# Performance (/docs/performance-errors/performance)



# Performance [#performance]

Ucoder Insight automatically collects browser performance signals for every project — no configuration is required to start tracking. The SDK records Web Vitals such as LCP, CLS, INP, FCP, and TTFB.

## Configuration [#configuration]

Performance tracking is **on by default for all plans** and does not need to be enabled manually.

Only **Pro plan** projects can opt out locally, using `trackPerformance: false` in the SDK config:

```ts
import { initUcoderInsight } from "ucoder-insight";
initUcoderInsight("YOUR_PUBLIC_TRACKING_ID", {
  trackPerformance: false,
});
```

<Callout type="warn">
  `trackPerformance: false` only takes effect on Pro plan projects. On Free plan
  projects, this option is ignored and performance data continues to be
  collected. Setting `trackPerformance: true` has no effect on any plan, since
  tracking is already enabled by default — it is not a supported override.
</Callout>

| Plan | Default     | Can opt out with `trackPerformance: false`? |
| :--- | :---------- | :------------------------------------------ |
| Free | Tracking on | No — option is ignored                      |
| Pro  | Tracking on | Yes                                         |

## Reading the values [#reading-the-values]

Compare values by page, device, and date range. LCP describes when the main content becomes visible, CLS describes unexpected layout movement, INP describes interaction responsiveness, FCP describes first visible content, and TTFB describes the time before the first response bytes arrive.

Performance data is sampled browser data, not a synthetic benchmark. Investigate slow segments by checking the page assets, server response time, and device conditions.