﻿---
title: Keep Kibana fast
description: tl;dr: Load as much code lazily as possible. Everyone loves snappy applications with a responsive UI and hates spinners. Users deserve the best experience...
url: https://www.elastic.co/elastic/docs-builder/docs/2777/extend/kibana/plugin-performance
products:
  - Kibana
---

# Keep Kibana fast
**tl;dr**: Load as much code lazily as possible. Everyone loves snappy applications with a responsive UI and hates spinners. Users deserve the best experience whether they run Kibana locally or in the cloud, regardless of their hardware and environment.
There are 2 main aspects of the perceived speed of an application: loading time and responsiveness to user actions. Kibana loads and bootstraps **all** the plugins whenever a user lands on any page. It means that every new application affects the overall *loading performance*, as plugin code is loaded *eagerly* to initialize the plugin and provide plugin API to dependent plugins.
However, it’s usually not necessary that the whole plugin code should be loaded and initialized at once. The plugin could keep on loading code covering API functionality on Kibana bootstrap, but load UI related code lazily on-demand, when an application page or management section is mounted. Always prefer to import UI root components lazily when possible (such as in `mount` handlers). Even if their size may seem negligible, they are likely using some heavy-weight libraries that will also be removed from the initial plugin bundle, therefore, reducing its size by a significant amount.
```typescript
import type { Plugin, CoreSetup, AppMountParameters } from '@kbn/core/public';
export class MyPlugin implements Plugin<MyPluginSetup> {
  setup(core: CoreSetup, plugins: SetupDeps) {
    core.application.register({
      id: 'app',
      title: 'My app',
      async mount(params: AppMountParameters) {
        const { mountApp } = await import('./app/mount_app');
        return mountApp(await core.getStartServices(), params);
      },
    });
    plugins.management.sections.section.kibana.registerApp({
      id: 'app',
      title: 'My app',
      order: 1,
      async mount(params) {
        const { mountManagementSection } = await import('./app/mount_management_section');
        return mountManagementSection(coreSetup, params);
      },
    });
    return {
      doSomething() {},
    };
  }
}
```


## Understanding plugin bundle size

Kibana Platform plugins are pre-built with `@kbn/optimizer` and distributed as package artifacts. This means that it is no longer necessary for us to include the `optimizer` in the distributable version of Kibana. Every plugin artifact contains all plugin dependencies required to run the plugin, except some stateful dependencies shared across plugin bundles via `@kbn/ui-shared-deps-npm` and `@kbn/ui-shared-deps-src`. This means that plugin artifacts *tend to be larger* than they were in the legacy platform. To understand the current size of your plugin artifact, run `@kbn/optimizer` with:
```bash
node scripts/build_kibana_platform_plugins.js --dist --profile --focus=my_plugin
```

and check the output in the `target` sub-folder of your plugin folder:
```bash
ls -lh plugins/my_plugin/target/public/
# output
# an async chunk loaded on demand
... 262K 0.plugin.js
# eagerly loaded chunk
... 50K  my_plugin.plugin.js
```

You might see at least one js bundle - `my_plugin.plugin.js`. This is the *only* artifact loaded by Kibana during bootstrap in the browser. The rule of thumb is to keep its size as small as possible. Other lazily loaded parts of your plugin will be present in the same folder as separate chunks under `{{number}}.myplugin.js` names. If you want to investigate what your plugin bundle consists of, you need to run `@kbn/optimizer` with `--profile` flag to generate a [webpack stats file](https://webpack.js.org/api/stats/).
```bash
node scripts/build_kibana_platform_plugins.js --dist --no-examples --profile
```

Many OSS tools allow you to analyze the generated stats file:
- [An official tool](http://webpack.github.io/analyse/#modules) from Webpack authors
- [webpack-visualizer](https://chrisbateman.github.io/webpack-visualizer/)