle.imports.forEach(x => {
+						const module = importCache[x];
+						const name = bundle.importMap.get(x);
+
+						iframe.contentWindow[name] = module;
+					});
+
+					if (ssr) { // this only gets generated if component uses lifecycle hooks
+						pending = true;
+						createHtml();
+					} else {
+						pending = false;
+						createComponent();
+					}
+				};
+
+				const createHtml = () => {
+					try {
+						evalInIframe(`${ssr.code}
+							var rendered = SvelteComponent.render(${JSON.stringify(data)});
+
+							if (rendered.css.code) {
+								var style = document.createElement('style');
+								style.textContent = rendered.css.code;
+								document.head.appendChild(style);
+							}
+
+							document.body.innerHTML = rendered.html;
+							`)
+					} catch (e) {
+						const loc = getLocationFromStack(e.stack, ssr.map);
+						if (loc) {
+							e.filename = loc.source;
+							e.loc = { line: loc.line, column: loc.column };
+						}
+
+						error = e;
+					}
+				};
+
+				const createComponent = () => {
+					// remove leftover styles from SSR renderer
+					if (ssr) removeStyles();
+
+					try {
+						evalInIframe(`${dom.code}
+							document.body.innerHTML = '';
+							window.location.hash = '';
+							window._svelteTransitionManager = null;
+
+							var component = new SvelteComponent({
+								target: document.body,
+								data: ${JSON.stringify(data)}
+							});`);
+
+						component = window.app = window.component = iframe.contentWindow.component;
+
+						// component.on('state', ({ current }) => {
+						// 	if (updating) return;
+						// 	updating = true;
+						// 	this.fire('data', { current });
+						// 	updating = false;
+						// });
+					} catch (e) {
+						// TODO show in UI
+						component = null;
+
+						const loc = getLocationFromStack(e.stack, dom.map);
+						if (loc) {
+							e.filename = loc.source;
+							e.loc = { line: loc.line, column: loc.column };
+						}
+
+						error = e;
+					}
+				};
+
+				pendingImports = missingImports.length;
+
+				if (missingImports.length) {
+					let cancelled = false;
+
+					promise = Promise.all(
+						missingImports.map(id => fetchImport(id, iframe.contentWindow.curl).then(module => {
+							pendingImports -= 1;
+							return module;
+						}))
+					);
+					promise.cancel = () => cancelled = true;
+
+					promise
+						.then(() => {
+							if (cancelled) return;
+							ready();
+						})
+						.catch(e => {
+							if (cancelled) return;
+							error = e;
+						});
+				} else {
+					ready();
+				}
+
+				run = () => {
+					pending = false;
+
+					// TODO do we need to clear out SSR HTML?
+					createComponent();
+				};
+			}
+
+			bundle_handler = bundle => {
+				if (!bundle) return; // TODO can this ever happen?
+				if (promise) promise.cancel();
+
+				toDestroy = component;
+				component = null;
+
+				if (data !== undefined) init();
+			};
+
+			data_handler = data => {
+				if (updating) return;
+
+				try {
+					if (component) {
+						error = null;
+						updating = true;
+						component.$set(data);
+						updating = false;
+					} else {
+						init();
+					}
+				} catch (e) {
+					const loc = getLocationFromStack(e.stack, bundle.map);
+					if (loc) {
+						e.filename = loc.source;
+						e.loc = { line: loc.line, column: loc.column };
+					}
+
+					error = e;
+				}
+			};
+		});
+	});
+
+	function noop(){}
+	let run = noop;
+	let bundle_handler = noop;
+	let data_handler = noop;
+
+	$: bundle_handler(bundle);
+	$: data_handler(data);
+</script>
+
+<style>
+	.iframe-container {
+		border-top: 1px solid #ccc;
+		background-color: white;
+	}
+
+	iframe {
+		width: 100%;
+		height: calc(100vh -3em);
+		/* height: calc(100vh - var(--nav-h)); */
+		border: none;
+		display: block;
+	}
+
+	@media (min-width: 768px) {
+		.iframe-container {
+			border: none;
+			height: 100%;
+		}
+
+		iframe {
+			height: 100%;
+		}
+	}
+
+	.greyed-out {
+		filter: grayscale(50%) blur(1px);
+		opacity: .25;
+	}
+
+	.overlay {
+		position: absolute;
+		top: 0;
+		width: 100%;
+		height: 100%;
+		padding: 1em;
+		pointer-events: none;
+	}
+
+	.overlay p {
+		pointer-events: all;
+	}
+
+	.pending {
+		position: absolute;
+		top: 0;
+		left: 0;
+		width: 100%;
+		height: 100%;
+		text-align: center;
+		pointer-events: all;
+	}
+
+	.pending button {
+		position: absolute;
+		margin-top: 6rem;
+	}
+</style>
+
+<div class="iframe-container">
+	<iframe title="Result" bind:this={refs.child} class="{error || pending || pendingImports ? 'greyed-out' : ''}" srcdoc='
+		<!doctype html>
+		<html>
+			<head>
+				<link rel="stylesheet" href="/repl-viewer.css">
+			</head>
+			<body>
+				<script src="/curl.js"></script>
+				<script>curl.config(&#123; dontAddFileExt: /./ });</script>
+			</body>
+		</html>
+	'></iframe>
+</div>
+
+<div class="overlay">
+	{#if error}
+		<p class="error message">
+			{#if error.loc}
+			<strong>
+				{#if error.filename}
+					<span class="filename" on:click="{() => dispatch('navigate', { filename: error.filename })}">{error.filename}</span>
+				{/if}
+
+				({error.loc.line}:{error.loc.column})
+			</strong>
+			{/if}
+
+			{error.message}
+		</p>
+	{:elseif pending}
+		<div class="pending" on:click={run}>
+			<button class="bg-second white">Click to run</button>
+		</div>
+	{:elseif pendingImports}
+		<p class="info message">loading {pendingImports} {pendingImports === 1 ? 'dependency' : 'dependencies'} from
+		https://bundle.run</p>
+	{/if}
+</div>
\ No newline at end of file
diff --git a/site/src/routes/repl/_components/Output/index.html b/site/src/routes/repl/_components/Output/index.html
new file mode 100644
index 0000000000..2f0775891d
--- /dev/null
+++ b/site/src/routes/repl/_components/Output/index.html
@@ -0,0 +1,101 @@
+<script>
+	import SplitPane from '../SplitPane.html';
+	import Viewer from './Viewer.html';
+	import CodeMirror from '../CodeMirror.html';
+
+	export let bundle
+	export let compiled;
+	export let dom;
+	export let ssr;
+	export let data;
+	export let json5;
+	export let sourceError;
+	export let runtimeError;
+	export let dataError;
+	export let dataErrorLoc;
+
+	let view = 'result';
+</script>
+
+<style>
+	.view-toggle {
+		height: var(--pane-controls-h);
+		border-bottom: 1px solid #eee;
+	}
+
+	button {
+		/* width: 50%;
+		height: 100%; */
+		text-align: left;
+		font: 300 1.2rem/1.5 var(--font-ui);
+		border-bottom: var(--border-w) solid transparent;
+	}
+
+	button.active {
+		border-bottom: var(--border-w) solid var(--prime);
+		color: var(--second);
+	}
+
+	div {
+		height: 100%;
+	}
+</style>
+
+<div class="view-toggle">
+	<button
+		class:active="{view === 'result'}"
+		on:click="{() => view = 'result'}"
+	>Result</button>
+
+	<button
+		class:active="{view === 'code'}"
+		on:click="{() => view = 'code'}"
+	>Compiled code</button>
+</div>
+
+
+{#if view === 'result'}
+	<SplitPane type="vertical">
+		<div slot="a">
+			{#if bundle}
+				<Viewer
+					{bundle}
+					{dom}
+					{ssr}
+					{data}
+					{sourceError}
+					bind:error={runtimeError}
+					on:data="{e => updateData(e.detail.current)}"
+					on:navigate={navigate}
+				/>
+			{:else}
+				<p class="loading">loading Svelte compiler...</p>
+			{/if}
+		</div>
+
+		<section slot="b">
+			<CodeMirror
+				mode="json"
+				bind:code={json5}
+				error={dataError}
+				errorLoc={dataErrorLoc}
+			/>
+		</section>
+	</SplitPane>
+{:else}
+	<SplitPane type="vertical">
+		<div slot="a">
+			<CodeMirror
+				mode="javascript"
+				code={compiled}
+				error={sourceError}
+				errorLoc={sourceErrorLoc}
+				readonly
+			/>
+		</div>
+
+		<section slot="b">
+			compiler options go here
+		</section>
+	</SplitPane>
+{/if}
\ No newline at end of file
diff --git a/site/src/routes/repl/_components/Repl.html b/site/src/routes/repl/_components/Repl.html
new file mode 100644
index 0000000000..449f5f1e2e
--- /dev/null
+++ b/site/src/routes/repl/_components/Repl.html
@@ -0,0 +1,272 @@
+<script>
+	import { onMount } from 'svelte';
+	import * as fleece from 'golden-fleece';
+	import SplitPane from './SplitPane.html';
+	import CodeMirror from './CodeMirror.html';
+	import Input from './Input/index.html';
+	import Output from './Output/index.html';
+
+	export let version;
+	export let components;
+	export let selectedComponent;
+	export let data;
+	export let json5;
+
+	let bundle = null;
+	let dom;
+	let ssr;
+	let sourceError = null;
+	let runtimeError = null;
+	let dataError = null;
+	let dataErrorLoc = null;
+	let warningCount = 0;
+	let compiled = '';
+	let uid = 0;
+
+	let sourceErrorLoc, runtimeErrorLoc;
+
+	let worker;
+
+	onMount(async () => {
+		worker = new Worker('/repl-worker.js');
+
+		function listener(event) {
+			switch (event.data.type) {
+				case 'version':
+					version = event.data.version;
+					break;
+
+				case 'bundled':
+					({ bundle, dom, ssr, warningCount, error: sourceError } = event.data.result);
+					runtimeError = null;
+					break;
+
+				case 'compiled':
+					compiled = event.data.result;
+					break;
+			}
+		}
+
+		worker.addEventListener('message', listener);
+
+		worker.postMessage({ type: 'init', version });
+
+		return () => {
+			worker.removeEventListener('message', listener);
+			worker.terminate();
+		};
+	});
+
+	function createComponent() {
+		const newComponent = {
+			name: uid++ ? `Component${uid}` : 'Component1',
+			type: 'html',
+			source: '',
+			edit: true
+		};
+
+		components = components.concat(newComponent);
+
+		setTimeout(() => {
+			document.getElementById(newComponent.name).scrollIntoView(false);
+			selectedComponent = newComponent;
+		});
+	}
+
+	function removeComponent() {
+		const component = selectedComponent;
+
+		if (component.name === 'App') {
+			// App.html can't be removed
+			component.source = '';
+			selectedComponent = component;
+		} else {
+			const index = components.indexOf(component);
+			if (~index) {
+				components = components.slice(0, index).concat(components.slice(index + 1));
+			} else {
+				console.error(`Could not find component! That's... odd`);
+			}
+
+			selectedComponent = components[index] || components[components.length - 1];
+		}
+	}
+
+	function updateData(current) {
+		const data = fleece.evaluate(json5);
+
+		for (const key in data) {
+			data[key] = current[key];
+		}
+
+		json5 = fleece.patch(json5, data);
+	}
+
+	function navigate(filename) {
+		const name = filename.replace(/\.html$/, '');
+
+		if (selectedComponent.name === name) return;
+		selectedComponent = components.find(c => c.name === name);
+	}
+
+	$: if (sourceError && selectedComponent) {
+		sourceErrorLoc = sourceError.filename === `${selectedComponent.name}.${selectedComponent.type}`
+			? sourceError.start
+			: null;
+	}
+
+	$: if (runtimeError && selectedComponent) {
+		runtimeErrorLoc = runtimeError.filename === `${selectedComponent.name}.${selectedComponent.type}`
+			? runtimeError.start
+			: null;
+	}
+
+	$: try {
+		data= fleece.evaluate(json5);
+		dataError = null;
+		dataErrorLoc = null;
+	} catch (err) {
+		dataError = err;
+		dataErrorLoc = err && err.loc;
+	}
+
+	$: if (worker && components.length > 0) {
+		worker.postMessage({ type: 'bundle', components });
+	}
+
+	let last_selected_component;
+	$: {
+		// slightly counterintuitively, we only want to rebundle if
+		// this is the *same* component — not if we've just selected
+		// a different one
+		// if (selectedComponent === last_selected_component) {
+		// 	if (worker && components.length > 0) {
+		// 		console.log(`2`, components);
+		// 		worker.postMessage({ type: 'bundle', components });
+		// 	}
+		// }
+
+		// recompile the currently selected component
+		if (selectedComponent) {
+			if (selectedComponent.type === 'html') {
+				worker.postMessage({ type: 'compile', component: selectedComponent });
+			} else {
+				compiled = selectedComponent.source;
+			}
+		}
+
+		last_selected_component = selectedComponent;
+	}
+</script>
+
+<style>
+	.repl-inner { height: 100% }
+
+	.repl-inner :global(section) {
+		position: relative;
+		padding: 4.2rem 0 0 0;
+		height: 100%;
+	}
+
+	.repl-inner :global(section) > :global(*):first-child {
+		position: absolute;
+		top: 0;
+		left: 0;
+		width: 100%;
+		height: 4.2rem;
+	}
+
+	.repl-inner :global(section) > :global(*):last-child {
+		width: 100%;
+		height: 100%;
+	}
+
+	.repl-inner :global(.message) {
+		position: relative;
+		border-radius: var(--border-r);
+		margin: 0;
+		padding: 1.2rem 1.6rem 1.2rem 4.4rem;
+		vertical-align: middle;
+		font: 300 1.2rem/1.7 var(--font-ui);
+		color: white;
+	}
+
+	.repl-inner :global(.message::before) {
+		content: '!';
+		position: absolute;
+		left: 1.2rem;
+		top: 1.1rem;
+		width: 1rem;
+		height: 1rem;
+		text-align: center;
+		line-height: 1;
+		padding: .4rem;
+		border-radius: 50%;
+		color: white;
+		border: .2rem solid white;
+	}
+
+	.repl-inner :global(.error.message) {
+		background-color: #da106e;
+	}
+
+	.repl-inner :global(.warning.message) {
+		background-color: #e47e0a;
+	}
+
+	.repl-inner :global(.info.message) {
+		background-color: var(--second);
+		animation: fade-in .4s .2s both;
+	}
+
+	.repl-inner :global(.error) :global(.filename) {
+		cursor: pointer;
+	}
+
+	@media (min-width: 768px) {
+		.show-if-mobile { display: none }
+
+		.repl-outer.zen-mode {
+			position: fixed;
+			width: 100%;
+			height: 100%;
+			top: 0;
+			left: 0;
+			z-index: 11;
+		}
+
+		section { height: 100% }
+	}
+</style>
+
+<div class="repl-inner">
+	<SplitPane type="horizontal">
+		<section slot=a>
+			<Input
+				{components}
+				bind:selectedComponent
+				error={sourceError}
+				errorLoc="{sourceErrorLoc || runtimeErrorLoc}"
+				{warningCount}
+				on:create={createComponent}
+				on:remove={removeComponent}
+				on:select="{e => selectedComponent = e.detail.component}"
+			/>
+		</section>
+
+		<section slot=b style='height: 100%;'>
+			<Output
+				{compiled}
+				{bundle}
+				{ssr}
+				{dom}
+				{data}
+				{json5}
+				{sourceError}
+				{runtimeError}
+				{dataError}
+				{dataErrorLoc}
+			/>
+		</section>
+	</SplitPane>
+</div>
\ No newline at end of file
diff --git a/site/src/routes/repl/_components/SplitPane.html b/site/src/routes/repl/_components/SplitPane.html
new file mode 100644
index 0000000000..8c1e618131
--- /dev/null
+++ b/site/src/routes/repl/_components/SplitPane.html
@@ -0,0 +1,160 @@
+<script>
+	import { createEventDispatcher } from 'svelte';
+
+	const dispatch = createEventDispatcher();
+
+	export let type;
+
+	const refs = {};
+	const side = type === 'horizontal' ? 'left' : 'top';
+	const dimension = type === 'horizontal' ? 'width' : 'height';
+
+	let pos = 50;
+	let dragging = false;
+
+	function setPos(event) {
+		const { top, bottom, left, right } = refs.container.getBoundingClientRect();
+
+		pos = 100 * (type === 'vertical'
+			? (event.clientY - top) / (bottom - top)
+			: (event.clientX - left) / (right - left));
+
+		dispatch('change');
+	}
+
+	function drag(node, callback) {
+		const mousedown = event => {
+			if (event.which !== 1) return;
+
+			event.preventDefault();
+
+			dragging = true;
+
+			const onmouseup = () => {
+				dragging = false;
+
+				window.removeEventListener('mousemove', callback, false);
+				window.removeEventListener('mouseup', onmouseup, false);
+			};
+
+			window.addEventListener('mousemove', callback, false);
+			window.addEventListener('mouseup', onmouseup, false);
+		}
+
+		node.addEventListener('mousedown', mousedown, false);
+
+		return {
+			destroy() {
+				node.removeEventListener('mousedown', onmousedown, false);
+			}
+		};
+	}
+</script>
+
+<style>
+	.container {
+		position: relative;
+		width: 100%;
+		height: 100%;
+	}
+
+	.pane {
+		float: left;
+		width: 100%;
+		height: 100%;
+	}
+
+	.mousecatcher {
+		position: absolute;
+		left: 0;
+		top: 0;
+		width: 100%;
+		height: 100%;
+		background: rgba(255,255,255,.01);
+	}
+
+	.divider {
+		position: absolute;
+		z-index: 10;
+		display: none;
+	}
+
+	.divider::after {
+		content: '';
+		position: absolute;
+		/* background-color: #eee; */
+		background-color: var(--second);
+	}
+
+	.horizontal {
+		padding: 0 8px;
+		width: 0;
+		height: 100%;
+		cursor: ew-resize;
+	}
+
+	.horizontal::after {
+		left: 8px;
+		top: 0;
+		width: 1px;
+		height: 100%;
+	}
+
+	.vertical {
+		padding: 8px 0;
+		width: 100%;
+		height: 0;
+		cursor: ns-resize;
+	}
+
+	.vertical::after {
+		top: 8px;
+		left: 0;
+		width: 100%;
+		height: 1px;
+	}
+
+	@media (max-width: 767px) {
+		.pane {
+			/* override divider-set dimensions */
+			width: 100% !important;
+			height: auto !important;
+		}
+	}
+
+	@media (min-width: 768px) {
+		.left, .right, .divider {
+			display: block;
+
+		}
+
+		.left, .right {
+			height: 100%;
+			float: left;
+		}
+
+		.top, .bottom {
+			position: absolute;
+			width: 100%;
+		}
+
+		.top { top: 0; }
+		.bottom { bottom: 0; }
+	}
+</style>
+
+<div class="container" bind:this={refs.container}>
+	<div class="pane" style="{dimension}: {pos}%;">
+		<slot name="a"></slot>
+	</div>
+
+	<div class="pane" style="{dimension}: {100 - pos}%;">
+		<slot name="b"></slot>
+	</div>
+
+	<div class="{type} divider" style="{side}: calc({pos}% - 8px)" use:drag={setPos}></div>
+</div>
+
+{#if dragging}
+	<div class="mousecatcher"></div>
+{/if}
\ No newline at end of file
diff --git a/site/src/routes/repl/_components/UserMenu.html b/site/src/routes/repl/_components/UserMenu.html
new file mode 100644
index 0000000000..c85264fc0d
--- /dev/null
+++ b/site/src/routes/repl/_components/UserMenu.html
@@ -0,0 +1,66 @@
+<script>
+	import { user, logout } from '../../../user.js';
+
+	let showMenu = false;
+	let name;
+
+	$: name = $user.displayName || $user.username;
+</script>
+
+<div class="user" on:mouseenter="{() => showMenu = true}" on:mouseleave="{() => showMenu = false}">
+	<span>{name}</span>
+	<img alt="{name} avatar" src="{$user.photo}">
+
+	{#if showMenu}
+		<div class="menu">
+			<button on:click={logout}>log out</button>
+		</div>
+	{/if}
+</div>
+
+<style>
+	.user {
+		position: relative;
+		float: right;
+		display: block;
+		padding: .5em 2.2em 0 .8em;
+		line-height: 1;
+		z-index: 99;
+		height: 2.5em;
+	}
+
+	span {
+		/* position: relative; padding: 0 2em 0 0; */
+		line-height: 1;
+		display: inline-block;
+		padding: .05em 0;
+		font-family: Rajdhani;
+		font-weight: 400;
+	}
+
+	img {
+		position: absolute;
+		top: .2em;
+		right: 0;
+		width: 1.6em;
+		height: 1.6em;
+		border-radius: 50%;
+	}
+
+	.menu {
+		position: absolute;
+		min-width: calc(100% + .1em);
+		background-color: #f4f4f4;
+		padding: .5em;
+		z-index: 99;
+		top: calc(2.5em - 1px);
+		border-bottom: 1px solid #eee;
+		border-left: 1px solid #eee;
+		right: 0;
+		text-align: left;
+	}
+
+	.menu button {
+		background-color: transparent;
+	}
+</style>
\ No newline at end of file
diff --git a/site/src/routes/repl/_components/_codemirror.js b/site/src/routes/repl/_components/_codemirror.js
new file mode 100644
index 0000000000..1619ab760c
--- /dev/null
+++ b/site/src/routes/repl/_components/_codemirror.js
@@ -0,0 +1,10 @@
+const CodeMirror = require('codemirror');
+require('./codemirror.css');
+require('codemirror/mode/javascript/javascript.js');
+require('codemirror/mode/shell/shell.js');
+require('codemirror/mode/handlebars/handlebars.js');
+require('codemirror/mode/htmlmixed/htmlmixed.js');
+require('codemirror/mode/xml/xml.js');
+require('codemirror/mode/css/css.js');
+
+module.exports = CodeMirror;
diff --git a/site/src/routes/repl/_components/codemirror.css b/site/src/routes/repl/_components/codemirror.css
new file mode 100644
index 0000000000..299c1b444f
--- /dev/null
+++ b/site/src/routes/repl/_components/codemirror.css
@@ -0,0 +1,350 @@
+/* BASICS */
+
+.CodeMirror {
+	/* copied colors over from prism */
+	--background: var(--back-light);
+	--base:       #9b978b;
+	--comment:    #afbfcf;
+	--keyword:    #5ba3d3;
+	--function:   #db794b;
+	--string:     #b69b61;
+	--number:     #86af75;
+	--tags:       var(--function);
+	--important:  var(--string);
+
+  /* Set height, width, borders, and global font properties here */
+  /* see prism.css */
+  height: 300px;
+  direction: ltr;
+}
+
+/* PADDING */
+
+.CodeMirror-lines {
+  padding: 4px 0; /* Vertical padding around content */
+}
+.CodeMirror pre {
+  padding: 0 4px; /* Horizontal padding of content */
+}
+
+.CodeMirror-scrollbar-filler, .CodeMirror-gutter-filler {
+  background-color: white; /* The little square between H and V scrollbars */
+}
+
+/* GUTTER */
+
+.CodeMirror-gutters {
+  border-right: 1px solid #ddd;
+  background-color: #f7f7f7;
+  white-space: nowrap;
+}
+.CodeMirror-linenumber {
+  padding: 0 3px 0 5px;
+  min-width: 20px;
+  text-align: right;
+  color: var(--comment);
+  white-space: nowrap;
+  opacity: .6;
+}
+
+.CodeMirror-guttermarker { color: black; }
+.CodeMirror-guttermarker-subtle { color: #999; }
+
+/* CURSOR */
+
+.CodeMirror-cursor {
+  border-left: 1px solid black;
+  border-right: none;
+  width: 0;
+}
+/* Shown when moving in bi-directional text */
+.CodeMirror div.CodeMirror-secondarycursor {
+  border-left: 1px solid silver;
+}
+.cm-fat-cursor .CodeMirror-cursor {
+  width: auto;
+  border: 0 !important;
+  background: #7e7;
+}
+.cm-fat-cursor div.CodeMirror-cursors {
+  z-index: 1;
+}
+.cm-fat-cursor-mark {
+  background-color: rgba(20, 255, 20, .5);
+  -webkit-animation: blink 1.06s steps(1) infinite;
+  -moz-animation: blink 1.06s steps(1) infinite;
+  animation: blink 1.06s steps(1) infinite;
+}
+.cm-animate-fat-cursor {
+  width: auto;
+  border: 0;
+  -webkit-animation: blink 1.06s steps(1) infinite;
+  -moz-animation: blink 1.06s steps(1) infinite;
+  animation: blink 1.06s steps(1) infinite;
+  background-color: #7e7;
+}
+@-moz-keyframes blink {
+  0% {}
+  50% { background-color: transparent; }
+  100% {}
+}
+@-webkit-keyframes blink {
+  0% {}
+  50% { background-color: transparent; }
+  100% {}
+}
+@keyframes blink {
+  0% {}
+  50% { background-color: transparent; }
+  100% {}
+}
+
+.cm-tab { display: inline-block; text-decoration: inherit; }
+
+.CodeMirror-rulers {
+  position: absolute;
+  left: 0; right: 0; top: -50px; bottom: -20px;
+  overflow: hidden;
+}
+.CodeMirror-ruler {
+  border-left: 1px solid #ccc;
+  top: 0; bottom: 0;
+  position: absolute;
+}
+
+/* DEFAULT THEME */
+.cm-s-default .cm-header {color: blue}
+.cm-s-default .cm-quote {color: #090}
+.cm-negative {color: #d44}
+.cm-positive {color: #292}
+.cm-header, .cm-strong {font-weight: bold}
+.cm-em {font-style: italic}
+.cm-link {text-decoration: underline}
+.cm-strikethrough {text-decoration: line-through}
+
+.cm-s-default .cm-atom,
+.cm-s-default .cm-def,
+.cm-s-default .cm-property,
+.cm-s-default .cm-variable-2,
+.cm-s-default .cm-variable-3,
+.cm-s-default .cm-punctuation {color: var(--base)}
+.cm-s-default .cm-hr,
+.cm-s-default .cm-comment {color: var(--comment)}
+.cm-s-default .cm-attribute,
+.cm-s-default .cm-keyword {color: var(--keyword)}
+.cm-s-default .cm-variable,
+.cm-s-default .cm-bracket,
+.cm-s-default .cm-tag {color: var(--tags)}
+.cm-s-default .cm-number {color: var(--number)}
+.cm-s-default .cm-string {color: var(--string)}
+
+.cm-s-default .cm-string-2 {color: #f50}
+.cm-s-default .cm-type {color: #085}
+.cm-s-default .cm-meta {color: #555}
+.cm-s-default .cm-qualifier {color: #555}
+.cm-s-default .cm-builtin {color: #30a}
+.cm-s-default .cm-link {color: var(--flash)}
+.cm-s-default .cm-error {color: #ff008c}
+.cm-invalidchar {color: #ff008c}
+
+.CodeMirror-composing { border-bottom: 2px solid; }
+
+/* Default styles for common addons */
+
+div.CodeMirror span.CodeMirror-matchingbracket {color: #0b0;}
+div.CodeMirror span.CodeMirror-nonmatchingbracket {color: #a22;}
+.CodeMirror-matchingtag { background: rgba(255, 150, 0, .3); }
+.CodeMirror-activeline-background {background: #e8f2ff;}
+
+/* STOP */
+
+/* The rest of this file contains styles related to the mechanics of
+   the editor. You probably shouldn't touch them. */
+
+.CodeMirror {
+  position: relative;
+  overflow: hidden;
+  background: white;
+}
+
+.CodeMirror-scroll {
+  overflow: scroll !important; /* Things will break if this is overridden */
+  /* 30px is the magic margin used to hide the element's real scrollbars */
+  /* See overflow: hidden in .CodeMirror */
+  margin-bottom: -30px; margin-right: -30px;
+  padding-bottom: 30px;
+  height: 100%;
+  outline: none; /* Prevent dragging from highlighting the element */
+  position: relative;
+}
+.CodeMirror-sizer {
+  position: relative;
+  border-right: 30px solid transparent;
+}
+
+/* The fake, visible scrollbars. Used to force redraw during scrolling
+   before actual scrolling happens, thus preventing shaking and
+   flickering artifacts. */
+.CodeMirror-vscrollbar, .CodeMirror-hscrollbar, .CodeMirror-scrollbar-filler, .CodeMirror-gutter-filler {
+  position: absolute;
+  z-index: 6;
+  display: none;
+}
+.CodeMirror-vscrollbar {
+  right: 0; top: 0;
+  overflow-x: hidden;
+  overflow-y: scroll;
+}
+.CodeMirror-hscrollbar {
+  bottom: 0; left: 0;
+  overflow-y: hidden;
+  overflow-x: scroll;
+}
+.CodeMirror-scrollbar-filler {
+  right: 0; bottom: 0;
+}
+.CodeMirror-gutter-filler {
+  left: 0; bottom: 0;
+}
+
+.CodeMirror-gutters {
+  position: absolute; left: 0; top: 0;
+  min-height: 100%;
+  z-index: 3;
+}
+.CodeMirror-gutter {
+  white-space: normal;
+  height: 100%;
+  display: inline-block;
+  vertical-align: top;
+  margin-bottom: -30px;
+}
+.CodeMirror-gutter-wrapper {
+  position: absolute;
+  z-index: 4;
+  background: none !important;
+  border: none !important;
+}
+.CodeMirror-gutter-background {
+  position: absolute;
+  top: 0; bottom: 0;
+  z-index: 4;
+}
+.CodeMirror-gutter-elt {
+  position: absolute;
+  cursor: default;
+  z-index: 4;
+}
+.CodeMirror-gutter-wrapper ::selection { background-color: transparent }
+.CodeMirror-gutter-wrapper ::-moz-selection { background-color: transparent }
+
+.CodeMirror-lines {
+  cursor: text;
+  min-height: 1px; /* prevents collapsing before first draw */
+}
+.CodeMirror pre {
+  /* Reset some styles that the rest of the page might have set */
+  -moz-border-radius: 0; -webkit-border-radius: 0; border-radius: 0;
+  border-width: 0;
+  background: transparent;
+  font-family: inherit;
+  font-size: inherit;
+  margin: 0;
+  white-space: pre;
+  word-wrap: normal;
+  line-height: inherit;
+  color: inherit;
+  z-index: 2;
+  position: relative;
+  overflow: visible;
+  -webkit-tap-highlight-color: transparent;
+  -webkit-font-variant-ligatures: contextual;
+  font-variant-ligatures: contextual;
+}
+.CodeMirror-wrap pre {
+  word-wrap: break-word;
+  white-space: pre-wrap;
+  word-break: normal;
+}
+
+.CodeMirror-linebackground {
+  position: absolute;
+  left: 0; right: 0; top: 0; bottom: 0;
+  z-index: 0;
+}
+
+.CodeMirror-linewidget {
+  position: relative;
+  z-index: 2;
+  padding: .1px; /* Force widget margins to stay inside of the container */
+}
+
+.CodeMirror-rtl pre { direction: rtl; }
+
+.CodeMirror-code {
+  outline: none;
+}
+
+/* Force content-box sizing for the elements where we expect it */
+.CodeMirror-scroll,
+.CodeMirror-sizer,
+.CodeMirror-gutter,
+.CodeMirror-gutters,
+.CodeMirror-linenumber {
+  -moz-box-sizing: content-box;
+  box-sizing: content-box;
+}
+
+.CodeMirror-measure {
+  position: absolute;
+  width: 100%;
+  height: 0;
+  overflow: hidden;
+  visibility: hidden;
+}
+
+.CodeMirror-cursor {
+  position: absolute;
+  pointer-events: none;
+}
+.CodeMirror-measure pre { position: static; }
+
+div.CodeMirror-cursors {
+  visibility: hidden;
+  position: relative;
+  z-index: 3;
+}
+div.CodeMirror-dragcursors {
+  visibility: visible;
+}
+
+.CodeMirror-focused div.CodeMirror-cursors {
+  visibility: visible;
+}
+
+.CodeMirror-selected { background: #d9d9d9; }
+.CodeMirror-focused .CodeMirror-selected { background: #d7d4f0; }
+.CodeMirror-crosshair { cursor: crosshair; }
+.CodeMirror-line::selection, .CodeMirror-line > span::selection, .CodeMirror-line > span > span::selection { background: #d7d4f0; }
+.CodeMirror-line::-moz-selection, .CodeMirror-line > span::-moz-selection, .CodeMirror-line > span > span::-moz-selection { background: #d7d4f0; }
+
+.cm-searching {
+  background-color: #ffa;
+  background-color: rgba(255, 255, 0, .4);
+}
+
+/* Used to force a border model for a node */
+.cm-force-border { padding-right: .1px; }
+
+@media print {
+  /* Hide the cursor when printing */
+  .CodeMirror div.CodeMirror-cursors {
+    visibility: hidden;
+  }
+}
+
+/* See issue #2901 */
+.cm-tab-wrap-hack:after { content: ''; }
+
+/* Help users use markselection to safely style text background */
+span.CodeMirror-selectedtext { background: none; }
diff --git a/site/src/routes/repl/_components/component-selectors I cant find.css b/site/src/routes/repl/_components/component-selectors I cant find.css
new file mode 100644
index 0000000000..3e01d2a2bf
--- /dev/null
+++ b/site/src/routes/repl/_components/component-selectors I cant find.css	
@@ -0,0 +1,62 @@
+.module-name {
+	position: relative;
+	display: block;
+	background-color: #ff00d4;
+}
+
+.panel-header {
+	/* padding: 0 40px .5em 0; */
+	background-color: #ff00d4;
+}
+
+.dropdown {
+	position: relative;
+	display: block;
+	float: left;
+	padding: 0 2em 0 0;
+	background-color: #ff00d4;
+}
+
+.dropdown::after {
+	content: '▼';
+	position: absolute;
+	right: 1rem;
+	top: .55rem;
+	font-size: .8em;
+	color: #999;
+	pointer-events: none;
+	background-color: #ff00d4;
+}
+
+.input-wrapper {
+	position: relative;
+	display: block;
+	float: left;
+	line-height: 1;
+	/* margin: 0 .3em 0 0; */
+	background-color: #ff00d4;
+}
+
+.file-tabs li.active {
+	/* background-color: var(--back-light); */
+	background-color: #ff00d4;
+}
+
+.widther {
+	display: block;
+	font-family: inherit;
+	font-size: inherit;
+	border: 1px solid #eee;
+	padding: calc(.5em - 1px) .25em;
+	line-height: 1;
+	background-color: #ff00d4;
+}
+
+.file-extension {
+	display: inline-block;
+	padding: calc(.5em - 1px) 0;
+	color: var(--prime);
+	left: -.2em;
+	pointer-events: none;
+	background-color: #ff00d4;
+}
diff --git a/site/src/routes/repl/_components/events.js b/site/src/routes/repl/_components/events.js
new file mode 100644
index 0000000000..c1d2e84199
--- /dev/null
+++ b/site/src/routes/repl/_components/events.js
@@ -0,0 +1,19 @@
+export function keyEvent(code) {
+	return function (node, callback) {
+		node.addEventListener('keydown', handleKeydown);
+
+		function handleKeydown(event) {
+			if (event.keyCode === code) {
+				callback.call(this, event);
+			}
+		}
+
+		return {
+			destroy() {
+				node.removeEventListener('keydown', handleKeydown);
+			}
+		};
+	}
+}
+
+export const enter = keyEvent(13);
\ No newline at end of file
diff --git a/site/src/routes/repl/_utils/downloadBlob.js b/site/src/routes/repl/_utils/downloadBlob.js
new file mode 100644
index 0000000000..d90ed40530
--- /dev/null
+++ b/site/src/routes/repl/_utils/downloadBlob.js
@@ -0,0 +1,11 @@
+export default (blob, filename) => {
+	const url = URL.createObjectURL(blob);
+	const link = document.createElement('a');
+	link.href = url;
+	link.download = filename;
+	link.style.display = 'none';
+	document.body.appendChild(link);
+	link.click();
+	URL.revokeObjectURL(url);
+	link.remove();
+};
diff --git a/site/src/routes/repl/_utils/getLocationFromStack.js b/site/src/routes/repl/_utils/getLocationFromStack.js
new file mode 100644
index 0000000000..3d10fdee98
--- /dev/null
+++ b/site/src/routes/repl/_utils/getLocationFromStack.js
@@ -0,0 +1,31 @@
+import { decode } from 'sourcemap-codec';
+
+export default function getLocationFromStack(stack, map) {
+	if (!stack) return;
+	const last = stack.split('\n')[1];
+	const match = /<anonymous>:(\d+):(\d+)\)$/.exec(last);
+
+	if (!match) return null;
+
+	const line = +match[1];
+	const column = +match[2];
+
+	return trace({ line, column }, map);
+}
+
+function trace(loc, map) {
+	const mappings = decode(map.mappings);
+	const segments = mappings[loc.line - 1];
+
+	for (let i = 0; i < segments.length; i += 1) {
+		const segment = segments[i];
+		if (segment[0] === loc.column) {
+			const [, sourceIndex, line, column] = segment;
+			const source = map.sources[sourceIndex].slice(2);
+
+			return { source, line: line + 1, column };
+		}
+	}
+
+	return null;
+}