Google Lighthouse – SEO Glossary | Searchmetrics

Lighthouse is an open source tool for running technical website audits. The tool was developed by Google, and it analyzes the following aspects of a URL: ... GoogleLighthouse Lighthouseisanopensourcetoolforrunningtechnicalwebsiteaudits.ThetoolwasdevelopedbyGoogle,anditanalyzesthefollowingaspectsofaURL:Performance,ProgressiveWebApp,Accessibility,BestPracticesandSEO. TheLighthouseframeworkhasalreadybeenintegratedintoGoogle’sotherperformanceanalysistools,suchastheanalysisforPageSpeedInsightsandthebrowser-basedauditsviatheChromebrowser’sdevelopertools. RequestyourLighthouseReport WhatisGoogleLighthouse? Lighthousemakesitpossibletoaudittheperformanceofwebsites.Lighthouse1.0wasfirstdevelopedasanaudittoolforProgressiveWebApps(PWAs).Version2.0thenalsoincludedaperformanceandSEOanalysisfornormalwebsites.Thethirditeration,LighthouseVersion3.0,wasreleasedinearly2018,andprovidedanewlayoutanddirectintegrationintothedevelopertoolsofGoogle’sChromebrowser.LighthouseremainsanopensourceanalysisframeworkthatrunsatURLlevel. WhichauditscanGoogleLighthouserun? TheauditsofferedbyLighthousearegroupedintofiveoptimizationcategories:Performance,BestPractices,Accessibility,SEOandProgressiveWebApps. Userscanselectone,moreorallfivecategories,dependingonwhichaspectsoftheirwebsitetheywishtoanalyze. Performance Inthiscategory,Lighthouseanalyzeshowquicklyawebsiteorapploadsandhowquicklyuserscanaccessorviewthecontent.Here,Lighthouseanalyzessixspeedmetrics: FirstContentfulPaint:Thisindicatesthetimebeforethefirsttextorimagebecomesvisibletousers. FirstMeaningfulPaint:Thisindicatesthetimewhenthemaincontentofapagebecomesvisibletousers. SpeedIndex:Thespeedindexprovidesauniformmetrictoexpresshowquicklythecontentofapageisloaded. TimetoInteractive:Thisindicatesthetimebeforetheuserisabletofullyinteractwiththepageanditscontent. FirstCPUIdle:Thevalueinthiscategoryreturnsthetimewhenthepage’smainthreadactivityislowenoughtoenableinputstobeprocessed. EstimatedInputLatency:Thepreviousresultisanestimate(inmilliseconds)ofhowlonganappneedstobereacttouserinputsduringthe5-secondwindowofmaximumcomputationduringpageload.Ifthelatencyisover50ms,usersmayperceiveanapporwebsitetobetooslow. Lighthouse’sperformanceanalysisalsoincludesrecommendationsforimprovements.Theseshowmanyopportunitiesforreducingloadtimes–suchasbycompressingimages,bycleaningupJavaScriptorCSS,orbyreducingrender-blockingresources,suchasJavaScripts,externalrequestsorCSScommands.Correctlyimplementedcaching,serverresponsetimesandavoiding(orlimiting)redirectsarealsorecommendedwaysofimprovingsiteperformance. TheperformancerecommendationsfromLighthousearethefollowing: Reducerender-blockingresources Serveimagesinnext-genformats Enabletextcompression DeferunusedCSS Ensuretextremainsvisibleduringwebfontloading Useefficientcachepolicyonstaticassets ImprovetheCriticalRenderingPath(CRP) Avoidoversizedimages Delayloadofoffscreenimages Minify/compressCSS Minify/compressJavaScript Optimizeimages Enableserverpre-connect Keepserverresponsetimeslow(TimeToFirstByte,TTFB) Avoidredirects Preloadkeyrequests Usevideoformatsforanimatedcontent Reducethetotalbyteweight AvoidanexcessiveDOMsize Measureperformancewithusertimingmarksandmeasures ReduceJavaScriptbootuptime Reducethepayloadofthemainthread BestPractices The16BestPracticestestedbyLighthousemainlyconcentrateonsecurityaspectsofwebsitesandmodernstandardsofwebdevelopment.LighthouseanalyzeswhetherHTTPSandHTTP/2areused,checkstoseewhetherresourcescomefromsecuresourcesandassessesthevulnerabilityofJavaScriptlibraries.Otherbestpracticeslookatsecuredatabaseconnectionsandavoidingtheuseofnon-securecommands,suchasdocument.write(),orincorporatingantiquatedAPIs. SEO Lighthouserunsvariousteststoestablishhowwellawebsiteorappcanbecrawledbysearchenginesanddisplayedinthesearchresults.TheseLighthouseteststhatGoogledescribesas“SEO”areextremelylimited;anyonewithawebsiteorappthatdoesnotachieveamaximumscoreshouldmaketherequiredfixes.Oncethesechangeshavebeenmade,searchengineoptimizationoffershugepotentialforotherimprovements,whichshouldcertainlybeexplored. Lighthousecurrentlyruns13auditswithinthesearchengineoptimizationcategory.Thesemainlylookatmobile-friendlinessorPWA,thecorrectapplicationofstructureddataandtagslikecanonicals,hreflang,titlesandmetadescriptions,andwhetherapagecanbecrawledbysearchenginebots. Accessibility Lighthouse’saccessibilityauditsexaminehowwellawebsiteorappcanbeusedbypeoplewithdisabilities.Thisincludestestsonimportantelementslikebuttonsorlinks,toseewhethertheyaresufficientlywelldescribed,orwhetherimageshavebeenassignedanalt-attributesothatthevisualcontentcanalsobedescribedbyscreenreadersforvisuallyimpairedusers. ProgressiveWebApps ThissectionwasoriginallythecoreofGoogleLighthouse–theanalysisofProgressiveWebApps,orPWAs.Doesthewebsiteregisteraserviceworker?Doesitworkofflinewithinternetaccess?Doesitreturna200error?TheseauditswerehowLighthousebegan,buttheyarenowjustoneofthefiveauditcategoriesandonewhichisonlyofrealimportanceforprovidersofProgressiveWebApps. HowcanGoogleLighthousebeaccessed? PageSpeedInsights:Google’sPageSpeedInsightsusedtojustreturnasinglescore,butnowthistooldrawsontheanalysisfunctionsinLighthouse.AnyURLcanbetestedforananalysisofsixperformancevaluesandtheresultsofnumerousadditionalauditsandrecommendations.AnoverallSpeedScoreisalsocompiledfromthesixperformancemetrics.YoucanaccessPageSpeedInsightshere. DeveloperToolsintheChromebrowser:SinceApril2018,GoogleLighthousehasalsobeenavailableviathedevelopertoolsinGoogle’sChromebrowser.Here,userscanselectwhichofthefivemaincategoriestheywouldliketorunauditsin.Therearealsodeviceoptions,withusersabletochoosemobileordesktop,andarangeofsimulatedinternetspeedstobeusedfortheanalysis.Here’showyoucanfindtheLighthouseauditsinChromeDevTools. ChromePlugin:CompleteLighthouseauditscanalsoberunusingtheChromePlugin.YoucanfindLighthouseChromePluginhere(ifyouareusingtheChromebrowser). Lighthouse’sPerformanceAuditscanalsoberunviaGoogle’sweb.devportal.Hereyoucanfindthemostimportantauditswithallresultsandrecommendations. HowcanIauditacompletewebsite? LighthouseisapowerfultoolforanalyzingtheperformanceofwebsitesandPWAs.However,thetooldoeshaveonemajordisadvantage–itcanonlyberunatURLlevel. WithitsLighthouseAudits,Searchmetricshasdevelopedawayofanalyzingcompletedomainsandtheirrelevantonlinemarkets,toestablishtheoptimizationlevelofanindustryandtheperformanceofadomaincomparedwithitscompetitors. RequestyourLighthouseReport BuildyourKnowledgewithourMarketingPacks. ImproveyourwebsiteperformancethroughUXOptimizations 27resources OnlineMarketing:provenstrategiesandsolutionsforbusinesses 27resources HowdoGoogleupdatesaffectbusinessrankingsandrevenue? 18resources Growyourpipelineandincreaserevenuethroughorganicsearchanddemandoptimization 40resources A AcceleratedMobilePages AgileContentDevelopment AltAttributes AnchorText B Backlinks BadNeighborhood Blockers Briefing BrokenLinks Businessdirectory C Cloaking Competition ContentEditor ContentGapAnalysis ContentMarketing ContentRelevance ContentScore Conversion Cookies Crawlers D DefectiveLinks DomainPopularity DomainTrust DuplicateContent F FeaturedSnippets Frame G GoogleAds(AdWords) GoogleKeywordPlanner GoogleKnowledgeGraph GoogleLighthouse Google+-Local(GooglePlaces) GoogleMaps GoogleMobileUpdates GoogleMyBusiness GoogleNews GooglePandaUpdate GooglePenguinUpdate GooglePhantomUpdate GooglePlaces GoogleSearchConsole GoogleShopping GoogleTrends GoogleUpdatesOverview Google'sHummingbirdAlgorithmStudy H Homepage I Index Internallinks K Keyword KeywordCannibalization KeywordDensity KeywordProximity KeywordStuffing L LinkJuice LinkPopularity Linktext M MetaDescription MetaSearchTerm MetaTag MetaTitle O OffpageOptimization OnpageOptimization P Page PageContent PageTitle PaidListing PlagiarismFinder ProgressiveWebApps R RankingFactor RankingOpportunities Rankings RichSnippets Robots.txt S SearchEngine SearchEngineAdvertising SearchEngineGuidelines SearchEngineMarketing SearchEngineOptimization SearchEngineRegistration SearchEngineSpam SearchResult SearchTerm SearchVolume SEOVisibilityFAQ SiteOptimization:Learnhowtoimproveyourwebsite Sitemap.xml SSLEncryption StructuredData T TopicExplorer TopicalRelevance U UniversalSearch URL UserExperience User/SearchIntent UserSignals W WebCatalogues WebDirectory WebPages WebmasterGuidelines Website WebsiteStructure Z ZeroClickSearches