---
title: "Start performance trace"
method: POST
path: "/v1/browser/trace/start"
tags: ["Browser"]
---

# Start performance trace

`POST /v1/browser/trace/start`

## Request

- Base URL: `http://localhost:9998`
- URL: `http://localhost:9998/v1/browser/trace/start`
- Auth: HTTP bearer

Begins collecting performance metrics and web vitals via CDP.

## Response `200`

Trace started

- object
  - `active` true, required

## Other responses

- `400`: Trace error (e.g. already tracing)
- `409`: Not connected to a browser
- `503`: Browser service not initialized

---

[API](https://skmtc.dev/modelpiper/apis/toolpiper-api.md) · [All operations](https://skmtc.dev/modelpiper/apis/toolpiper-api/llms.txt) · [OpenAPI document](https://skmtc.dev/modelpiper/apis/toolpiper-api/revisions/6722bf56385c?raw)