> For the complete documentation index, see [llms.txt](https://docs.hackle.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.hackle.io/en/ab-test/status/health-check.md).

# Health Check

Use the Health Check to verify that everything is ready to start an A/B Test, or that the test is running correctly.

{% stepper %}
{% step %}

### User Identifier Delivery

Checks whether the User Identifier selected as the distribution basis for the A/B Test is being sent to Hackle correctly.

![](https://143363954-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FyAVlNQhS253reum0Ce94%2Fuploads%2Fgit-blob-37dee4efde13b7401e9eb7316378ff9d1248b550%2Fba46614-Healthcheck_01_b8a8432081eb2102.png?alt=media)

{% hint style="danger" %}
**If the alert is red**

1. Refer to the [User Identifier](/en/getting-started/user-identifier.md) document to send User Identifier information.
2. Check the [Real-time Exposure Status](/en/ab-test/management/realtime-status.md) from the button below. Verify that the User Identifier selected as the distribution basis exists.
   {% endhint %}

![](https://143363954-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FyAVlNQhS253reum0Ce94%2Fuploads%2Fgit-blob-d8c078968d3edefec034e2cbdeb3099480faf840%2F7a36f5a-Healthcheck_05_5899e5ec9ffb8348.png?alt=media)

{% hint style="warning" %}
**If the alert is yellow**

1. Check [Real-time Exposure Status](/en/ab-test/management/realtime-status.md) for users exposed within the last 1 hour. If there are none, check again after a user has been exposed.
2. If there are exposed users, check the User Identifier delivery. A code change may have caused the delivery to fail. Refer to the [User Identifier](/en/getting-started/user-identifier.md) document.
   {% endhint %}
   {% endstep %}

{% step %}

### Event Delivery

Checks whether the events used when registering goals, retention, and funnels in the A/B Test are being sent correctly.

![](https://143363954-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FyAVlNQhS253reum0Ce94%2Fuploads%2Fgit-blob-c37f5c16e616889f8ec36ff72b4827d27d6be482%2F2a8b7f5-Healthcheck_02_0403533da1f9c3ca.png?alt=media)

{% hint style="danger" %}
**If the alert is red**

1. Send the event items in the box below to Hackle. Click an item to check its real-time status.
2. If items remain after delivery, check the User Identifier information. Events must include the User Identifier information used as the distribution basis. Refer to the [User Identifier](/en/getting-started/user-identifier.md) document.
   {% endhint %}

![](https://143363954-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FyAVlNQhS253reum0Ce94%2Fuploads%2Fgit-blob-02209235d365dce25164a1de3ff38b834d94062a%2F19c0efb-Healthcheck_06_f35117ad0f1bd33b.png?alt=media)

{% hint style="warning" %}
**If the alert is yellow**

1. Click each event item to check whether the event has been sent within the last 1 hour.
2. If the item still appears even though there is a delivery history, check the User Identifier information. Events must include the User Identifier information used as the distribution basis. Refer to the [User Identifier](/en/getting-started/user-identifier.md) document.
   {% endhint %}
   {% endstep %}

{% step %}

### A/B Test Exposure

Checks whether at least one user has been exposed to the A/B Test and distributed to a test group. You can verify whether users have actually participated in the A/B Test in the production environment. This can be checked 1 hour after the A/B Test starts.

![](https://143363954-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FyAVlNQhS253reum0Ce94%2Fuploads%2Fgit-blob-82c3978a13102f5b5387c8105ec94c39f6318795%2F235c98c-Healthcheck_03_8498e064591cb5df.png?alt=media)

1. Check that both the User Identifier delivery and Event delivery items are normal.
2. Verify that at least 1% of traffic has been allocated. If the test has started but traffic is still at 0%, users will not be exposed to the A/B Test.
3. Check that the A/B Test Targeting is working correctly. Property information used in targeting conditions must be collected. Refer to the [Set Targeting](/en/ab-test/create-and-configure/ab-targeting.md) document.
   {% endstep %}

{% step %}

### Data Calculation

Checks the calculation results of the registered goals, retention, and funnels. For any item whose result is `0`, go through the checks below in order.

![](https://143363954-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FyAVlNQhS253reum0Ce94%2Fuploads%2Fgit-blob-153620861eae7484b00b0de317b2769da0b54775%2Fa0acc98-Healthcheck_04_48b64a773040ea9b.png?alt=media)

1. Verify that the A/B Test integration, event delivery, and A/B Test exposure are all normal.
2. For items with a filter applied, check the event property used in the filter. Open the relevant event in [Event Management](/en/event-management/event-management.md) and check its [Event Property](/en/event-management/properties/event-property.md).
   {% endstep %}
   {% endstepper %}


---

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