diff --git a/build.gradle b/build.gradle
index c207759..5481565 100644
--- a/build.gradle
+++ b/build.gradle
@@ -20,6 +20,7 @@ dependencies {
     testCompile 'com.google.code.findbugs:jsr305:3.0.1'
     testCompile 'de.inetsoftware:jwebassembly-api:+'
     testCompile 'junit:junit:+'
+    testCompile 'org.apache.commons:commons-compress:1.2'
 }
 
 sourceSets {
diff --git a/test/de/inetsoftware/jwebassembly/Wat2Wasm.java b/test/de/inetsoftware/jwebassembly/Wat2Wasm.java
new file mode 100644
index 0000000..a6d8c71
--- /dev/null
+++ b/test/de/inetsoftware/jwebassembly/Wat2Wasm.java
@@ -0,0 +1,155 @@
+/*
+ * Copyright 2019 Volker Berlin (i-net software)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.inetsoftware.jwebassembly;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.StandardCopyOption;
+import java.time.Instant;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.zip.GZIPInputStream;
+
+import org.apache.commons.compress.archivers.ArchiveEntry;
+import org.apache.commons.compress.archivers.ArchiveInputStream;
+import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
+import org.apache.commons.compress.archivers.zip.ZipArchiveInputStream;
+import org.junit.Assert;
+
+/**
+ * Download the wat2wasm tool from github
+ * 
+ * @author Volker Berlin
+ */
+class Wat2Wasm {
+
+    private String command;
+
+    /**
+     * Check if there is a new version of the script engine
+     * 
+     * @throws IOException
+     *             if any error occur
+     */
+    private void download( File target ) throws IOException {
+        boolean is32 = "32".equals( System.getProperty( "sun.arch.data.model" ) );
+        String fileName;
+        final String os = System.getProperty( "os.name", "" ).toLowerCase();
+        if( os.contains( "windows" ) ) {
+            fileName = is32 ? "win32.zip" : "win64.zip";
+        } else if( os.contains( "mac" ) ) {
+            fileName = "osx.tar.gz";
+        } else if( os.contains( "linux" ) ) {
+            fileName = "linux.tar.gz";
+        } else {
+            throw new IllegalStateException( "Unknown OS: " + os );
+        }
+
+        HttpURLConnection conn = (HttpURLConnection)new URL( "https://api.github.com/repos/WebAssembly/wabt/releases/latest" ).openConnection();
+        InputStream input = conn.getInputStream();
+        String json = WasmRule.readStream( input );
+
+        Pattern pattern = Pattern.compile( "https://github.com/WebAssembly/wabt/releases/download/[0-9.]*/wabt-[0-9.]*-" + fileName );
+        Matcher matcher = pattern.matcher( json );
+        Assert.assertTrue( matcher.find() );
+        String downloadUrl = matcher.group();
+        System.out.println( "\tDownload: " + downloadUrl );
+
+        conn = (HttpURLConnection)new URL( downloadUrl ).openConnection();
+        if( target.exists() ) {
+            conn.setIfModifiedSince( target.lastModified() );
+        }
+
+        input = conn.getInputStream();
+        if( conn.getResponseCode() == HttpURLConnection.HTTP_NOT_MODIFIED ) {
+            System.out.println( "\tUP-TO-DATE, use version from " + Instant.ofEpochMilli( target.lastModified() ) );
+            return;
+        }
+
+        long lastModfied = conn.getLastModified();
+
+        ArchiveInputStream archiv;
+        if( fileName.endsWith( ".tar.gz" ) ) {
+            input = new GZIPInputStream( input );
+            archiv = new TarArchiveInputStream( input );
+        } else {
+            archiv = new ZipArchiveInputStream( input );
+        }
+
+        do {
+            ArchiveEntry entry = archiv.getNextEntry();
+            if( entry == null ) {
+                break;
+            }
+            if( entry.isDirectory() ) {
+                continue;
+            }
+            File file = new File( target, entry.getName() );
+            file.getParentFile().mkdirs();
+
+            Files.copy( archiv, file.toPath(), StandardCopyOption.REPLACE_EXISTING );
+            file.setLastModified( entry.getLastModifiedDate().getTime() );
+            file.setExecutable( true );
+        } while( true );
+
+        target.setLastModified( lastModfied );
+        System.out.println( "\tUse Version from " + Instant.ofEpochMilli( lastModfied ) );
+    }
+
+    /**
+     * Search the tool in the directory recursively and set the command.
+     * 
+     * @param dir
+     *            the directory
+     */
+    private void searchExecuteable( File dir ) {
+        File[] list = dir.listFiles();
+        if( list != null ) {
+            for( File file : list ) {
+                if( file.isDirectory() ) {
+                    searchExecuteable( file );
+                } else {
+                    if( file.getName().contains( "wat2wasm" ) ) {
+                        command = file.getAbsolutePath();
+                    }
+                }
+                if( command != null ) {
+                    return;
+                }
+            }
+        }
+    }
+
+    /**
+     * Get the executable command
+     * 
+     * @return the command
+     * @throws IOException
+     *             if any I/O error occur 
+     */
+    public String getCommand() throws IOException {
+        if( command == null ) {
+            File target = new File( System.getProperty( "java.io.tmpdir" ) + "/wabt" );
+            download( target );
+            searchExecuteable( target );
+        }
+        return command;
+    }
+}