Is there an existing issue for this?

• I have searched the existing issues

Appium Version

3.2.2

Appium Host Type

Command Line

Are you using Appium components not maintained by the Appium team?

No response

Is this issue reproducible using the latest components?

• I confirm the issue is still reproducible with the latest component versions

Current Behavior

The @wdio/appium-service has a "built-in" appium-inspector that can be started. This used to work with previous versions of Appium but it now fails. I've raised a PR for the service to remove the "complex" logic we have, see fix(appium-service): fix startup failure caused by Appium stderr log output
, but @eglitise suggested to also create an issue here.

Here's a sample of the logs that failed based on the current logic in the service

npx start-appium-inspector --port=4725 --relaxed-security

⏳ Checking inspector plugin...
🚀 Starting Appium server...
📡 Command: /Users/wimselles/Git/wdio/workshops/mobile-automation-appium-webdriverio-workshop/node_modules/appium/index.js server --port=4725 --relaxed-security --log-timestamp --use-plugins=inspector --allow-cors
⏳ Waiting for Appium server to be ready...
ℹ️  Press Ctrl+C to stop Appium server and exit


Error: dbug
    at Socket.onErrorMessage (file:///Users/wimselles/Git/wdio/workshops/mobile-automation-appium-webdriverio-workshop/node_modules/@wdio/appium-service/build/cli.js:141:22)
    at Socket.emit (node:events:508:28)
    at addChunk (node:internal/streams/readable:559:12)
    at readableAddChunkPushByteMode (node:internal/streams/readable:510:3)
    at Readable.push (node:internal/streams/readable:390:5)
    at Pipe.onStreamRead (node:internal/stream_base_commons:189:23)

Expected Behavior

it should be written to the stdout

Appium Log

No response

Environment Details

Minimal Reproducible Example

• start a simple wdio project with the service
• have older versions of Appium installed

{
  "name": "appium-inspector-stderror",
  "type": "module",
  "devDependencies": {
    "@types/node": "^25.5.0",
    "@wdio/appium-service": "^9.26.1",
    "@wdio/cli": "^9.26.1",
    "@wdio/globals": "^9.26.1",
    "@wdio/local-runner": "^9.26.1",
    "@wdio/mocha-framework": "^9.26.1",
    "@wdio/spec-reporter": "^9.26.1",
    "appium": "3.1.1",
    "appium-inspector-plugin": "^2026.2.1",
    "appium-uiautomator2-driver": "^7.0.0",
    "expect-webdriverio": "^5.6.5"
  }
}

• run npx start-appium-inspector => it works
• upgrade the appium versions

{
  "name": "appium-inspector-stderror",
  "type": "module",
  "devDependencies": {
    "@types/node": "^25.5.0",
    "@wdio/appium-service": "^9.26.1",
    "@wdio/cli": "^9.26.1",
    "@wdio/globals": "^9.26.1",
    "@wdio/local-runner": "^9.26.1",
    "@wdio/mocha-framework": "^9.26.1",
    "@wdio/spec-reporter": "^9.26.1",
    "appium": "3.2.2",
    "appium-inspector-plugin": "^2026.2.1",
    "appium-uiautomator2-driver": "^7.0.0",
    "expect-webdriverio": "^5.6.5"
  }
}

• run npx start-appium-inspector => it fails

Further Information

No response