lighthouse

Understanding the Results

The result object contains all the audit information Lighthouse determined about the page. In fact, everything you see in the HTML report, even the screenshots, is a rendering of information contained in the result object. You might need to work directly with the result object if you use Lighthouse programmatically, consume the JSON output of the CLI, explore Lighthouse results in HTTPArchive, or work on the report generation code that reads the Lighthouse JSON and outputs HTML.

Lighthouse Result Object (LHR)

The top-level Lighthouse Result object (LHR) is what the lighthouse node module returns and the entirety of the JSON output of the CLI. It contains some metadata about the run and the results in the various subproperties below.

For an always up-to-date definition of the LHR, take a look at our typedefs.

Properties

Name	Description
lighthouseVersion	The version of Lighthouse with which this result was generated.
fetchTime	The ISO-8601 timestamp of when the result was generated.
userAgent	The user agent string of the version of Chrome that was used by Lighthouse.
requestedUrl	The URL that was supplied to Lighthouse and initially navigated to.
finalUrl	The URL that Lighthouse ended up auditing after redirects were followed.
audits	An object containing the results of the audits.
configSettings	An object containing information about the configuration used by Lighthouse.
timing	An object containing information about how long Lighthouse spent auditing.
categories	An object containing the different categories, their scores, and references to the audits that comprise them.
categoryGroups	An object containing the display groups of audits for the report.
runtimeError	An object `{code: string, message: string};` providing a top-level error message that, if present, indicates a serious enough problem that this Lighthouse result may need to be discarded.
runWarnings	Array of top-level warnings for this Lighthouse run.

Example

{
  "lighthouseVersion": "5.1.0",
  "fetchTime": "2019-05-05T20:50:54.185Z",
  "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3358.0 Safari/537.36",
  "requestedUrl": "http://example.com",
  "finalUrl": "https://www.example.com/",
  "audits": {...},
  "configSettings": {...},
  "timing": {...},
  "categories": {...},
  "categoryGroups": {...},
}

`audits`

An object containing the results of the audits, keyed by their name.

Audit Properties

Example

{
  "is-on-https": {
      "id": "is-on-https",
      "title": "Does not use HTTPS",
      "description": "All sites should be protected with HTTPS, even ones that don't handle sensitive data. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/https).",
      "score": 0,
      "scoreDisplayMode": "binary",
      "displayValue": "1 insecure request found",
      "details": {
        "type": "table",
        "headings": [
          {
            "key": "url",
            "itemType": "url",
            "text": "Insecure URL"
          }
        ],
        "items": [
          {
            "url": "http://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"
          }
        ]
      }
    },
  },
  "custom-audit": {
    "name": "custom-audit",
    ...
  }
}

`configSettings`

An object containing information about the configuration used by Lighthouse.

Example

{
  "output": [
    "json"
  ],
  "maxWaitForLoad": 45000,
  "throttlingMethod": "devtools",
  "throttling": {
    "rttMs": 150,
    "throughputKbps": 1638.4,
    "requestLatencyMs": 562.5,
    "downloadThroughputKbps": 1474.5600000000002,
    "uploadThroughputKbps": 675,
    "cpuSlowdownMultiplier": 4
  },
  "gatherMode": false,
  "disableStorageReset": false,
  "emulatedFormFactor": "mobile",
  "blockedUrlPatterns": null,
  "additionalTraceCategories": null,
  "extraHeaders": null,
  "onlyAudits": null,
  "onlyCategories": null,
  "skipAudits": null
}

`timing`

An object containing information about how long Lighthouse spent auditing.

Properties

Example

{
  "total": 32189
}

`categories`

An array containing the different categories, their scores, and the results of the audits in the categories.

CategoryEntry Properties

AuditEntry Properties

Example

{
  "pwa": {
    "id": "pwa",
    "title": "Progressive Web App",
    "description": "PWAs are awesome. [Learn more](...)",
    "score": 0.54,
    "auditRefs": [
      {
        "id": "is-on-https",
        "weight": 1
      }
    ]
  }
}

`categoryGroups`

An object containing the display groups of audits for the report, keyed by the group ID found in the config.

GroupEntry Properties

Example

{
  "metrics": {
    "title": "Metrics",
    "description": "These metrics are super cool."
  },
}

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