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

# Braintrust

> Import historical project logs from Braintrust into a Latitude project.

## Overview

This guide shows you how to import your **Braintrust** history into Latitude. Latitude
reads the logs in a Braintrust project and maps each span to a Latitude span.

<Check>
  Importing only reads from Braintrust. Nothing is changed or deleted at the source.
</Check>

***

## Requirements

* A **Braintrust project** with the logs you want to import
* A Braintrust **API key** (`sk-…`) with read access to that project
* Your Braintrust **data plane** — EU or US, found under **Settings → Data plane**

***

## Steps

<Steps>
  <Step title="Create an API key in Braintrust">
    In Braintrust, open **Settings → API keys** and create a key.
  </Step>

  <Step title="Connect">
    In Latitude, go to **Project settings → Imports**, choose **Braintrust** and your data
    plane, enter the API key, then press **Test connection**.
  </Step>

  <Step title="Preview and start">
    Pick the Braintrust project, set the time range and trace limit, check the preview,
    then press **Start import**.
  </Step>
</Steps>

***

## Braintrust specifics

* Session and user identity are read from `metadata.session_id` and `metadata.user_id`;
  token usage and Braintrust's own cost estimate come through directly.
* Images and files are fetched from Braintrust while the import runs and stored with the
  message (up to 2 MB each), so imported conversations do not depend on your Braintrust
  account afterwards.

<Note>
  Braintrust flattens messages logged over **OpenTelemetry** and can drop reasoning blocks
  doing so. Set `braintrust.otel.preserve_attributes: true` in your instrumentation and
  reasoning imports intact. Logs written with Braintrust's own SDK are unaffected.
</Note>

***

## Seeing your traces

Once imported, traces appear in your project's **Traces** view like any live trace, marked
with `import.*` metadata naming Braintrust and their original ids.