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

# Optimize large trace logging with attachments

export const plans_0 = "Any"

export const deployments_0 = "Any"

export const data_plane_version_0 = undefined

export const use_case_0 = undefined

<Note>
  **Applies to:**

  * Plan - {plans_0}
  * Deployment - {deployments_0}
  * {data_plane_version_0}
  * {use_case_0}
</Note>

## Summary

**Issue:** Traces with large conversational data (ie hundreds of runs with hundreds of thousands of tokens each) can cause slow UI loading and poor browsing experience.

**Cause:** Large JSON payloads render inline, resulting in slow performance when opening traces.

**Resolution:** Use `JSONAttachment` to move large data out of inline rendering while keeping essential metadata searchable.

## Implementation

Use `JSONAttachment` for large conversational data and keep essential metadata inline for indexing and filtering:

**Python:**

```python theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}}
from braintrust import JSONAttachment

span.log(
    input={
        # Large data stored as attachment
        "transcript": JSONAttachment(large_conversation, filename="chat.json")
    },
    # Essential metadata stays inline for filtering/search
    metadata={
        "model": "gpt-4",
        "turns": 156,
        "summary": "Customer support chat about billing"
    }
)

```

**TypeScript:**

```javascript theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}}
import { JSONAttachment } from "braintrust";

span.log({
  input: {
    // Large data stored as attachment
    transcript: new JSONAttachment(largeConversation, { filename: "chat.json" })
  },
  // Essential metadata stays inline for filtering/search
  metadata: {
    model: "gpt-4",
    turns: 156,
    summary: "Customer support chat about billing"
  }
});

```

**Key benefits:**

* UI for trace loads quickly, since large data as attachments don't render inline
* Full conversation still accessible via attachment viewer in UI
* Essential metadata visible at a glance for filtering and search

## Relevant Links

* [JSON Attachments Documentation](/instrument/attachments#log-large-json-data)