Performance Monitoring troubleshooting and FAQ

How to view log messages for performance events

1. Open your browser's developer tools (for example, Network tab for Chrome Dev Tools or in the Network Monitor for Firefox).

2. Refresh your web app in the browser.

3. Check your log messages for any error messages.

4. After a few seconds, look for a network call to firebaselogging.googleapis.com in your browser's developer tools. The presence of that network call shows that the browser is sending performance data to Firebase.

If your app isn't logging performance events, review the troubleshooting tips.

Added the SDK to app, but console still says to add SDK

Firebase can detect if you've successfully added the Performance Monitoring SDK to your app when it receives event information (like app interactions) from your app. Usually within 10 minutes of starting your app, the Performance dashboard of the Firebase console displays an "SDK detected" message. Then, within 30 minutes, the dashboard displays the initial processed data.

If it's been more than 10 minutes since you added the latest version of SDK to your app, and you're still not seeing any change, check your log messages to make sure that Performance Monitoring is logging events. Try the appropriate troubleshooting steps as described below to troubleshoot a delayed SDK detection message.

Console says the SDK is detected, but no data is displayed

Performance Monitoring processes performance event data before displaying it in the Performance dashboard.

If it's been more than 24 hours since the "SDK detected" message appeared, and you're still not seeing data, then check the Firebase Status Dashboard in case there is a known outage. If there is no outage, contact Firebase Support.

App is not logging performance events

If you're not seeing log messages for performance events, try the following troubleshooting steps:

1. Make sure that the Performance Monitoring SDK is correctly initialized in your app.

2. Make sure that the Performance Monitoring SDK is not disabled through the following flag:

   • performance.instrumentationEnabled

3. Make sure that your browser caching is disabled, otherwise the browser might not pick up any new instrumentation settings.

4. Close, then reopen the webpage tab. Check for logging again.

   If you just added the Performance Monitoring SDK in your app, you might need to fully restart your app for the SDK to start working.

5. If you can't find anything that's disabled in your app, contact Firebase Support.

Performance dashboard is missing first input delay data

If you're not seeing data for the first input delay metric, try the following troubleshooting steps:

1. Be aware that Performance Monitoring only records the first input delay metric when a user clicks on the web page within the first 5 seconds after page load.

2. Make sure that you've set up your app to measure this metric. The first input delay metric requires manual setup. Specifically, you need to add the polyfill library for this metric. For installation instructions, refer to the library's documentation.

   Note that adding this polyfill library is not required for Performance Monitoring to report other web app metrics.

Performance dashboard is missing custom trace data

Are you seeing performance data for automatically collected traces but not for custom code traces? Try the following troubleshooting steps:

1. Check the setup of custom code traces instrumented via the Trace API, especially the following:

   • Names for custom code traces and custom metrics must meet the following requirements: no leading or trailing whitespace, no leading underscore (_) character, and max length is 32 characters.
   • All traces must be started and stopped. Any trace that is not started, not stopped, or stopped before started will not be logged.

   Note that if you're using the record() method, then you don't need to explicitly start or stop your trace.

2. Make sure that Performance Monitoring data collection is not disabled through the following flag:

   • performance.dataCollectionEnabled

     This flag controls the collection of data for custom code traces only (not all data).

3. Check your log messages to make sure that Performance Monitoring is logging expected custom code traces.

4. If Performance Monitoring is logging events, but no data displays after 24 hours, contact Firebase Support.

Performance dashboard is missing network request data

If you're missing network request data, be aware of the following:

• Performance Monitoring automatically collects metrics for network requests reported by the browser API. These reports do not include failed network requests.

• Depending on the behavior of your code and networking libraries used by your code, Performance Monitoring might only report on network requests that are completed. This means that HTTP/S connections that are left open might not be reported.

Network request data are not aggregating as expected

Learn more about how Performance Monitoring aggregates network request data under URL patterns.

You can also try out custom URL patterns!

What happened to Top Issues in the Performance card on Project home?

We replaced Top Issues with Recent Alerts as a follow-up to our recent introduction of alerts, which automatically notify you when the thresholds you set are crossed. Issues are now deprecated and replaced by alerts.

The apps selector at the top of the Performance card filters the alert entries under Recent Alerts. Only the three most recent alerts for the app(s) selected are displayed.

To learn more about alerts, see Set up alerts for performance issues.

What happened to the ability to set thresholds for issues in the console?

Performance Monitoring supports alerts for metrics that exceed defined thresholds. To avoid confusion with these configurable thresholds for performance metrics, we removed the ability to configure thresholds for issues.

What happened to the Details and Metrics information in the Firebase console?

We replaced the Details and Metrics pages with a newly redesigned, centralized user interface (UI) to improve how you troubleshoot issues. This new troubleshooting UI offers the same core functionality that Details and Metrics offered. To learn more about troubleshooting, see View more data for a specific trace.

Why is the number of samples not what I expect?

Performance Monitoring collects performance data from your app’s user devices. If your application has many users or if the app generates a large amount of performance activity, Performance Monitoring might limit data collection to a subset of devices to reduce the number of processed events. These limits are high enough so that, even with fewer events, the metric values are still representative of your user's app experience.

To manage the volume of data that we collect, Performance Monitoring uses the following sampling options:

• On-device rate limiting: To prevent a device from sending sudden bursts of traces, we limit the number of code and network request traces sent from a device to 300 events every 10 mins. This approach protects the device from looped instrumentations that can send large amounts of performance data, and it prevents a single device from skewing the performance measurements.

• Dynamic sampling: Performance Monitoring collects a limited number of code traces and network request traces per app daily across all app users. A dynamic sampling rate is fetched on devices (using Firebase Remote Config) to determine whether a random device should capture and send traces. A device that is not selected for sampling does not send any events. The dynamic sampling rate is app-specific and adjusts to ensure that the overall volume of collected data remains below the limit.

  User sessions send additional, detailed data from a user's device, requiring more resources to capture and send the data. To minimize the impact of user sessions, Performance Monitoring might also restrict the number of sessions.

• Server-side rate limiting: To ensure that apps don't exceed the sampling limit, Performance Monitoring might use server-side sampling to drop some events received from devices. Although this type of limiting doesn't change the effectiveness of our metrics, it may cause minor pattern shifts, including the following:

  • The number of traces can differ from the number of times that a piece of code was executed.
  • Traces that are closely coupled in code may each have a different number of samples.

What happened to the Issues tab in the console?

We replaced the Issues tab with the introduction of Alerts, which automatically notifies you when the thresholds you set are exceeded. You no longer need to manually check the Firebase console to determine the status of a threshold. To learn about Alerts, see Set up alerts for performance issues.

What happened to the On Device and Network tabs in the console? How do I view the traces that were on those pages?

We've redesigned the Performance Monitoring section of the Firebase console so that the Dashboard tab displays your key metrics and all your traces in one space. As part of the redesign, we removed the On device and Network pages.

The traces table at the bottom of the Dashboard tab has all the same information that the On device and Network tabs displayed, but with some added features, including the ability to sort your traces by the percentage change for a specific metric. To view all the metrics and data for a specific trace, click the trace name in the traces table.

View your traces in the following subtabs of the traces table:

• Network request traces (both out-of-the-box and custom) — Network requests subtab
• Custom code traces — Custom traces subtab
• App start, app-in-foreground, app-in-background traces — Custom traces subtab
• Screen rendering traces — Screen rendering subtab
• Page load traces — Page load subtab

For details about the traces table and viewing metrics and data, visit the console overview page (iOS+ | Android | Web).

Why is the number of slow and frozen frames not what I expected?

Slow rendering frames and frozen frames are calculated with an assumed device refresh rate of 60Hz. If a device refresh rate is lower than 60Hz, each frame will have a slower rendering time because fewer frames are rendered per second. Slower rendering times can cause more slow or frozen frames to be reported because more frames will be rendered slower or will freeze. However, if a device refresh rate is higher than 60Hz, each frame will have a faster rendering time. This can cause fewer slow or frozen frames to be reported. This is a current limitation in the Performance Monitoring SDK.

How do I add the smaller, namespaced Performance Monitoring JS SDK (the "standalone" SDK) to my web app?

If Performance Monitoring is the only Firebase product in your app, you can use the standalone Performance Monitoring SDK (and the recommended header script below) if you’re interested in:

• using a namespaced library
• reducing your SDK package size
• delaying initialization of the SDK until after your page loads

To include the standalone Performance Monitoring SDK in your app and delay its initialization to after your page loads:

1. Add the following script to the header of your index file.
2. Make sure to add your app's Firebase project configuration object.

(function(sa,fbc){function load(f,c){var a=document.createElement('script');
a.async=1;a.src=f;var s=document.getElementsByTagName('script')[0];
s.parentNode.insertBefore(a,s);}load(sa);
window.addEventListener('load',function(){firebase.initializeApp(fbc).performance()});
})(performance_standalone, firebaseConfig);

where,

• performance_standalone is 'https://www.gstatic.com/firebasejs/11.1.0/firebase-performance.js'
• firebaseConfig is your app's Firebase config object

The above script asynchronously loads the standalone SDK then initializes Firebase after the window's onload event fires. This tactic reduces the impact that the SDK could have on page load metrics since the browser has already reported its loading metrics when you initialize the SDK.

(function(sdkSource, firebaseConfigObject) {
   function load(f, c) {
       // Creates a script tag to load the standalone SDK
       var sdkScript = document.createElement('script');

       // Sets it to an async script so that it doesn't interfere with page load
       sdkScript.async = 1;

       // Sets the source of the script
       sdkScript.src = f;

       // Inserts the script into the head of the page
       var s = document.getElementsByTagName('script')[0];
       s.parentNode.insertBefore(sdkScript, s);
   }

   // Calls the load method
   load(sdkSource);

   // Initializes the SDK only when the onload method is called
   window.addEventListener('load', function() {
       firebase.initializeApp(firebaseConfigObject).performance();
   });
})(performance_standalone, firebaseConfig);

What does "near real-time" performance data mean?

Firebase Performance Monitoring processes collected performance data as it comes in, which results in near real-time data display in the Firebase console. Processed data displays in the console within a few minutes of its collection, hence the term "near real-time".

To take advantage of near real-time data processing, make sure your app uses a real-time compatible SDK version.

How do I get near real-time performance data for my app?

To take advantage of near real-time data processing, you only need to make sure that your app uses a Performance Monitoring SDK version that's compatible with real-time data processing.

These are the real-time compatible SDK versions:

• iOS — v7.3.0 or later
• tvOS — v8.9.0 or later
• Android — v19.0.10 or later (or Firebase Android BoM v26.1.0 or later)
• Web — v7.14.0 or later

Note that we always recommend using the latest version of SDK, but any version listed above will enable Performance Monitoring to process your data in near real time.

Which versions of the Performance Monitoring SDK are considered real-time compatible?

These are the SDK versions compatible with real-time data processing:

• iOS — v7.3.0 or later
• tvOS — v8.9.0 or later
• Android — v19.0.10 or later (or Firebase Android BoM v26.1.0 or later)
• Web — v7.14.0 or later

Note that we always recommend using the latest version of SDK, but any version listed above will enable Performance Monitoring to process your data in near real time.

What if I don't update my app to use a real-time compatible SDK version?

If your app doesn't use a real-time compatible SDK version, you will still see all your app's performance data in the Firebase console. However, the display of performance data will be delayed by roughly 36 hours from the time of its collection.

I've updated to a real-time compatible SDK version, but some of my users are still on old versions of my app. Do I continue to see their performance data in the Firebase console?

Yes! Regardless of which SDK version an app instance uses, you'll see performance data from all your users.

However, if you're looking at recent data (less than roughly 36 hours old), then the displayed data is from users of app instances using a real-time compatible SDK version. The non-recent data, though, includes performance data from all versions of your app.