Question about campaign report values & A/B message aggregation

Hi Klaviyo Devs,

We’re currently building our first Klaviyo integration, and overall the experience has been very smooth so far — thank you for the great APIs and documentation.

We’re running into some confusion specifically around querying campaign report values, and we were hoping you could provide some guidance or clarification.

What we’re trying to achieve

For a given campaign, we’d like to retrieve metrics such as:

• Open rate

• Bounce / failed rate

In particular, we’re unsure how this should work when:

• A campaign uses A/B testing

• The campaign contains multiple messages

• We want aggregated metrics at the campaign level (or clarity on how to aggregate per-message metrics correctly)

What we’ve tried

We attempted to use the campaign-values-reports endpoint to retrieve these metrics, but haven’t been able to get it working as expected.

Example request we tried:

curl --location 'https://a.klaviyo.com/api/campaign-values-reports' \
--header 'revision: 2025-10-15' \
--header 'Content-Type: application/vnd.api+json' \
--header 'Accept: application/vnd.api+json' \
--header 'Authorization: Klaviyo-API-Key <API_KEY>' \
--data '{
  "data": {
    "type": "campaign-values-report",
    "attributes": {
      "statistics": [
        "conversion_uniques",
        "failed_rate"
      ],
      "timeframe": {
        "key": "last_week"
      },
      "conversion_metric_id": "<string>",
      "filter": "<string>"
    }
  }
}'

However, this does not return usable results for our use case, and we’re not confident we’re using the correct approach.

Questions

1. What is the recommended way to retrieve open rate and bounce/failed rate for a campaign?

2. How should metrics be handled for A/B campaigns with multiple messages?

   • Are metrics aggregated automatically at the campaign level?

   • Or should we fetch metrics per message and aggregate ourselves?

3. Is campaign-values-reports the correct endpoint for this, or should we be using a different API altogether?

We’d really appreciate any guidance or examples you can share. Happy to provide more context if needed.

Thanks in advance for your help,
Tanmay