Netlify Plugin Lighthouse

> [!IMPORTANT]
> Contributions and bug reports to the project are not being accepted at this time.

A Netlify plugin to generate a Lighthouse report for every deploy

Installation options

You can install the plugin for your site using your netlify.toml file or the Netlify UI.

For the most customization options, we recommend installing the Lighthouse plugin with a netlify.toml file.

netlify.toml file-based installation allows you to:

- Run Lighthouse audits for different site paths, such as the contact page and site home page
- Run Lighthouse audits for a desktop device
- Generate Lighthouse results in a language other than English

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For UI-based installation, you can install this plugin from the Integrations Hub, the Plugins directory, or through this direct installation link.

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To install the plugin manually:

From your project's base directory, use npm, yarn, or any other Node.js package manager to add the plugin to devDependencies in package.json.

``bash
npm install -D @netlify/plugin-lighthouse
`

Then add the plugin to your netlify.toml configuration file:

`toml
[[plugins]]
package = "@netlify/plugin-lighthouse"

# optional, deploy the lighthouse report to a path under your site
[plugins.inputs.audits]
output_path = "reports/lighthouse.html"
`

The lighthouse scores are automatically printed to the Deploy log in the Netlify UI. For example:

`
2:35:07 PM: ────────────────────────────────────────────────────────────────
2:35:07 PM: @netlify/plugin-lighthouse (onSuccess event)
2:35:07 PM: ────────────────────────────────────────────────────────────────
2:35:07 PM:
2:35:07 PM: Serving and scanning site from directory dist

...

2:35:17 PM: {
2:35:17 PM: results: [
2:35:17 PM: { title: 'Performance', score: 0.91, id: 'performance' },
2:35:17 PM: { title: 'Accessibility', score: 0.93, id: 'accessibility' },
2:35:17 PM: { title: 'Best Practices', score: 0.93, id: 'best-practices' },
2:35:17 PM: { title: 'SEO', score: 0.81, id: 'seo' },
2:35:17 PM: { title: 'Progressive Web App', score: 0.4, id: 'pwa' }
2:35:17 PM: ]
2:35:17 PM: }
`

Lighthouse plugin configuration options

To customize how Lighthouse runs audits, you can make changes to the netlify.toml file.

By default, the plugin will run after your build is deployed on the live deploy permalink, inspecting the home path /.
You can add additional configuration and/or inspect a different path, or multiple additional paths by adding configuration in the netlify.toml file:

`toml
[[plugins]]
package = "@netlify/plugin-lighthouse"

# Set minimum thresholds for each report area
[plugins.inputs.thresholds]
performance = 0.9

# to audit a path other than /
# route1 audit will use the top level thresholds
[[plugins.inputs.audits]]
path = "route1"

# you can optionally specify an output_path per audit, relative to the path, where HTML report output will be saved
output_path = "reports/route1.html"

# to audit a specific absolute url
[[plugins.inputs.audits]]
url = "https://www.example.com"

# you can specify thresholds per audit
[plugins.inputs.audits.thresholds]
performance = 0.8

`

#### Fail a deploy based on score thresholds

By default, the lighthouse plugin will run _after_ your deploy has been successful, auditing the live deploy content.

To run the plugin _before_ the deploy is live, use the fail_deploy_on_score_thresholds input to instead run during the onPostBuild event.
This will statically serve your build output folder, and audit the index.html (or other file if specified as below). Please note that sites or site paths using SSR/ISR (server-side rendering or Incremental Static Regeneration) cannot be served and audited in this way.

Using this configuration, if minimum threshold scores are supplied and not met, the deploy will fail. Set the threshold based on performance, accessibility, best-practices, seo, or pwa.

`toml
[[plugins]]
package = "@netlify/plugin-lighthouse"

# Set the plugin to run prior to deploy, failing the build if minimum thresholds aren't set
[plugins.inputs]
fail_deploy_on_score_thresholds = "true"

# Set minimum thresholds for each report area
[plugins.inputs.thresholds]
performance = 0.9
accessibility = 0.7

# to audit an HTML file other than index.html in the build directory
[[plugins.inputs.audits]]
path = "contact.html"

# to audit an HTML file other than index.html in a sub path of the build directory
[[plugins.inputs.audits]]
path = "pages/contact.html"

# to serve only a sub directory of the build directory for an audit
# pages/index.html will be audited, and files outside of this directory will not be served
[[plugins.inputs.audits]]
serveDir = "pages"
`

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By default, Lighthouse takes a mobile-first performance testing approach and runs audits for the mobile device experience. You can optionally run Lighthouse audits for the desktop experience by including preset = "desktop" in your netlify.toml file:

`toml
[[plugins]]
package = "@netlify/plugin-lighthouse"

[plugins.inputs.settings]
preset = "desktop" # Optionally run Lighthouse using a desktop configuration
`

Updates to netlify.toml will take effect for new builds.

To return to running Lighthouse audits for the mobile experience, just remove the line preset = "desktop". New builds will run Lighthouse for the mobile experience.

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By default, Lighthouse results are generated in English. To return Lighthouse results in other languages, include the language code from any Lighthouse-supported locale in your netlify.toml file.

For the latest Lighthouse supported locales or language codes, check out this official Lighthouse code.

Updates to netlify.toml will take effect for new builds.

#### Example to generate Lighthouse results in Spanish

`toml
[[plugins]]
package = "@netlify/plugin-lighthouse"

[plugins.inputs.settings]
locale = "es" # generates Lighthouse reports in Español
`

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Fork and clone this repo.

Create a .env file based on the example and run

`bash
yarn install
yarn local
``

Preview Lighthouse results within the Netlify UI

The Netlify UI allows you to view Lighthouse scores for each of your builds on your site's Deploy Details page with a much richer format.

You'll need to first install the Lighthouse build plugin on your site.

If you have multiple audits (e.g. multiple paths) defined in your build, we will display a roll-up of the average Lighthouse scores for all the current build's audits plus the results for each individual audit.