---
title: hydrogen debug cpu
description: >-
  Builds the app and runs the resulting code to profile the server startup time,
  watching for changes. This command can be used to [debug slow app startup
  times](/docs/custom-storefronts/hydrogen/debugging/cpu-startup) that cause
  failed deployments in Oxygen.

    The profiling results are written to a `.cpuprofile` file that can be viewed with certain tools such as [Flame Chart Visualizer for Visual Studio Code](https://marketplace.visualstudio.com/items?itemName=ms-vscode.vscode-js-profile-flame).
api_name: shopify-cli
source_url:
  html: 'https://shopify.dev/docs/api/shopify-cli/hydrogen/hydrogen-debug-cpu'
  md: 'https://shopify.dev/docs/api/shopify-cli/hydrogen/hydrogen-debug-cpu.md'
---

# hydrogen debug cpucommand

Builds the app and runs the resulting code to profile the server startup time, watching for changes. This command can be used to [debug slow app startup times](https://shopify.dev/docs/custom-storefronts/hydrogen/debugging/cpu-startup) that cause failed deployments in Oxygen.

The profiling results are written to a `.cpuprofile` file that can be viewed with certain tools such as [Flame Chart Visualizer for Visual Studio Code](https://marketplace.visualstudio.com/items?itemName=ms-vscode.vscode-js-profile-flame).

## Flags

The following flags are available for the `hydrogen debug cpu` command:

* \--entry \<value>

  string

  env: SHOPIFY\_HYDROGEN\_FLAG\_ENTRY

  Entry file for the worker. Defaults to `./server`.

* \--output \<value>

  string

  Specify a path to generate the profile file. Defaults to "startup.cpuprofile".

* \--path \<value>

  string

  env: SHOPIFY\_HYDROGEN\_FLAG\_PATH

  The path to the directory of the Hydrogen storefront. Defaults to the current directory where the command is run.

### Examples

* #### hydrogen debug cpu

  ##### hydrogen debug cpu

  ```bash
  shopify hydrogen debug cpu [flags]
  ```