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

# Start a Scalability analysis

> How to kick off the analysis, what info is asked at the start, and what to expect during the run.

<Warning>
  The Scalability analysis only becomes available after the **Security Check** completes. Finish the security cycle before proceeding.
</Warning>

## How to start

Open the **Scalability Check** page for your app and fill the kickoff form:

| Field                     | What to enter                                                                                    |
| ------------------------- | ------------------------------------------------------------------------------------------------ |
| **How many users today?** | Approximate number of currently active users. Zero is allowed — useful for pre-launch apps.      |
| **6-month target?**       | How many users you expect 6 months from now. Must be greater than or equal to the current count. |

Both fields accept numbers up to **10,000,000**. If you don't have a clear target yet, project doubling or tripling the current base — you can run a new analysis later with different numbers.

Click **Start analysis** to begin.

## What happens during the analysis

The run takes about **1 minute** and executes three tracks in parallel:

<Steps>
  <Step title="Performance">
    Collects Web Vitals (LCP, INP, CLS) and bundle size through a controlled execution of your app.
  </Step>

  <Step title="Coupling">
    Evaluates code architecture — where coupling points will make growth harder.
  </Step>

  <Step title="Data">
    Maps data flow and identifies patterns that may bottleneck as the user base grows.
  </Step>
</Steps>

In parallel, the analyzer also detects the **third-party APIs** your app consumes to prepare the next step (Plan Review).

The progress bar shows the overall percentage. When all subscores are computed, you're automatically redirected to the Plan Review wizard.

## Possible statuses

| Status                | Meaning                                                                                                                   |
| --------------------- | ------------------------------------------------------------------------------------------------------------------------- |
| **Running**           | The analysis is in progress — wait for the redirect.                                                                      |
| **Analysis failed**   | Something went wrong. Use the **Reload** button or start a new analysis. If it persists, verify the app URL is reachable. |
| **Analysis complete** | The analysis finished successfully. You're taken straight to Plan Review.                                                 |

## After the technical analysis

When the technical analysis ends, **the report is not ready yet**. The next two steps ask for your confirmation so the report numbers reflect your reality — not the analyzer's guesses.

<Tip>
  If you closed the browser mid-flow, just go back to your app — the portal takes you straight to where you left off (Plan Review or Tune Assumptions).
</Tip>

## Next steps

<CardGroup cols={2}>
  <Card title="Plan Review" icon="list-checks" href="/en/scalability/plan-review">
    Confirm the real tier of each API your app uses.
  </Card>

  <Card title="Tune Assumptions" icon="sliders" href="/en/scalability/tune-assumptions">
    Refine consumption estimates per user before seeing the report.
  </Card>
</CardGroup>