Update trace metadata

Update metadata on a trace after creation. Inserts a synthetic span carrying the new attributes through the standard ingestion pipeline. New keys are added, existing keys are updated, missing keys are preserved. Labels replace entirely.

PATCH /api/v1/traces/{traceId}/metadata

Python

Python

import requests

url = "https://app.langwatch.ai/api/v1/traces/{traceId}/metadata"

payload = { "metadata": {} }
headers = {
    "X-Auth-Token": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.patch(url, json=payload, headers=headers)

print(response.text)

200

{
  "traceId": "<string>"
}

Authorizations

X-Auth-Token · string · header · required

Project API key for sending traces and accessing project-scoped resources. Format: sk-lw-... (no underscore). Obtain one by creating a project via the Admin API or the LangWatch UI.

Path Parameters

traceId · string · required

The trace ID — either the full 32-char ID or a unique prefix (≥ 8 chars). Prefix lookup is scoped to the authenticated project.

Minimum string length: 1

Body

application/json

metadata · object · required

Show child attributes

Response

200 - application/json

Success

traceId · string · required