diff --git a/package.json b/package.json
index f5210bf..8cec88c 100644
--- a/package.json
+++ b/package.json
@@ -970,8 +970,9 @@
         "prewatch-web": "node ./scripts/build-local-model-library.js",
         "compile-web": "webpack",
         "watch-web": "webpack --watch",
-        "test": "npm run test:fuzzy && npm run test:image-decoders && npm run test:diagnostics && npm run test:language-features && npm run test:editor-work && npm run test:webview && npm run test:private-libraries",
+        "test": "npm run test:appcds && npm run test:fuzzy && npm run test:image-decoders && npm run test:diagnostics && npm run test:language-features && npm run test:editor-work && npm run test:webview && npm run test:private-libraries",
         "test:private-libraries": "node ./scripts/test-private-library-loader.js",
+        "test:appcds": "node ./scripts/test-appcds.js",
         "test:e2e:production": "npm run package-web && playwright test --project=webview",
         "test:editor-work": "node ./scripts/test-editor-work.js",
         "test:e2e": "npm run compile-web && playwright test --project=webview",
diff --git a/scripts/test-appcds.js b/scripts/test-appcds.js
new file mode 100644
index 0000000..86deb6d
--- /dev/null
+++ b/scripts/test-appcds.js
@@ -0,0 +1,75 @@
+'use strict';
+
+const assert = require('assert');
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
+const { createTsLoader } = require('../e2e/harness/tsLoader');
+
+const { appCdsJvmOptions } = createTsLoader()('src/install/fsUtils.ts');
+
+function install(root, release = 'JAVA_VERSION="25.0.1"\n') {
+    const runtime = path.join(root, 'wurst-runtime');
+    const compiler = path.join(root, 'wurst-compiler');
+    fs.mkdirSync(path.join(runtime, 'bin'), { recursive: true });
+    fs.mkdirSync(compiler, { recursive: true });
+    fs.writeFileSync(path.join(runtime, 'release'), release);
+    const java = path.join(runtime, 'bin', 'java.exe');
+    const jar = path.join(compiler, 'wurstscript.jar');
+    fs.writeFileSync(java, '');
+    fs.writeFileSync(jar, 'compiler 1');
+    return { java, jar, compiler };
+}
+
+function archiveOf(options) {
+    const flag = options.find((option) => option.startsWith('-XX:SharedArchiveFile='));
+    assert.ok(flag, `no archive in ${JSON.stringify(options)}`);
+    return flag.slice('-XX:SharedArchiveFile='.length);
+}
+
+const tmp = fs.mkdtempSync(path.join(os.tmpdir(), 'wurst-appcds-'));
+try {
+    const { java, jar, compiler } = install(tmp);
+
+    // the options: a JDK managed archive next to the jar, and no JVM log lines on the protocol stream
+    const options = appCdsJvmOptions(java, jar);
+    assert.deepStrictEqual(options.filter((option) => !option.startsWith('-XX:SharedArchiveFile=')),
+        ['-XX:+AutoCreateSharedArchive', '-Xlog:disable']);
+    const archive = archiveOf(options);
+    assert.strictEqual(path.dirname(archive), compiler);
+    assert.match(path.basename(archive), /^wurstscript-[0-9a-f]{12}\.jsa$/);
+    assert.deepStrictEqual(appCdsJvmOptions(java, jar), options, 'the same install gets the same archive');
+    assert.deepStrictEqual(fs.readdirSync(compiler), ['wurstscript.jar'], 'the write probe is removed');
+
+    // an update: the archive of the old jar does not fit and is not replaced by the JVM, so it is removed here
+    fs.writeFileSync(archive, 'archive of compiler 1');
+    fs.writeFileSync(path.join(compiler, 'notes.jsa'), 'not ours');
+    fs.writeFileSync(path.join(compiler, 'wurstscript-latest.jsa'), 'not ours');
+    fs.writeFileSync(jar, 'compiler 2 is longer');
+    const updated = archiveOf(appCdsJvmOptions(java, jar));
+    assert.notStrictEqual(updated, archive);
+    assert.ok(!fs.existsSync(archive), 'the archive of the old jar is removed');
+    assert.deepStrictEqual(fs.readdirSync(compiler).sort(), ['notes.jsa', 'wurstscript-latest.jsa', 'wurstscript.jar']);
+
+    // a jar with the same size, rewritten later, is another jar
+    const stat = fs.statSync(jar);
+    fs.utimesSync(jar, stat.atime, new Date(stat.mtimeMs + 5000));
+    assert.notStrictEqual(archiveOf(appCdsJvmOptions(java, jar)), updated);
+
+    // another runtime, at the same path or elsewhere, is another archive
+    const other = install(path.join(tmp, 'other'), 'JAVA_VERSION="25.0.3"\n');
+    fs.copyFileSync(jar, other.jar);
+    fs.utimesSync(other.jar, fs.statSync(jar).atime, fs.statSync(jar).mtime);
+    assert.notStrictEqual(archiveOf(appCdsJvmOptions(other.java, other.jar)).split(path.sep).pop(),
+        archiveOf(appCdsJvmOptions(java, jar)).split(path.sep).pop());
+
+    // a folder which cannot be written gets no options (the JVM aborts at exit when it cannot write the archive)
+    assert.deepStrictEqual(appCdsJvmOptions(java, path.join(tmp, 'missing', 'wurstscript.jar')), []);
+    // and so does a jar which is not there
+    fs.unlinkSync(jar);
+    assert.deepStrictEqual(appCdsJvmOptions(java, jar), []);
+    assert.ok(!fs.readdirSync(compiler).some((entry) => entry.startsWith('.write-probe')));
+    console.log('appcds options ok');
+} finally {
+    fs.rmSync(tmp, { recursive: true, force: true });
+}
diff --git a/scripts/test-lsp-appcds.js b/scripts/test-lsp-appcds.js
new file mode 100644
index 0000000..90a8ed4
--- /dev/null
+++ b/scripts/test-lsp-appcds.js
@@ -0,0 +1,108 @@
+'use strict';
+
+// Opt-in cross-repository test: pass the compiler jar of a built distribution and the java of its runtime
+// (the runtime needs the base CDS archive jlink makes): node scripts/test-lsp-appcds.js <compiler.jar> <java>
+const assert = require('assert');
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
+const { pathToFileURL } = require('url');
+const { spawn } = require('child_process');
+const { createProtocolConnection, StreamMessageReader, StreamMessageWriter } = require('vscode-languageserver-protocol/node');
+const { createTsLoader } = require('../e2e/harness/tsLoader');
+
+const { appCdsJvmOptions } = createTsLoader()('src/install/fsUtils.ts');
+
+async function session(java, jar, project, options) {
+    const child = spawn(java, [...options, '-jar', jar, '-languageServer'], { windowsHide: true, stdio: 'pipe' });
+    const connection = createProtocolConnection(new StreamMessageReader(child.stdout), new StreamMessageWriter(child.stdin));
+    let stderr = '';
+    child.stderr.on('data', (chunk) => { stderr = (stderr + chunk).slice(-4096); });
+    const closed = new Promise((resolve) => child.on('close', resolve));
+    const states = [];
+    let protocolErrors = 0;
+    let finished;
+    const ready = new Promise((resolve) => { finished = resolve; });
+    connection.onNotification('wurst/initialBuildStatus', (params) => {
+        states.push(params.state);
+        if (params.state === 'ready' || params.state === 'failed') finished();
+    });
+    connection.onRequest('window/workDoneProgress/create', () => null);
+    connection.onRequest('workspace/configuration', () => []);
+    connection.onRequest('client/registerCapability', () => null);
+    connection.onRequest('window/showMessageRequest', () => null);
+    connection.onNotification(() => {});
+    connection.onError(() => { protocolErrors++; });
+    connection.listen();
+    let timer;
+    const timeout = new Promise((_, reject) => { timer = setTimeout(() => reject(new Error(`no readiness: ${stderr}`)), 60000); });
+    const started = Date.now();
+    try {
+        await Promise.race([(async () => {
+            await connection.sendRequest('initialize', {
+                processId: process.pid, rootUri: pathToFileURL(project).toString(),
+                capabilities: { window: { workDoneProgress: false }, experimental: { wurstInitialBuildStatus: true } },
+            });
+            await connection.sendNotification('initialized', {});
+            await ready;
+        })(), timeout]);
+        const readyMs = Date.now() - started;
+        await connection.sendRequest('shutdown');
+        await connection.sendNotification('exit');
+        const code = await closed;
+        return { code, states, protocolErrors, readyMs };
+    } finally {
+        clearTimeout(timer);
+        child.kill();
+    }
+}
+
+async function main() {
+    const [jar, java] = process.argv.slice(2);
+    assert.ok(jar && java, 'usage: node scripts/test-lsp-appcds.js <compiler.jar> <java>');
+    const root = fs.mkdtempSync(path.join(os.tmpdir(), 'wurst-appcds-lsp-'));
+    try {
+        const project = path.join(root, 'project');
+        fs.mkdirSync(path.join(project, 'wurst'), { recursive: true });
+        fs.writeFileSync(path.join(project, 'wurst', 'Main.wurst'), 'package Main\nfunction beforeEdit()\n    skip\n');
+        // a copy, so that the archive is not written into the distribution which is being tested
+        const compilerDir = path.join(root, 'wurst-compiler');
+        fs.mkdirSync(compilerDir);
+        const copy = path.join(compilerDir, path.basename(jar));
+        fs.copyFileSync(jar, copy);
+
+        const options = appCdsJvmOptions(java, copy);
+        assert.ok(options.length > 0, 'the options are empty');
+        const archive = options.find((option) => option.startsWith('-XX:SharedArchiveFile=')).slice('-XX:SharedArchiveFile='.length);
+
+        const first = await session(java, copy, project, options);
+        assert.deepStrictEqual(first.states, ['loading', 'ready']);
+        assert.strictEqual(first.protocolErrors, 0);
+        assert.strictEqual(first.code, 0, 'the first session ends cleanly');
+        assert.ok(fs.existsSync(archive) && fs.statSync(archive).size > 0, 'the first session writes the archive');
+        const written = fs.statSync(archive).mtimeMs;
+
+        const second = await session(java, copy, project, options);
+        assert.deepStrictEqual(second.states, ['loading', 'ready']);
+        assert.strictEqual(second.protocolErrors, 0);
+        assert.strictEqual(second.code, 0);
+        assert.strictEqual(fs.statSync(archive).mtimeMs, written, 'the second session starts from the archive and leaves it');
+
+        // an update: the options name another archive, the old one goes, and the first session writes the new one
+        fs.appendFileSync(copy, '');
+        const stat = fs.statSync(copy);
+        fs.utimesSync(copy, stat.atime, new Date(stat.mtimeMs + 5000));
+        const updatedOptions = appCdsJvmOptions(java, copy);
+        assert.notDeepStrictEqual(updatedOptions, options);
+        assert.ok(!fs.existsSync(archive), 'the archive of the old jar is removed');
+        const third = await session(java, copy, project, updatedOptions);
+        assert.deepStrictEqual(third.states, ['loading', 'ready']);
+        assert.strictEqual(third.code, 0);
+        assert.ok(fs.existsSync(updatedOptions.find((option) => option.startsWith('-XX:SharedArchiveFile=')).slice('-XX:SharedArchiveFile='.length)));
+        console.log(`appcds language server ok (ready after ${first.readyMs} ms, then ${second.readyMs} ms)`);
+    } finally {
+        fs.rmSync(root, { recursive: true, force: true });
+    }
+}
+
+main().then(() => process.exit(0), (error) => { console.error(error); process.exit(1); });
diff --git a/src/install/fsUtils.ts b/src/install/fsUtils.ts
index 5b4da9b..cbf569c 100644
--- a/src/install/fsUtils.ts
+++ b/src/install/fsUtils.ts
@@ -1,11 +1,55 @@
 'use strict';
 
+import * as crypto from 'crypto';
 import * as fs from 'fs';
 import * as path from 'path';
 import {
     WURST_HOME, RUNTIME_DIR, COMPILER_DIR, GRILL_HOME_DIR, LEGACY_GRILL_DIR,
 } from '../paths';
 
+/**
+ * JVM options which start the language server from an AppCDS archive next to the compiler jar: the JVM writes the
+ * archive when the first session ends, and the sessions after it start from it (about 15% sooner).
+ *
+ * The archive is named after what it was recorded for (runtime, jar path, size and modification time). The JVM
+ * only ignores an archive which does not fit, it does not write a new one, so an update would leave the server
+ * without; the archives of other jars and runtimes are removed here instead. No options when the folder cannot
+ * be written, because the JVM then aborts when the session ends. `-Xlog:disable` because the JVM reports archive
+ * trouble on stdout, which is the protocol stream.
+ *
+ * Needs the runtime's own base archive, which the distribution builds (jlink --generate-cds-archive); without it
+ * the JVM runs as before.
+ */
+export function appCdsJvmOptions(javaExecutable: string, compilerJar: string): string[] {
+    try {
+        const dir = path.dirname(compilerJar);
+        // access(W_OK) says yes to any folder on Windows
+        const probe = path.join(dir, `.write-probe-${process.pid}`);
+        fs.writeFileSync(probe, '');
+        fs.unlinkSync(probe);
+
+        let release = '';
+        try {
+            release = fs.readFileSync(path.join(path.dirname(path.dirname(javaExecutable)), 'release'), 'utf8');
+        } catch {
+            // a java without a release file (from PATH) is told apart by its path
+        }
+        const jar = fs.statSync(compilerJar);
+        const key = crypto.createHash('sha1')
+            .update([javaExecutable, release, compilerJar, jar.size, Math.floor(jar.mtimeMs)].join('|'))
+            .digest('hex').slice(0, 12);
+        const archive = path.join(dir, `wurstscript-${key}.jsa`);
+        for (const entry of fs.readdirSync(dir)) {
+            if (/^wurstscript-[0-9a-f]{12}\.jsa$/.test(entry) && entry !== path.basename(archive)) {
+                try { fs.unlinkSync(path.join(dir, entry)); } catch { /* in use by a session of the old version */ }
+            }
+        }
+        return ['-XX:+AutoCreateSharedArchive', `-XX:SharedArchiveFile=${archive}`, '-Xlog:disable'];
+    } catch {
+        return [];
+    }
+}
+
 export function sleep(ms: number) {
     return new Promise((res) => setTimeout(res, ms));
 }
diff --git a/src/languageServer.ts b/src/languageServer.ts
index eb92862..704ce2d 100644
--- a/src/languageServer.ts
+++ b/src/languageServer.ts
@@ -5,6 +5,7 @@ import * as vscode from 'vscode';
 import { workspace, ExtensionContext } from 'vscode';
 import { LanguageClient, LanguageClientOptions, ServerOptions, Executable, State, DidOpenTextDocumentNotification } from 'vscode-languageclient/node';
 import { RUNTIME_DIR, COMPILER_JAR } from './paths';
+import { appCdsJvmOptions } from './install/fsUtils';
 import { getLanguageServerJava, checkCustomJavaVersion, getInstalledVersionString, ensureInstalledOrOfferMigration, maybeOfferUpdate } from './install/installer';
 import type { UpdateAvailable } from './install/installer';
 import { appendDiagnostic, formatDiagnosticError } from './features/diagnostics';
@@ -346,7 +347,7 @@ async function getServerOptions(): Promise<ServerOptions> {
     const java = getLanguageServerJava();
     if (customJava) await checkCustomJavaVersion(customJava);
     const platformOpts = process.platform === 'darwin' ? ['-Dapple.awt.UIElement=true'] : [];
-    const args = [...platformOpts, ...javaOpts, '-jar', COMPILER_JAR, '-languageServer'];
+    const args = [...platformOpts, ...appCdsJvmOptions(java, COMPILER_JAR), ...javaOpts, '-jar', COMPILER_JAR, '-languageServer'];
 
     if (debugMode && (await isPortOpen(5005))) {
         args.unshift('-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005,quiet=y');