[🐛 Bug]: [java] [BiDi] [grid] Impossible to load Chrome extension

[Zlaman]

Description

It is impossible to load Chrome extension in a new BiDi way on Selenium Grid, while same code perfectly works locally without Grid.

Pre-conditions:

1. Download a Chrome extension as zip file and unpack.
   You can use below zip file or download it yourself from https://chromewebstore.google.com/detail/modheader-modify-http-hea/idgpnmonknjnojddfkpgkljpfnnfcklj?utm_source=ext_app_menu with https://chromewebstore.google.com/detail/crx-extractordownloader/ajkhmmldknmfjnmeedkbkkojgobmljda extension.
   ModHeader-Modify-HTTP-headers-Chrome-Web-Store.zip
2. Selenium Grid started
   I used docker run -d --rm -p 4444:4444 -p 7900:7900 --shm-size="2g" --name chrome -e SE_NODE_GRID_URL=http://localhost:4444 selenium/standalone-chrome command.

Below code is running Chrome locally and works perfectly:

        ChromeOptions chromeOptions = new ChromeOptions();
        chromeOptions.addArguments("--enable-unsafe-extension-debugging");
        chromeOptions.addArguments("--remote-debugging-pipe");
        chromeOptions.enableBiDi();
        WebDriver driver = new ChromeDriver(chromeOptions);
        new WebExtension(driver).install(new InstallExtensionParameters(new ExtensionPath("C:\\Users\\zalma\\Desktop\\ModHeader-Modify-HTTP-headers-Chrome-Web-Store")));
        driver.navigate().to("https://google.com");

Now run Reproducible Code section for the same in Selenium Grid
It will fail with below logs and exception

Oct 29, 2025 10:18:19 PM org.openqa.selenium.remote.tracing.opentelemetry.OpenTelemetryTracer createTracer
INFO: Using OpenTelemetry for tracing
Oct 29, 2025 10:18:21 PM org.openqa.selenium.devtools.DevToolsProvider getImplementation
INFO: WebDriver augmented with DevTools interface; connection will not be verified until first use.
Oct 29, 2025 10:18:21 PM org.openqa.selenium.bidi.BiDiProvider getImplementation
INFO: WebDriver augmented with BiDi interface; connection will not be verified until first use.

org.openqa.selenium.bidi.BiDiException: {"error":"unknown error","id":1,"message":"Manifest file is missing or unreadable","stacktrace":"Error\n    at new UnknownErrorException (\u003Canonymous>:65:5590)\n    at CommandProcessor.processCommand (\u003Canonymous>:485:13142)","type":"error"}
Build info: version: '4.38.0', revision: '6b412e825c*'
System info: os.name: 'Windows 10', os.arch: 'amd64', os.version: '10.0', java.version: '21.0.2'
Driver info: driver.version: unknown

	at org.openqa.selenium.bidi.Connection.sendAndWait(Connection.java:178)
	at org.openqa.selenium.bidi.BiDi.send(BiDi.java:51)
	at org.openqa.selenium.bidi.webextension.WebExtension.install(WebExtension.java:42)
	at selenium.SeleniumExtensionTest.extTest(SeleniumExtensionTest.java:37)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at org.testng.internal.invokers.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:139)
	at org.testng.internal.invokers.TestInvoker.invokeMethod(TestInvoker.java:664)
	at org.testng.internal.invokers.TestInvoker.invokeTestMethod(TestInvoker.java:227)
	at org.testng.internal.invokers.MethodRunner.runInSequence(MethodRunner.java:50)
	at org.testng.internal.invokers.TestInvoker$MethodInvocationAgent.invoke(TestInvoker.java:957)
	at org.testng.internal.invokers.TestInvoker.invokeTestMethods(TestInvoker.java:200)
	at org.testng.internal.invokers.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:148)
	at org.testng.internal.invokers.TestMethodWorker.run(TestMethodWorker.java:128)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
	at org.testng.TestRunner.privateRun(TestRunner.java:848)
	at org.testng.TestRunner.run(TestRunner.java:621)
	at org.testng.SuiteRunner.runTest(SuiteRunner.java:443)
	at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:437)
	at org.testng.SuiteRunner.privateRun(SuiteRunner.java:397)
	at org.testng.SuiteRunner.run(SuiteRunner.java:336)
	at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
	at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:95)
	at org.testng.TestNG.runSuitesSequentially(TestNG.java:1280)
	at org.testng.TestNG.runSuitesLocally(TestNG.java:1200)
	at org.testng.TestNG.runSuites(TestNG.java:1114)
	at org.testng.TestNG.run(TestNG.java:1082)
	at com.intellij.rt.testng.IDEARemoteTestNG.run(IDEARemoteTestNG.java:65)
	at com.intellij.rt.testng.RemoteTestNGStarter.main(RemoteTestNGStarter.java:105)
Caused by: org.openqa.selenium.WebDriverException: {"error":"unknown error","id":1,"message":"Manifest file is missing or unreadable","stacktrace":"Error\n    at new UnknownErrorException (\u003Canonymous>:65:5590)\n    at CommandProcessor.processCommand (\u003Canonymous>:485:13142)","type":"error"}
Build info: version: '4.38.0', revision: '6b412e825c*'
System info: os.name: 'Windows 10', os.arch: 'amd64', os.version: '10.0', java.version: '21.0.2'
Driver info: driver.version: unknown
	at org.openqa.selenium.bidi.Connection.handleResponse(Connection.java:327)
	at org.openqa.selenium.bidi.Connection.handle(Connection.java:302)
	at org.openqa.selenium.bidi.Connection$Listener.lambda$onText$0(Connection.java:277)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
	at java.base/java.lang.Thread.run(Thread.java:1583)

Reproducible Code

        ChromeOptions chromeOptions = new ChromeOptions();
        chromeOptions.addArguments("--enable-unsafe-extension-debugging");
        chromeOptions.addArguments("--remote-debugging-pipe");
        chromeOptions.enableBiDi();
        WebDriver driver = new RemoteWebDriver(getSeleniumServerUrl(), chromeOptions);
        WebDriver augmented = new Augmenter().augment(driver);
        new WebExtension(augmented).install(new InstallExtensionParameters(new ExtensionPath("C:\\Users\\zalma\\Desktop\\ModHeader-Modify-HTTP-headers-Chrome-Web-Store")));
        driver.navigate().to("https://google.com");

    private static URL getSeleniumServerUrl() {
        try {
            return URI.create("http://172.17.101.161:4444/wd/hub").toURL();
        } catch (MalformedURLException e) {
            throw new RuntimeException("Selenium grid hub URL is invalid", e);
        }
    }

Debugging Logs

Oct 29, 2025 10:20:54 PM org.openqa.selenium.remote.tracing.opentelemetry.OpenTelemetryTracer createTracer
INFO: Using OpenTelemetry for tracing
Oct 29, 2025 10:20:55 PM org.openqa.selenium.remote.RemoteWebDriver log
FINE: Executing: newSession [null, newSession {capabilities=[Capabilities {browserName: chrome, goog:chromeOptions: {args: [--enable-unsafe-extension-d..., --remote-debugging-pipe], extensions: []}, webSocketUrl: true}]}]
Oct 29, 2025 10:20:55 PM org.openqa.selenium.remote.http.jdk.JdkHttpClient execute0
FINE: Executing request: (POST) /session
Oct 29, 2025 10:20:56 PM org.openqa.selenium.remote.http.jdk.JdkHttpClient execute0
FINE: Ending request (POST) /session in 727ms
Oct 29, 2025 10:20:56 PM io.opentelemetry.sdk.trace.SdkSpan setStatus
FINE: Ignoring setStatus() description since status is not ERROR.
Oct 29, 2025 10:20:56 PM org.openqa.selenium.remote.tracing.opentelemetry.SeleniumSpanExporter$1 lambda$export$4
FINE: SpanData{spanContext=ImmutableSpanContext{traceId=f75e5cb4e29f2c3fbda932747d215ca6, spanId=c424753805287815, traceFlags=01, traceState=ArrayBasedTraceState{entries=[]}, remote=false, valid=true}, parentSpanContext=ImmutableSpanContext{traceId=f75e5cb4e29f2c3fbda932747d215ca6, spanId=a0a8f080e5c8c711, traceFlags=01, traceState=ArrayBasedTraceState{entries=[]}, remote=false, valid=true}, resource=Resource{schemaUrl=null, attributes={service.name="unknown_service:java", telemetry.sdk.language="java", telemetry.sdk.name="opentelemetry", telemetry.sdk.version="1.55.0"}}, instrumentationScopeInfo=InstrumentationScopeInfo{name=default, version=null, schemaUrl=null, attributes={}}, name=httpclient.execute, kind=INTERNAL, startEpochNanos=1761801655542322500, endEpochNanos=1761801656280847099, attributes=AttributesMap{data={http.status_code=200, span.kind=client, http.target=/session, http.method=POST}, capacity=128, totalAddedValues=4}, totalAttributeCount=4, events=[], totalRecordedEvents=0, links=[], totalRecordedLinks=0, status=ImmutableStatusData{statusCode=OK, description=}, hasEnded=true}
Oct 29, 2025 10:20:56 PM org.openqa.selenium.remote.ProtocolHandshake createSession
FINE: Detected upstream dialect: W3C
Oct 29, 2025 10:20:56 PM org.openqa.selenium.remote.tracing.opentelemetry.SeleniumSpanExporter$1 lambda$export$4
FINE: SpanData{spanContext=ImmutableSpanContext{traceId=f75e5cb4e29f2c3fbda932747d215ca6, spanId=a0a8f080e5c8c711, traceFlags=01, traceState=ArrayBasedTraceState{entries=[]}, remote=false, valid=true}, parentSpanContext=ImmutableSpanContext{traceId=00000000000000000000000000000000, spanId=0000000000000000, traceFlags=00, traceState=ArrayBasedTraceState{entries=[]}, remote=false, valid=false}, resource=Resource{schemaUrl=null, attributes={service.name="unknown_service:java", telemetry.sdk.language="java", telemetry.sdk.name="opentelemetry", telemetry.sdk.version="1.55.0"}}, instrumentationScopeInfo=InstrumentationScopeInfo{name=default, version=null, schemaUrl=null, attributes={}}, name=newSession, kind=INTERNAL, startEpochNanos=1761801655448508700, endEpochNanos=1761801656315779700, attributes=AttributesMap{data={command=newSession, parameter.capabilities=[Capabilities {browserName: chrome, goog:chromeOptions: {args: [--enable-unsafe-extension-d..., --remote-debugging-pipe], extensions: []}, webSocketUrl: true}]}, capacity=128, totalAddedValues=2}, totalAttributeCount=2, events=[], totalRecordedEvents=0, links=[], totalRecordedLinks=0, status=ImmutableStatusData{statusCode=UNSET, description=}, hasEnded=true}
Oct 29, 2025 10:20:56 PM org.openqa.selenium.remote.RemoteWebDriver log
FINE: Executed: newSession Capabilities {acceptInsecureCerts: false, browserName: chrome, browserVersion: 142.0.7444.59, chrome: {chromedriverVersion: 142.0.7444.59 (4b8153ab58d3..., userDataDir: /tmp/.org.chromium.Chromium...}, fedcm:accounts: true, goog:chromeOptions: {args: [--enable-unsafe-extension-d..., --remote-debugging-pipe], extensions: []}, goog:processID: 887, networkConnectionEnabled: false, pageLoadStrategy: normal, platformName: linux, proxy: Proxy(), se:cdp: ws://localhost:4444/session..., se:containerName: c44fd055244e, se:deleteSessionOnUi: true, se:downloadsEnabled: true, se:gridWebSocketUrl: ws://localhost:9260/session..., se:noVncPort: 7900, se:vnc: ws://localhost:4444/session..., se:vncEnabled: true, se:vncLocalAddress: ws://172.18.0.2:7900, setWindowRect: true, strictFileInteractability: false, timeouts: {implicit: 0, pageLoad: 300000, script: 30000}, unhandledPromptBehavior: dismiss and notify, webSocketUrl: ws://localhost:4444/session..., webauthn:extension:credBlob: true, webauthn:extension:largeBlob: true, webauthn:extension:minPinLength: true, webauthn:extension:prf: true, webauthn:virtualAuthenticators: true}
Oct 29, 2025 10:20:56 PM org.openqa.selenium.bidi.BiDiProvider getImplementation
INFO: WebDriver augmented with BiDi interface; connection will not be verified until first use.
Oct 29, 2025 10:20:56 PM org.openqa.selenium.devtools.DevToolsProvider getImplementation
INFO: WebDriver augmented with DevTools interface; connection will not be verified until first use.
Oct 29, 2025 10:20:56 PM org.openqa.selenium.bidi.Connection send
FINE: -> {
  "method": "webExtension.install",
  "id": 1,
  "params": {
    "extensionData": {
      "path": "C:\\Users\\zalma\\Desktop\\ModHeader-Modify-HTTP-headers-Chrome-Web-Store",
      "type": "path"
    }
  }
}
Oct 29, 2025 10:20:56 PM org.openqa.selenium.remote.http.jdk.JdkHttpClient$4 send
FINE: Sending text message: {
  "method": "webExtension.install",
  "id": 1,
  "params": {
    "extensionData": {
      "path": "C:\\Users\\zalma\\Desktop\\ModHeader-Modify-HTTP-headers-Chrome-Web-Store",
      "type": "path"
    }
  }
}
Oct 29, 2025 10:20:56 PM org.openqa.selenium.remote.http.jdk.JdkHttpClient$4 send
FINE: Websocket response to org.openqa.selenium.remote.http.TextMessage@54f66455 read in 0ms
Oct 29, 2025 10:20:56 PM org.openqa.selenium.remote.http.jdk.JdkHttpClient$3 onText
FINE: Text message received. Appending data
Oct 29, 2025 10:20:56 PM org.openqa.selenium.remote.http.jdk.JdkHttpClient$3 onText
FINE: Final part of text message received. Calling listener with {"error":"unknown error","id":1,"message":"Manifest file is missing or unreadable","stacktrace":"Error\n    at new UnknownErrorException (\u003Canonymous>:65:5590)\n    at CommandProcessor.processCommand (\u003Canonymous>:485:13142)","type":"error"}
Oct 29, 2025 10:20:56 PM org.openqa.selenium.bidi.Connection handle
FINE: <- {"error":"unknown error","id":1,"message":"Manifest file is missing or unreadable","stacktrace":"Error\n    at new UnknownErrorException (\u003Canonymous>:65:5590)\n    at CommandProcessor.processCommand (\u003Canonymous>:485:13142)","type":"error"}

org.openqa.selenium.bidi.BiDiException: {"error":"unknown error","id":1,"message":"Manifest file is missing or unreadable","stacktrace":"Error\n    at new UnknownErrorException (\u003Canonymous>:65:5590)\n    at CommandProcessor.processCommand (\u003Canonymous>:485:13142)","type":"error"}
Build info: version: '4.38.0', revision: '6b412e825c*'
System info: os.name: 'Windows 10', os.arch: 'amd64', os.version: '10.0', java.version: '21.0.2'
Driver info: driver.version: unknown

	at org.openqa.selenium.bidi.Connection.sendAndWait(Connection.java:178)
	at org.openqa.selenium.bidi.BiDi.send(BiDi.java:51)
	at org.openqa.selenium.bidi.webextension.WebExtension.install(WebExtension.java:42)
	at selenium.SeleniumExtensionTest.extTest(SeleniumExtensionTest.java:37)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at org.testng.internal.invokers.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:139)
	at org.testng.internal.invokers.TestInvoker.invokeMethod(TestInvoker.java:664)
	at org.testng.internal.invokers.TestInvoker.invokeTestMethod(TestInvoker.java:227)
	at org.testng.internal.invokers.MethodRunner.runInSequence(MethodRunner.java:50)
	at org.testng.internal.invokers.TestInvoker$MethodInvocationAgent.invoke(TestInvoker.java:957)
	at org.testng.internal.invokers.TestInvoker.invokeTestMethods(TestInvoker.java:200)
	at org.testng.internal.invokers.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:148)
	at org.testng.internal.invokers.TestMethodWorker.run(TestMethodWorker.java:128)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
	at org.testng.TestRunner.privateRun(TestRunner.java:848)
	at org.testng.TestRunner.run(TestRunner.java:621)
	at org.testng.SuiteRunner.runTest(SuiteRunner.java:443)
	at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:437)
	at org.testng.SuiteRunner.privateRun(SuiteRunner.java:397)
	at org.testng.SuiteRunner.run(SuiteRunner.java:336)
	at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
	at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:95)
	at org.testng.TestNG.runSuitesSequentially(TestNG.java:1280)
	at org.testng.TestNG.runSuitesLocally(TestNG.java:1200)
	at org.testng.TestNG.runSuites(TestNG.java:1114)
	at org.testng.TestNG.run(TestNG.java:1082)
	at com.intellij.rt.testng.IDEARemoteTestNG.run(IDEARemoteTestNG.java:65)
	at com.intellij.rt.testng.RemoteTestNGStarter.main(RemoteTestNGStarter.java:105)
Caused by: org.openqa.selenium.WebDriverException: {"error":"unknown error","id":1,"message":"Manifest file is missing or unreadable","stacktrace":"Error\n    at new UnknownErrorException (\u003Canonymous>:65:5590)\n    at CommandProcessor.processCommand (\u003Canonymous>:485:13142)","type":"error"}
Build info: version: '4.38.0', revision: '6b412e825c*'
System info: os.name: 'Windows 10', os.arch: 'amd64', os.version: '10.0', java.version: '21.0.2'
Driver info: driver.version: unknown
	at org.openqa.selenium.bidi.Connection.handleResponse(Connection.java:327)
	at org.openqa.selenium.bidi.Connection.handle(Connection.java:302)
	at org.openqa.selenium.bidi.Connection$Listener.lambda$onText$0(Connection.java:277)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
	at java.base/java.lang.Thread.run(Thread.java:1583)

[selenium-ci]

@Zlaman, thank you for creating this issue. We will troubleshoot it as soon as we can.

Selenium Triage Team: remember to follow the Triage Guide

[cgoldberg]

FWIW, I can load your extension fine using Remote WebDriver in Python.

[Zlaman]

FWIW, I can load your extension fine using Remote WebDriver in Python.

Do you use Chrome 142 in the Grid and WebExtension feature to install extension?

[cgoldberg]

Do you use Chrome 142 in the Grid and WebExtension feature to install extension?

yes, selenium server 4.38, Chrome 142, and BiDi webextension.install()

[cgoldberg]

I just noticed you are running your Grid server in a docker container without any mounts/volumes mapped.

Your log shows:

"method": "webExtension.install",
  "id": 1,
  "params": {
    "extensionData": {
      "path": "C:\\Users\\zalma\\Desktop\\ModHeader-Modify-HTTP-headers-Chrome-Web-Store",
      "type": "path"
    }
  }

It is only sending the path to the extension, which the driver/browser will not have access to since it can't see the host filesystem. In my case, I was running the server locally, so it could access the path I sent.

I don't know how the Java bindings handle this, so someone else would have to help... but in Python, if you want actually send the extension over the wire (instead of just its path), you have to base64 encode the archived extension and call webextension.install(base64_value=BASE64_VALUE) with the encoded data.

[Zlaman]

Yes I do not have any mounts. Grid can be running somewhere remotely and I supposed it will transfer the extension over the network.
There are ExtensionBase64Encoded and ExtensionArchivePath types to pass to InstallExtensionParameters in Java bindings, but they are not supported - I am getting org.openqa.selenium.bidi.BiDiException: {"error":"unsupported operation","id":1,"message":"Archived and Base64 extensions are not supported","type":"error"}

[cgoldberg]

Chrome must not support that yet... in CI, we are only testing base64 encoded extension installation with Firefox.

selenium/py/test/selenium/webdriver/common/bidi_webextension_tests.py

Line 85 in 9b24abb

def test_install_base64_extension_path(self, driver, pages):

[SKumar-777]

Hi Team,

Switching to Chromium or Chrome-for-Testing is not allowed in our production environments.

The following Selenium (v4.38) C# code using Remote Web Driver does not work for me:

var options = new ChromeOptions();
//options.AddArgument("--disable-features=DisableLoadExtensionCommandLineSwitch"); // Does not fix this issue.
options.UseWebSocketUrl = true; // Does not fix this issue.
options.AddArgument("--load-extension=" + extensionPath); // Load unpacked extension
options.AddArgument("--remote-debugging-pipe");
options.AddArgument("--enable-unsafe-extension-debugging");

var driver = new ChromeDriver(options);
driver = new RemoteWebDriver(new Uri("http://localhost:xxxx"), options);

Will the Selenium team be addressing this issue?

[cgoldberg]

Will the Selenium team be addressing this issue?

No.. it is a restriction in Chrome. Use BiDi or switch to Chromium. see #15788