Filter out bots

4 min

Third-party bots can skew your experiment results by crawling your website and triggering events you only want to count for real users. Optimizely filters out bots on the IAB/ABC blocklist. To block bots, include the user agent for an event when you send that event to Optimizely.

For information on how Optimizely filters bots, see Filter bots and spidersFilter bots and spiders.

Note Bot filtering does not apply to past bot events, so you should configure it before you start the experiment. Otherwise, if you enable filtering halfway through an experiment, you might have to discard (or export and manually filter) any bot-contaminated event data from the start of the experiment.

Enable bot filtering

To exclude bot traffic, first enable the feature in the UIenable the feature in the UI. Then, depending on your SDK and where events are sent from, you may need to send additional information. If you are using the JavaScript SDK client-side, you are done. Otherwise, you must send the reserved $opt_user_agent attribute containing the user agent to the user context. See the following sections for step-by-step directions.

Enable in the UI

See Enable bot filtering in Feature ExperimentationEnable bot filtering in Feature Experimentation in the end-user documentation for steps to toggle bot filtering on or off for your project.

Client-side JavaScript events

No additional JavaScript code is required to enable bot filtering for events sent from browsers. When you track an event by calling the JavaScript SDK's `Track Event method`Track Event method the SDK automatically includes the user's user agent in the outbound request (see `Track Event method for SDK versions 5.3.5 and lower`Track Event method for SDK versions 5.3.5 and lower). If bot filtering is enabled for your project, Optimizely filters bots automatically.

All other events

When you track events with an SDK from somewhere other than a web browser, you must pass the user agent to the user context so Optimizely can filter bot traffic from your results. You should pass it using the reserved $opt_user_agent attribute in user-based methods. If bot filtering is enabled for your project and the user agent is passed this way, Optimizely applies bot filtering.

Important Before implementing the $opt_user_agent attribute, Enable bot filteringEnable bot filtering in your project first.

The following code example shows how to pass the $opt_user_agent attribute:

// Get the user agent and pass it to the Optimizely user context 
// as the attribute $opt_user_agent

let attributes = ["device"          : "iphone",
                  "location"        : "Chicago",
                  "$opt_user_agent" : "this_could_be_a_bot"]

user = optimizely.createUserContext(userId: "test-user-id", attributes: attributes)

// now any user-based call filters out the bot
let decision = user.decide(key: "flag_1")
try? user.trackEvent(eventKey: "my_purchase_event_key")

See each SDK's reference section for information.

Create a user context using the Android SDKCreate a user context using the Android SDK

Create a user context using the C# SDKCreate a user context using the C# SDK

Create a user context using the Flutter SDKCreate a user context using the Flutter SDK

Create a user context using the Go SDKCreate a user context using the Go SDK

Create a user context using the Java SDKCreate a user context using the Java SDK

Create a user context using the PHP SDKCreate a user context using the PHP SDK

Create a user context using the Python SDKCreate a user context using the Python SDK

Track event for the React SDKTrack event for the React SDK

Track event for the React Native SDKTrack event for the React Native SDK

Create a user context using the Ruby SDKCreate a user context using the Ruby SDK

Create a user context using the Swift SDKCreate a user context using the Swift SDK