diff --git a/icons.config.ts b/icons.config.ts
index 8283e7be..bf5f777e 100644
--- a/icons.config.ts
+++ b/icons.config.ts
@@ -57,6 +57,8 @@ const config: IconsConfig = {
     "light_mode",
     "palette",
     "translate",
+    "play_arrow",
+    "extension",
   ],
   codePoints: {
     speed: "e9e4",
diff --git a/package-lock.json b/package-lock.json
index 85b3b2b3..cf0a8fd5 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -10,6 +10,8 @@
       "hasInstallScript": true,
       "license": "AGPL-3.0-or-later",
       "devDependencies": {
+        "@codemirror/lang-javascript": "^6.1.9",
+        "@codemirror/state": "^6.2.1",
         "@fontsource-variable/material-symbols-rounded": "^5.0.4",
         "@fontsource-variable/noto-sans-mono": "^5.0.4",
         "@material/material-color-utilities": "^0.2.7",
@@ -23,6 +25,7 @@
         "@types/w3c-web-serial": "^1.0.3",
         "@vite-pwa/sveltekit": "^0.2.5",
         "autoprefixer": "^10.4.14",
+        "codemirror": "^6.0.1",
         "cypress": "^12.17.1",
         "flexsearch": "^0.7.31",
         "fontkit": "^2.0.2",
@@ -1763,6 +1766,104 @@
         "node": ">=6.9.0"
       }
     },
+    "node_modules/@codemirror/autocomplete": {
+      "version": "6.9.0",
+      "resolved": "https://registry.npmjs.org/@codemirror/autocomplete/-/autocomplete-6.9.0.tgz",
+      "integrity": "sha512-Fbwm0V/Wn3BkEJZRhr0hi5BhCo5a7eBL6LYaliPjOSwCyfOpnjXY59HruSxOUNV+1OYer0Tgx1zRNQttjXyDog==",
+      "dev": true,
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.6.0",
+        "@lezer/common": "^1.0.0"
+      },
+      "peerDependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0",
+        "@lezer/common": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/commands": {
+      "version": "6.2.4",
+      "resolved": "https://registry.npmjs.org/@codemirror/commands/-/commands-6.2.4.tgz",
+      "integrity": "sha512-42lmDqVH0ttfilLShReLXsDfASKLXzfyC36bzwcqzox9PlHulMcsUOfHXNo2X2aFMVNUoQ7j+d4q5bnfseYoOA==",
+      "dev": true,
+      "dependencies": {
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/state": "^6.2.0",
+        "@codemirror/view": "^6.0.0",
+        "@lezer/common": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/lang-javascript": {
+      "version": "6.1.9",
+      "resolved": "https://registry.npmjs.org/@codemirror/lang-javascript/-/lang-javascript-6.1.9.tgz",
+      "integrity": "sha512-z3jdkcqOEBT2txn2a87A0jSy6Te3679wg/U8QzMeftFt+4KA6QooMwfdFzJiuC3L6fXKfTXZcDocoaxMYfGz0w==",
+      "dev": true,
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.0.0",
+        "@codemirror/language": "^6.6.0",
+        "@codemirror/lint": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0",
+        "@lezer/common": "^1.0.0",
+        "@lezer/javascript": "^1.0.0"
+      }
+    },
+    "node_modules/@codemirror/language": {
+      "version": "6.8.0",
+      "resolved": "https://registry.npmjs.org/@codemirror/language/-/language-6.8.0.tgz",
+      "integrity": "sha512-r1paAyWOZkfY0RaYEZj3Kul+MiQTEbDvYqf8gPGaRvNneHXCmfSaAVFjwRUPlgxS8yflMxw2CTu6uCMp8R8A2g==",
+      "dev": true,
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0",
+        "@lezer/common": "^1.0.0",
+        "@lezer/highlight": "^1.0.0",
+        "@lezer/lr": "^1.0.0",
+        "style-mod": "^4.0.0"
+      }
+    },
+    "node_modules/@codemirror/lint": {
+      "version": "6.4.0",
+      "resolved": "https://registry.npmjs.org/@codemirror/lint/-/lint-6.4.0.tgz",
+      "integrity": "sha512-6VZ44Ysh/Zn07xrGkdtNfmHCbGSHZzFBdzWi0pbd7chAQ/iUcpLGX99NYRZTa7Ugqg4kEHCqiHhcZnH0gLIgSg==",
+      "dev": true,
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0",
+        "crelt": "^1.0.5"
+      }
+    },
+    "node_modules/@codemirror/search": {
+      "version": "6.5.0",
+      "resolved": "https://registry.npmjs.org/@codemirror/search/-/search-6.5.0.tgz",
+      "integrity": "sha512-64/M40YeJPToKvGO6p3fijo2vwUEj4nACEAXElCaYQ50HrXSvRaK+NHEhSh73WFBGdvIdhrV+lL9PdJy2RfCYA==",
+      "dev": true,
+      "dependencies": {
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0",
+        "crelt": "^1.0.5"
+      }
+    },
+    "node_modules/@codemirror/state": {
+      "version": "6.2.1",
+      "resolved": "https://registry.npmjs.org/@codemirror/state/-/state-6.2.1.tgz",
+      "integrity": "sha512-RupHSZ8+OjNT38zU9fKH2sv+Dnlr8Eb8sl4NOnnqz95mCFTZUaiRP8Xv5MeeaG0px2b8Bnfe7YGwCV3nsBhbuw==",
+      "dev": true
+    },
+    "node_modules/@codemirror/view": {
+      "version": "6.16.0",
+      "resolved": "https://registry.npmjs.org/@codemirror/view/-/view-6.16.0.tgz",
+      "integrity": "sha512-1Z2HkvkC3KR/oEZVuW9Ivmp8TWLzGEd8T8TA04TTwPvqogfkHBdYSlflytDOqmkUxM2d1ywTg7X2dU5mC+SXvg==",
+      "dev": true,
+      "dependencies": {
+        "@codemirror/state": "^6.1.4",
+        "style-mod": "^4.0.0",
+        "w3c-keyname": "^2.2.4"
+      }
+    },
     "node_modules/@colors/colors": {
       "version": "1.5.0",
       "resolved": "https://registry.npmjs.org/@colors/colors/-/colors-1.5.0.tgz",
@@ -2466,6 +2567,40 @@
       "integrity": "sha512-XPSJHWmi394fuUuzDnGz1wiKqWfo1yXecHQMRf2l6hztTO+nPru658AyDngaBe7isIxEkRsPR3FZh+s7iVa4Uw==",
       "dev": true
     },
+    "node_modules/@lezer/common": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/@lezer/common/-/common-1.0.3.tgz",
+      "integrity": "sha512-JH4wAXCgUOcCGNekQPLhVeUtIqjH0yPBs7vvUdSjyQama9618IOKFJwkv2kcqdhF0my8hQEgCTEJU0GIgnahvA==",
+      "dev": true
+    },
+    "node_modules/@lezer/highlight": {
+      "version": "1.1.6",
+      "resolved": "https://registry.npmjs.org/@lezer/highlight/-/highlight-1.1.6.tgz",
+      "integrity": "sha512-cmSJYa2us+r3SePpRCjN5ymCqCPv+zyXmDl0ciWtVaNiORT/MxM7ZgOMQZADD0o51qOaOg24qc/zBViOIwAjJg==",
+      "dev": true,
+      "dependencies": {
+        "@lezer/common": "^1.0.0"
+      }
+    },
+    "node_modules/@lezer/javascript": {
+      "version": "1.4.5",
+      "resolved": "https://registry.npmjs.org/@lezer/javascript/-/javascript-1.4.5.tgz",
+      "integrity": "sha512-FmBUHz8K1V22DgjTd6SrIG9owbzOYZ1t3rY6vGEmw+e2RVBd7sqjM8uXEVRFmfxKFn1Mx2ABJehHjrN3G2ZpmA==",
+      "dev": true,
+      "dependencies": {
+        "@lezer/highlight": "^1.1.3",
+        "@lezer/lr": "^1.3.0"
+      }
+    },
+    "node_modules/@lezer/lr": {
+      "version": "1.3.9",
+      "resolved": "https://registry.npmjs.org/@lezer/lr/-/lr-1.3.9.tgz",
+      "integrity": "sha512-XPz6dzuTHlnsbA5M2DZgjflNQ+9Hi5Swhic0RULdp3oOs3rh6bqGZolosVqN/fQIT8uNiepzINJDnS39oweTHQ==",
+      "dev": true,
+      "dependencies": {
+        "@lezer/common": "^1.0.0"
+      }
+    },
     "node_modules/@material/material-color-utilities": {
       "version": "0.2.7",
       "resolved": "https://registry.npmjs.org/@material/material-color-utilities/-/material-color-utilities-0.2.7.tgz",
@@ -3999,6 +4134,21 @@
         "periscopic": "^3.1.0"
       }
     },
+    "node_modules/codemirror": {
+      "version": "6.0.1",
+      "resolved": "https://registry.npmjs.org/codemirror/-/codemirror-6.0.1.tgz",
+      "integrity": "sha512-J8j+nZ+CdWmIeFIGXEFbFPtpiYacFMDR8GlHK3IyHQJMCaVRfGx9NT+Hxivv1ckLWPvNdZqndbr/7lVhrf/Svg==",
+      "dev": true,
+      "dependencies": {
+        "@codemirror/autocomplete": "^6.0.0",
+        "@codemirror/commands": "^6.0.0",
+        "@codemirror/language": "^6.0.0",
+        "@codemirror/lint": "^6.0.0",
+        "@codemirror/search": "^6.0.0",
+        "@codemirror/state": "^6.0.0",
+        "@codemirror/view": "^6.0.0"
+      }
+    },
     "node_modules/color-convert": {
       "version": "1.9.3",
       "resolved": "https://registry.npmjs.org/color-convert/-/color-convert-1.9.3.tgz",
@@ -4117,6 +4267,12 @@
       "integrity": "sha512-dcKFX3jn0MpIaXjisoRvexIJVEKzaq7z2rZKxf+MSr9TkdmHmsU4m2lcLojrj/FHl8mk5VxMmYA+ftRkP/3oKQ==",
       "dev": true
     },
+    "node_modules/crelt": {
+      "version": "1.0.6",
+      "resolved": "https://registry.npmjs.org/crelt/-/crelt-1.0.6.tgz",
+      "integrity": "sha512-VQ2MBenTq1fWZUH9DJNGti7kKv6EeAuYr3cLwxUWhIu1baTaXh4Ib5W2CqHVqib4/MqbYGJqiL3Zb8GJZr3l4g==",
+      "dev": true
+    },
     "node_modules/cross-spawn": {
       "version": "7.0.3",
       "resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-7.0.3.tgz",
@@ -9348,6 +9504,12 @@
         "url": "https://github.com/sponsors/antfu"
       }
     },
+    "node_modules/style-mod": {
+      "version": "4.0.3",
+      "resolved": "https://registry.npmjs.org/style-mod/-/style-mod-4.0.3.tgz",
+      "integrity": "sha512-78Jv8kYJdjbvRwwijtCevYADfsI0lGzYJe4mMFdceO8l75DFFDoqBhR1jVDicDRRaX4//g1u9wKeo+ztc2h1Rw==",
+      "dev": true
+    },
     "node_modules/style-search": {
       "version": "0.1.0",
       "resolved": "https://registry.npmjs.org/style-search/-/style-search-0.1.0.tgz",
@@ -10582,6 +10744,12 @@
         }
       }
     },
+    "node_modules/w3c-keyname": {
+      "version": "2.2.8",
+      "resolved": "https://registry.npmjs.org/w3c-keyname/-/w3c-keyname-2.2.8.tgz",
+      "integrity": "sha512-dpojBhNsCNN7T82Tm7k26A6G9ML3NkhDsnw9n/eoxSRlVBB4CEtIQ/KTCLI2Fwf3ataSXRhYFkQi3SlnFwPvPQ==",
+      "dev": true
+    },
     "node_modules/w3c-xmlserializer": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/w3c-xmlserializer/-/w3c-xmlserializer-4.0.0.tgz",
diff --git a/package.json b/package.json
index 2b76b8af..da8c01eb 100644
--- a/package.json
+++ b/package.json
@@ -25,6 +25,12 @@
     "@vite-pwa/sveltekit": "^0.2.5",
     "@fontsource-variable/noto-sans-mono": "^5.0.4",
     "@fontsource-variable/material-symbols-rounded": "^5.0.4",
+    "@codemirror/state": "^6.2.1",
+    "@codemirror/commands": "^6.2.4",
+    "@codemirror/autocomplete": "^6.9.0",
+    "@codemirror/lang-javascript": "^6.1.9",
+    "@codemirror/language": "^6.8.0",
+    "codemirror": "^6.0.1",
     "stylelint": "^15.9.0",
     "stylelint-config-standard-scss": "^10.0.0",
     "stylelint-config-prettier-scss": "^1.0.0",
diff --git a/src/i18n/de/index.ts b/src/i18n/de/index.ts
index e2563cd9..d1aca2a2 100644
--- a/src/i18n/de/index.ts
+++ b/src/i18n/de/index.ts
@@ -58,6 +58,11 @@ const de = {
       TITLE: "Einstellungen",
     },
   },
+  plugin: {
+    editor: {
+      RUN: "Ausführen",
+    },
+  },
 } satisfies Translation
 
 export default de
diff --git a/src/i18n/en/index.ts b/src/i18n/en/index.ts
index e4f7918c..4d32a03e 100644
--- a/src/i18n/en/index.ts
+++ b/src/i18n/en/index.ts
@@ -56,6 +56,11 @@ const en = {
       TITLE: "Settings",
     },
   },
+  plugin: {
+    editor: {
+      RUN: "Run",
+    },
+  },
 } satisfies BaseTranslation
 
 export default en
diff --git a/src/routes/plugin/+page.svelte b/src/routes/plugin/+page.svelte
new file mode 100644
index 00000000..94e119a7
--- /dev/null
+++ b/src/routes/plugin/+page.svelte
@@ -0,0 +1,186 @@
+<script lang="ts">
+  import {KEYMAP_CODES} from "$lib/serial/keymap-codes"
+  import {onMount} from "svelte"
+  import {basicSetup, EditorView} from "codemirror"
+  import {javascript, javascriptLanguage} from "@codemirror/lang-javascript"
+  import {defaultKeymap} from "@codemirror/commands"
+  import {keymap} from "@codemirror/view"
+  import {HighlightStyle, syntaxHighlighting} from "@codemirror/language"
+  import {tags} from "@lezer/highlight"
+  import LL from "../../i18n/i18n-svelte"
+  import type {CompletionContext} from "@codemirror/autocomplete"
+  import {serialPort} from "$lib/serial/connection"
+  import type {CharaDevice} from "$lib/serial/device"
+  import examplePlugin from "./example-plugin.js?raw"
+
+  let theme = EditorView.baseTheme({
+    ".cm-editor .cm-content": {
+      fontFamily: '"Noto Sans Mono", monospace',
+    },
+    ".cm-FoldPlaceholder": {
+      backgroundColor: "var(--md-sys-color-surface-variant)",
+      color: "var(--md-sys-color-on-surface-variant)",
+    },
+    ".cm-gutters": {
+      backgroundColor: "var(--md-sys-color-surface-variant)",
+      color: "var(--md-sys-color-on-surface-variant)",
+      borderColor: "var(--md-sys-color-outline)",
+    },
+    ".cm-activeLineGutter": {
+      backgroundColor: "var(--md-sys-color-tertiary)",
+      color: "var(--md-sys-color-on-tertiary)",
+    },
+    ".cm-activeLine": {
+      backgroundColor: "transparent",
+    },
+    ".cm-cursor": {
+      borderColor: "var(--md-sys-color-on-background)",
+    },
+    ".cm-selectionBackground": {
+      background: "transparent !important",
+      backdropFilter: "invert(0.3)",
+    },
+  })
+  const highlightStyle = HighlightStyle.define(
+    [
+      {tag: tags.keyword, color: "var(--md-sys-color-primary)"},
+      {tag: tags.number, color: "var(--md-sys-color-secondary)"},
+      {tag: tags.string, color: "var(--md-sys-color-tertiary)"},
+      {tag: tags.comment, color: "var(--md-sys-color-on-background)", opacity: 0.6},
+    ],
+    {
+      all: {fontFamily: '"Noto Sans Mono", monospace', fontSize: "14px"},
+    },
+  )
+  const completion = javascriptLanguage.data.of({
+    autocomplete: function completeGlobals(context: CompletionContext) {
+      if (context.matchBefore(/Chara\./)) {
+        // TODO
+      }
+    },
+  })
+
+  onMount(() => {
+    editorView = new EditorView({
+      extensions: [
+        basicSetup,
+        javascript(),
+        keymap.of(defaultKeymap),
+        theme,
+        syntaxHighlighting(highlightStyle),
+        completion,
+      ],
+      parent: editor,
+      doc: examplePlugin,
+    })
+  })
+
+  const charaMethods = [
+    "reboot",
+    "bootloader",
+    "getRamBytesAvailable",
+    "getSetting",
+    "setSetting",
+    "getLayoutKey",
+    "setLayoutKey",
+    "deleteChord",
+    "setChord",
+    "getChordPhrase",
+    "getChordCount",
+    "getChord",
+    "send",
+  ] satisfies Array<keyof CharaDevice>
+  $: channels = $serialPort
+    ? ({
+        getVersion: async (..._args: unknown[]) => $serialPort.version,
+        getDevice: async (..._args: unknown[]) => $serialPort.device,
+        commit: async (..._args: unknown[]) => {
+          if (
+            confirm(
+              "Perform a commit? Settings are already applied until the next reboot.\n\n" +
+                "Excessive commits can lead to premature breakdowns, as the settings storage is only rated for 10,000-25,000 commits.\n\n" +
+                "Click OK to perform the commit anyways.",
+            )
+          ) {
+            return $serialPort.commit()
+          }
+        },
+        ...Object.fromEntries(charaMethods.map(it => [it, $serialPort[it].bind($serialPort)] as const)),
+      } satisfies Record<string, Function>)
+    : ({} as any)
+
+  async function onMessage(event: MessageEvent) {
+    if (event.origin !== "null" || event.source !== frame.contentWindow) return
+
+    const [channel, params] = event.data
+    const response = channels[channel as keyof typeof channels](...params)
+    frame.contentWindow!.postMessage({response: await response}, "*")
+  }
+
+  function runPlugin() {
+    frame.contentWindow?.postMessage(
+      {
+        actionCodes: KEYMAP_CODES,
+        script: editorView.state.doc.toString(),
+        charaChannels: Object.keys(channels),
+      },
+      "*",
+    )
+  }
+
+  let frame: HTMLIFrameElement
+  let editor: HTMLDivElement
+  let editorView: EditorView
+</script>
+
+<svelte:window on:message={onMessage} />
+<section>
+  <button on:click={runPlugin}><span class="icon">play_arrow</span>{$LL.plugin.editor.RUN()}</button>
+  <div class="editor-root" bind:this={editor} />
+</section>
+
+<iframe
+  aria-hidden="true"
+  title="code sandbox"
+  bind:this={frame}
+  src="/sandbox.html"
+  sandbox="allow-scripts"
+/>
+
+<style lang="scss">
+  section {
+    display: flex;
+    flex-direction: column;
+    gap: 8px;
+    width: 100%;
+  }
+
+  iframe {
+    display: none;
+  }
+
+  button {
+    cursor: pointer;
+
+    display: flex;
+    align-items: center;
+    justify-content: center;
+
+    width: min-content;
+    padding-inline-start: 0;
+    padding-inline-end: 8px;
+
+    font-size: 14px;
+    font-weight: bold;
+    color: var(--md-sys-color-on-primary);
+
+    background: var(--md-sys-color-primary);
+    border: none;
+    border-radius: 4px;
+  }
+
+  .editor-root {
+    width: 100%;
+    height: 100%;
+  }
+</style>
diff --git a/src/routes/plugin/example-plugin.js b/src/routes/plugin/example-plugin.js
new file mode 100644
index 00000000..3404f916
--- /dev/null
+++ b/src/routes/plugin/example-plugin.js
@@ -0,0 +1,31 @@
+/*******************************
+ * HOLD UP AND READ THIS FIRST *
+ *******************************
+ *
+ * Chara devices have a LIMITED number of commits.
+ * calling `Chara.commit()` can be a dangerous operation, which is why a confirmation dialog will be shown.
+ * Devices are only rated for 10,000-25,000 commits, exceeding that limit may result in premature breakdowns.
+ * `Chara.setSetting` or `Chara.setLayoutKey` is not affected by this, they last however only until the next boot.
+ *
+ * Chord writing is more forgiving, but keep in mind that excessive large-scale writing can still damage the device.
+ *
+ */
+
+const count = await Chara.getChordCount() // => 499
+const chord = await Chara.getChord(2) // => {actions: [1, 2, 3], phrase: [4, 5, 6]}
+
+const setting = await Chara.getSetting(5) // => 0
+
+// This, for example, would return all chords
+const chords = []
+for (let i = 0; i < count; i++) {
+  chords.push(await Chara.getChord(i))
+}
+
+// You can also print values to the browser console (F12)
+console.log("Chords:", chords)
+
+// You can access the actions by ID!
+Actions.SPACE // => {id: "SPACE", code: 32, icon: "space_bar", description: ...}
+Actions[32] // This also works
+Actions[0x20] // Or this!
diff --git a/static/sandbox.html b/static/sandbox.html
new file mode 100644
index 00000000..b5eb3d59
--- /dev/null
+++ b/static/sandbox.html
@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>iFrame Sandbox</title>
+  <script>
+    let ongoingRequest
+    let resolveRequest
+    let source
+    async function post(channel, args) {
+      while (ongoingRequest) {
+        await ongoingRequest
+      }
+      ongoingRequest = new Promise(resolve => {
+        resolveRequest = resolve
+        source.postMessage([channel, args], "*")
+      })
+      ongoingRequest.then(() => {
+        ongoingRequest = undefined
+      })
+      return ongoingRequest
+    }
+
+    window.addEventListener('message', event => {
+      if ("response" in event.data) {
+        resolveRequest(event.data.response)
+      } else {
+        source = event.source
+
+        var Action = event.data.actionCodes
+        Object.assign(Action, Object.fromEntries(Object.values(event.data.actionCodes).filter(it => !!it.id).map(it => [it.id, it])))
+
+        var Chara = {}
+        for (const fn of event.data.charaChannels) {
+          Chara[fn] = (...args) => post(fn, args)
+        }
+
+        eval(`(async function(){${event.data.script}})()`)
+      }
+    })
+  </script>
+</head>
+</html>
\ No newline at end of file