> ## Documentation Index
> Fetch the complete documentation index at: https://narev.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Import Langfuse traces into a Narev benchmark

> Pull production LLM traces from Langfuse into a Narev benchmark dataset so you can evaluate new models against your real user prompts and conversations.

<Tip>
  Use your production traces as test datasets. Instead of guessing which model works better, test against the prompts
  your users are actually sending.
</Tip>

## Prerequisites

* An active Langfuse account with production traces
* Langfuse API credentials (Secret Key and Public Key)
* Production traces in your Langfuse project

## Setup

1. Create a new **A/B test**
2. Navigate to **Setup** tab
3. In the **Data Source** section select **Import from traces**
4. Select **Langfuse** as provider
5. Enter your credentials:
   * **Project Name**: Your Langfuse project identifier
   * **Secret Key**: Your Langfuse secret key (for example, `sk-lf-<token>`)
   * **Public Key**: Your Langfuse public key (for example, `pk-lf-<token>`)
   * **Host**: Your Langfuse instance URL (default: `https://cloud.langfuse.com`)
6. Select your **Date Range** (default: last 7 days)
7. Click **Save Project** to import traces

<Frame>
  <img src="https://mintcdn.com/narev/Y1illty3WLN-yruS/images/benchmark/integration/langfuse.webp?fit=max&auto=format&n=Y1illty3WLN-yruS&q=85&s=eb33301167a96bbbf4f1a38a2db2e153" alt="Import traces from Langfuse interface" width="1570" height="1620" data-path="images/benchmark/integration/langfuse.webp" />
</Frame>

## Self-hosted support

Narev supports both Langfuse Cloud and self-hosted instances. When connecting your project, update the **Host** field to your self-hosted Langfuse URL.

## Common questions

<AccordionGroup>
  <Accordion title="Do I need to modify my Langfuse setup?">
    No. Narev reads from your existing Langfuse project without any changes to your instrumentation.
  </Accordion>

  <Accordion title="Can I test models not in my current Langfuse traces?">
    Yes. Narev imports prompts and usage patterns from Langfuse, then lets you test any supported model provider on
    those same prompts.
  </Accordion>

  <Accordion title="Will Narev send data back to Langfuse?">
    No. Narev imports traces to run experiments but doesn't write back to Langfuse.
  </Accordion>

  <Accordion title="Does this work with Langfuse trace hierarchy (spans, generations, events)?">
    Yes. Narev imports all types of Langfuse operations including nested traces, generations, and individual LLM calls.
  </Accordion>
</AccordionGroup>