hatemhosny · Oct 22, 2026 · Oct 21, 2026 · Oct 21, 2026 · Oct 21, 2026 · Oct 22, 2026
diff --git a/.agents/skills/livecodes/language-support/references/languages.md b/.agents/skills/livecodes/language-support/references/languages.md
@@ -151,6 +151,7 @@ Enabled via `processors` config:
 | Haskell                     | `haskell`, `hs`, `lhs`                                                              | MicroHs (not GHC)                                     |
 | Haskell (Wasm)              | `haskell-wasm`, `hs-wasm`, `wasm.hs`, `hswasm`                                      | GHC WASM                                              |
 | Rust (Wasm)                 | `rust-wasm`, `rs-wasm`, `wasm.rs`                                                   | Rust WASM                                             |
+| Scala (Wasm)                | `scala-wasm`, `scala`, `wasm.scala`                                                 | Scala 3 compiler + Scala.js linker (WASM)             |
 | Swift (Wasm)                | `swift-wasm`, `swift`, `wasm.swift`                                                 | Swift WASM                                            |
 | Zig (Wasm)                  | `zig-wasm`, `zig`                                                                   | Zig WASM                                              |
 | V (Wasm)                    | `v-wasm`, `v`, `vlang`, `wasm.v`, `vsh`                                             | V compiler in WASM                                    |

diff --git a/README.md b/README.md
@@ -13,7 +13,7 @@ A [feature-rich](https://livecodes.io/docs/features/), open-source, **client-sid
 [![LiveCodes: npm version](https://img.shields.io/npm/v/livecodes)](https://www.npmjs.com/package/livecodes)
 [![LiveCodes: npm downloads](https://img.shields.io/npm/dm/livecodes)](https://www.npmjs.com/package/livecodes)
 [![LiveCodes: jsdelivr downloads](https://data.jsdelivr.com/v1/package/npm/livecodes/badge?style=rounded)](https://www.jsdelivr.com/package/npm/livecodes)
-[![LiveCodes: languages](https://img.shields.io/badge/languages-126-blue)](https://livecodes.io/docs/languages/)
+[![LiveCodes: languages](https://img.shields.io/badge/languages-127-blue)](https://livecodes.io/docs/languages/)
 [![LiveCodes: docs](https://img.shields.io/badge/Documentation-575757?logo=gitbook&logoColor=white)](https://livecodes.io/docs/)
 [![LiveCodes: llms.txt](https://img.shields.io/badge/llms.txt-575757?logo=googledocs&logoColor=white)](https://livecodes.io/docs/llms.txt)
 [![LiveCodes: llms-full.txt](https://img.shields.io/badge/llms--full.txt-575757?logo=googledocs&logoColor=white)](https://livecodes.io/docs/llms-full.txt)

diff --git a/docs/docs/languages/scala-wasm.mdx b/docs/docs/languages/scala-wasm.mdx
@@ -0,0 +1,145 @@
+# Scala (Wasm)
+
+[Scala](https://www.scala-lang.org/) is a statically typed language that combines functional and
+object-oriented programming. Scala 3 programs can target the JVM, JavaScript (via
+[Scala.js](https://www.scala-js.org/)) and native platforms.
+
+In LiveCodes, Scala source is compiled and linked **in the browser** by the Scala 3 compiler and the
+Scala.js linker, both compiled to WebAssembly. The program then runs in the
+[result page](../features/result.mdx). Nothing is sent to a server.
+
+:::info Note
+
+The toolchain is about 46 MB and is downloaded on the first run, which can take some time. Macros
+work but download a second compiler and about 23 MB of additional compiler IR the first time they
+are used.
+
+:::
+
+## Usage
+
+Demo:
+
+import LiveCodes from '../../src/components/LiveCodes.tsx';
+
+export const scalaConfig = {
+  activeEditor: 'script',
+  script: {
+    language: 'scala-wasm',
+    content: `@main def hello(): Unit =
+  val squares = (1 to 5).map(n => n * n)
+  println("squares: " + squares.mkString(", "))
+  println("sum: " + squares.sum)
+`,
+  },
+  mode: 'simple',
+  editor: 'auto',
+  tools: {
+    status: 'full',
+  },
+};
+
+<LiveCodes config={scalaConfig}></LiveCodes>
+
+### Standard I/O
+
+Scala code runs in the context of the result page. Standard output (e.g. `println`) is captured and
+displayed in the [console](../features/console.mdx). Standard input is passed by setting the
+`livecodes.scala.input` property in JavaScript.
+
+The input is a one-shot buffer: once it is exhausted, `readLine()` returns `null` and the typed
+`StdIn` readers throw `EOFException`. It is not an interactive terminal. The following read from the
+supplied buffer:
+
+- `scala.io.StdIn.readLine()` and the typed readers (`readInt`, `readDouble`, ...)
+- `scala.Console.in`
+- `System.in.read()` and `BufferedReader(new InputStreamReader(System.in))`
+
+`java.util.Scanner` and `scala.io.Source.stdin` have no working Scala.js implementation, and a
+parameterized `@main` method cannot be wrapped (use an object main or a parameterless `@main`).
+
+### Communication with JavaScript
+
+A few helper properties and methods are available in the browser global `livecodes.scala` object:
+
+- `livecodes.scala.input`: The standard input passed to the Scala program. It can be set before the
+  initial run, or passed to `run` for subsequent runs.
+- `livecodes.scala.loaded`: A promise that resolves when the Scala environment is ready (and rejects
+  if it fails to load). Other helpers should be used after this promise resolves.
+- `livecodes.scala.ready`: A boolean that is `true` once the environment is loaded and a run has
+  completed.
+- `livecodes.scala.output`: The standard output of the last run.
+- `livecodes.scala.error`: The compiler diagnostics or runtime error of the last run, if any.
+- `livecodes.scala.exitCode`: The exit code of the last run.
+- `livecodes.scala.run(input)`: Runs the code in the editor, optionally passing standard input, and
+  returns a promise that resolves to `{ output, error, exitCode }`.
+
+```js
+await livecodes.scala.loaded;
+const { output, error, exitCode } = await livecodes.scala.run(livecodes.scala.input);
+console.log(output);
+```
+
+## Language Info
+
+### Name
+
+`scala-wasm`
+
+### Aliases / Extensions
+
+`scala`, `scala-wasm`, `wasm.scala`
+
+### Editor
+
+`script`
+
+## Compiler
+
+The [Scala 3 compiler](https://www.scala-lang.org/) and the [Scala.js](https://www.scala-js.org/) linker compiled to WebAssembly,
+provided by [`scala-toolchain-wasm`](https://github.com/tothambrus11/scala-toolchain-wasm) and
+packaged for LiveCodes by
+[`@live-codes/scala-wasm`](https://github.com/live-codes/scala-wasm).
+
+### Version
+
+Scala 3.8.3, Scala.js 1.20.2
+
+## Code Formatting
+
+Not supported.
+
+## Limitations
+
+- `java.util.Scanner` and `scala.io.Source.stdin` are not available.
+- A parameterized `@main` method cannot read the supplied standard input.
+
+## Example Usage
+
+This example passes standard input and runs the code again on each click, using the browser global
+`livecodes.scala` (also check the code in the HTML editor):
+
+<LiveCodes template="scala" height="80vh"></LiveCodes>
+
+## Live Reload
+
+By default, new code changes are sent to the result page for re-evaluation without a full page
+reload, avoiding the need to reinitialize the Scala WebAssembly environment. This behavior can be
+disabled by adding the code comment `// __livecodes_reload__` to the Scala code, which forces a full
+page reload.
+
+This comment can be added in the
+[`hiddenContent` property of the editor](../configuration/configuration-object.mdx#markup) for
+embedded playgrounds.
+
+## Starter Template
+
+https://livecodes.io/?template=scala
+
+## Links
+
+- [Scala](https://www.scala-lang.org/)
+- [Scala 3 documentation](https://docs.scala-lang.org/)
+- [Scala.js](https://www.scala-js.org/)
+- [scala-toolchain-wasm](https://github.com/tothambrus11/scala-toolchain-wasm)
+- [@live-codes/scala-wasm](https://github.com/live-codes/scala-wasm)
diff --git a/docs/src/components/LanguageSliders.tsx b/docs/src/components/LanguageSliders.tsx
@@ -105,6 +105,7 @@ export default function Sliders() {
       { name: 'flutter', title: 'Flutter' },
       { name: 'v-wasm', title: 'V (Wasm)' },
       { name: 'rust-wasm', title: 'Rust (Wasm)' },
+      { name: 'scala-wasm', title: 'Scala (Wasm)' },
       { name: 'swift-wasm', title: 'Swift (Wasm)' },
       { name: 'haskell', title: 'Haskell' },
       { name: 'haskell-wasm', title: 'Haskell (Wasm)' },

diff --git a/docs/src/components/TemplateList.tsx b/docs/src/components/TemplateList.tsx
@@ -61,6 +61,7 @@ const templates = [
   { name: 'cpp-wasm', title: 'C++ (Wasm) Starter', thumbnail: 'cpp.svg' },
   { name: 'objc-wasm', title: 'Objective-C (Wasm) Starter', thumbnail: 'objective-c.svg' },
   { name: 'rust-wasm', title: 'Rust (Wasm) Starter', thumbnail: 'rust.svg' },
+  { name: 'scala', title: 'Scala Starter', thumbnail: 'scala.svg' },
   { name: 'swift-wasm', title: 'Swift (Wasm) Starter', thumbnail: 'swift.svg' },
   { name: 'haskell', title: 'Haskell Starter', thumbnail: 'haskell.svg' },
   { name: 'haskell-wasm', title: 'Haskell (Wasm) Starter', thumbnail: 'haskell.svg' },

diff --git a/e2e/specs/compilers.spec.ts b/e2e/specs/compilers.spec.ts
@@ -1677,6 +1677,30 @@
     );
   });
 
+  test('Scala (Wasm)', async ({ page, getTestUrl, editor }) => {
+    test.skip(editor === 'codejar', 'please fix');
+    test.slow(); // the engine downloads the toolchain and compiles WebAssembly
+
+    const code = `@main def hello(): Unit =
+  println("Hello from Scala")
+`;
+
+    // Code is passed in the URL (rather than typed) so the first run cannot race the editor.
+    await page.goto(getTestUrl({ tools: 'console|open', active: 'script', 'scala-wasm': code }));
+
+    const { app, waitForResultUpdate } = await getLoadedApp(page);
+    await waitForResultUpdate();
+
+    await app.waitForFunction(
+      () =>
+        [...document.querySelectorAll('#console-container .luna-console-log-item')].some((item) =>
+          (item.textContent ?? '').includes('Hello from Scala'),
+        ),
+      undefined,
+      { timeout: 180_000 },
+    );
+  });
+
   test('Ruby', async ({ page, getTestUrl, editor }) => {
     test.skip(editor === 'codejar', 'please fix');
 

diff --git a/e2e/specs/starter.spec.ts b/e2e/specs/starter.spec.ts
@@ -351,6 +351,34 @@ test.describe('Starter Templates from UI', () => {
     await expect(getResult().locator('text=You clicked')).toHaveText('You clicked 3 times.');
   });
 
+  test('scala Starter', async ({ page, getTestUrl }) => {
+    // the compiler and the standard library are downloaded on the first run
+    test.slow();
+
+    await page.goto(getTestUrl());
+
+    const { app, getResult, waitForResultUpdate } = await getLoadedApp(page);
+
+    await app.click('[aria-label="Project"]');
+    await app.click('text=New');
+    await app.click('text=Scala Starter');
+
+    await waitForEditorFocus(app);
+    await waitForResultUpdate();
+
+    // the counter stays disabled until the runtime has loaded and run once
+    await expect(getResult().locator('#counter-button')).toBeEnabled({ timeout: 280_000 });
+
+    await getResult().click('text=Click me');
+    await getResult().click('text=Click me');
+    await getResult().click('text=Click me');
+
+    await expect(getResult().locator('h1')).toHaveText('Hello, Scala!');
+    // Each click triggers an asynchronous run, so the counter is asserted with
+    // retries rather than read once.
+    await expect(getResult().locator('text=You clicked')).toHaveText('You clicked 3 times.');
+  });
+
   test('swift-wasm Starter', async ({ page, getTestUrl }) => {
     // the Swift compiler, the linker and the stdlib sysroot (~70 MB) are downloaded on
     // the first run

diff --git a/functions/vendors/templates.js b/functions/vendors/templates.js
@@ -61,6 +61,7 @@ export const starterTemplates = {
   "d-wasm": "D Starter",
   "v-wasm": "V Starter",
   "rust-wasm": "Rust (Wasm) Starter",
+  "scala": "Scala Starter",
   "swift-wasm": "Swift (Wasm) Starter",
   "zig-wasm": "Zig (Wasm) Starter",
   "java": "Java Starter",

diff --git a/scripts/build.js b/scripts/build.js
@@ -229,6 +229,7 @@ const iifeBuild = () =>
       'languages/commonlisp/lang-commonlisp-script.ts',
       'languages/java-8/lang-java-8-script.ts',
       'languages/java-wasm/lang-java-wasm-script.ts',
+      'languages/scala-wasm/lang-scala-wasm-script.ts',
       'languages/cpp/lang-cpp-script.ts',
       'languages/clang-wasm/lang-clang-wasm-script.ts',
       'languages/nim/lang-nim-wasm-script.ts',

diff --git a/server/php/inc/starter-templates.json b/server/php/inc/starter-templates.json
@@ -61,6 +61,7 @@
   "d-wasm": "D Starter",
   "v-wasm": "V Starter",
   "rust-wasm": "Rust (Wasm) Starter",
+  "scala": "Scala Starter",
   "swift-wasm": "Swift (Wasm) Starter",
   "zig-wasm": "Zig (Wasm) Starter",
   "java": "Java Starter",

diff --git a/src/livecodes/UI/command-menu-actions.ts b/src/livecodes/UI/command-menu-actions.ts
@@ -317,6 +317,7 @@ export const getCommandMenuActions = ({
         'odin-wasm',
         'v-wasm',
         'rust-wasm',
+        'scala',
         'swift-wasm',
         'zig-wasm',
         'java',

diff --git a/src/livecodes/assets/templates/scala.svg b/src/livecodes/assets/templates/scala.svg
diff --git a/src/livecodes/html/language-info.html b/src/livecodes/html/language-info.html
@@ -2647,6 +2647,38 @@ <h3 data-i18n="language-info:sass.name">Sass</h3>
     </li>
   </ul>
 </section>
+<section data-lang="scala-wasm">
+  <h3 data-i18n="language-info:scalaWasm.name">Scala (Wasm)</h3>
+  <div data-i18n="language-info:scalaWasm.desc" data-i18n-prop="innerHTML">
+    Scala 3 is compiled and linked in the browser by the Scala 3 compiler and the Scala.js linker,
+    both running on WebAssembly. Nothing is sent to a server.
+  </div>
+  <ul data-i18n="language-info:scalaWasm.link" data-i18n-prop="innerHTML">
+    <li>
+      <a href="https://www.scala-lang.org/" target="_blank" rel="noopener"
+        >Scala official website</a
+      >
+    </li>
+    <li>
+      <a href="https://docs.scala-lang.org/" target="_blank" rel="noopener">Scala documentation</a>
+    </li>
+    <li>
+      <a href="https://www.scala-js.org/" target="_blank" rel="noopener"
+        >Scala.js official website</a
+      >
+    </li>
+    <li>
+      <a href="{{DOCS_BASE_URL}}languages/scala-wasm" target="_blank" rel="noopener"
+        >LiveCodes Documentation</a
+      >
+    </li>
+    <li>
+      <a href="?template=scala" class="button" target="_parent" data-template="scala"
+        >Load starter template</a
+      >
+    </li>
+  </ul>
+</section>
 <section data-lang="scheme">
   <h3 data-i18n="language-info:scheme.name">Scheme</h3>
   <div data-i18n="language-info:scheme.desc">Scheme running in the browser using biwascheme.</div>

diff --git a/src/livecodes/i18n/locales/ar/language-info.lokalise.json b/src/livecodes/i18n/locales/ar/language-info.lokalise.json
@@ -873,6 +873,15 @@
   "sass.name": {
     "translation": "Sass"
   },
+  "scalaWasm.desc": {
+    "translation": "يتم تجميع Scala 3 وربطه في المتصفح بواسطة مُترجم Scala 3 ورابط Scala.js، وكلاهما يعمل على WebAssembly. لا يُرسَل أي شيء إلى خادم."
+  },
+  "scalaWasm.link": {
+    "translation": "<tag-1> <tag-2>الموقع الرسمي لـ Scala</tag-2> </tag-1> <tag-3> <tag-4>وثائق Scala</tag-4> </tag-3> <tag-5> <tag-6>الموقع الرسمي لـ Scala.js</tag-6> </tag-5> <tag-7> <tag-8>وثائق LiveCodes</tag-8> </tag-7> <tag-9> <tag-10>تحميل قالب البدء</tag-10> </tag-9>"
+  },
+  "scalaWasm.name": {
+    "translation": "Scala (Wasm)"
+  },
   "scheme.desc": {
     "translation": "Scheme تعمل في المتصفح باستخدام biwascheme."
   },

diff --git a/src/livecodes/i18n/locales/ar/language-info.ts b/src/livecodes/i18n/locales/ar/language-info.ts
@@ -488,6 +488,11 @@ const languageInfo: I18nLangInfoTranslation = {
     link: '<1> <2>الموقع الرسمي لـ Sass</2> </1> <3> <4>وثائق Sass</4> </3> <5> <6>بناء جملة Sass (المسافة البادئة)</6> </5> <7> <8>تعلم X في Y دقيقة، حيث X=sass</8> </7>',
     name: 'Sass',
   },
+  scalaWasm: {
+    desc: 'يتم تجميع Scala 3 وربطه في المتصفح بواسطة مُترجم Scala 3 ورابط Scala.js، وكلاهما يعمل على WebAssembly. لا يُرسَل أي شيء إلى خادم.',
+    link: '<1> <2>الموقع الرسمي لـ Scala</2> </1> <3> <4>وثائق Scala</4> </3> <5> <6>الموقع الرسمي لـ Scala.js</6> </5> <7> <8>وثائق LiveCodes</8> </7> <9> <10>تحميل قالب البدء</10> </9>',
+    name: 'Scala (Wasm)',
+  },
   scheme: {
     desc: 'Scheme تعمل في المتصفح باستخدام biwascheme.',
     link: '<1> <2>لغة البرمجة Scheme</2> </1> <3> <4>الموقع الرسمي لـ BiwaScheme</4> </3> <5> <6>مرجع BiwaScheme</6> </5> <7> <8>تحميل قالب البداية</8> </7>',

diff --git a/src/livecodes/i18n/locales/ar/translation.lokalise.json b/src/livecodes/i18n/locales/ar/translation.lokalise.json
@@ -2160,6 +2160,9 @@
   "templates.starter.rust-wasm": {
     "translation": "قالب Rust (Wasm)"
   },
+  "templates.starter.scala": {
+    "translation": "قالب Scala"
+  },
   "templates.starter.scheme": {
     "translation": "قالب Scheme"
   },

diff --git a/src/livecodes/i18n/locales/ar/translation.ts b/src/livecodes/i18n/locales/ar/translation.ts
@@ -1059,6 +1059,7 @@ const translation: I18nTranslation = {
       ruby: 'قالب Ruby',
       'ruby-wasm': 'قالب Ruby-Wasm',
       'rust-wasm': 'قالب Rust (Wasm)',
+      scala: 'قالب Scala',
       scheme: 'قالب Scheme',
       shadcnui: 'قالب shadcn/ui',
       solid: 'قالب Solid',

diff --git a/src/livecodes/i18n/locales/bn/language-info.lokalise.json b/src/livecodes/i18n/locales/bn/language-info.lokalise.json
@@ -873,6 +873,15 @@
   "sass.name": {
     "translation": "Sass"
   },
+  "scalaWasm.desc": {
+    "translation": "Scala 3 ব্রাউজারে Scala 3 কম্পাইলার এবং Scala.js লিঙ্কার দ্বারা কম্পাইল ও লিঙ্ক করা হয়, উভয়ই WebAssembly-তে চলে। কোনো সার্ভারে কিছু পাঠানো হয় না।"
+  },
+  "scalaWasm.link": {
+    "translation": "<tag-1> <tag-2>Scala অফিসিয়াল ওয়েবসাইট</tag-2> </tag-1> <tag-3> <tag-4>Scala ডকুমেন্টেশন</tag-4> </tag-3> <tag-5> <tag-6>Scala.js অফিসিয়াল ওয়েবসাইট</tag-6> </tag-5> <tag-7> <tag-8>লাইভকোড ডকুমেন্টেশন</tag-8> </tag-7> <tag-9> <tag-10>স্টার্টার টেমপ্লেট লোড করুন</tag-10> </tag-9>"
+  },
+  "scalaWasm.name": {
+    "translation": "Scala (Wasm)"
+  },
   "scheme.desc": {
     "translation": "biwascheme ব্যবহার করে ব্রাউজারে চলমান Scheme।"
   },