diff --git a/kotlin-native/tools/benchmarksAnalyzer/build.gradle b/kotlin-native/tools/benchmarksAnalyzer/build.gradle
index dc9507a985d..1872fc8632b 100644
--- a/kotlin-native/tools/benchmarksAnalyzer/build.gradle
+++ b/kotlin-native/tools/benchmarksAnalyzer/build.gradle
@@ -156,7 +156,7 @@ kotlin {
                 }
             }
         }
-        fromPreset(presets.js, 'js') {
+        fromPreset(presets.jsIr, 'js') {
             compilations.main.kotlinOptions {
                 main = "noCall"
             }
@@ -184,7 +184,7 @@ kotlin {
         }
     }
 
-    js {
+    js(IR) {
         browser {
             distribution {
                 directory = new File("$projectDir/web/")
diff --git a/kotlin-native/tools/performance-server/shared/src/main/kotlin/org/jetbrains/elastic/ElasticSearchIndex.kt b/kotlin-native/tools/performance-server/shared/src/main/kotlin/org/jetbrains/elastic/ElasticSearchIndex.kt
index 216cf04c37a..dd930c2ee90 100644
--- a/kotlin-native/tools/performance-server/shared/src/main/kotlin/org/jetbrains/elastic/ElasticSearchIndex.kt
+++ b/kotlin-native/tools/performance-server/shared/src/main/kotlin/org/jetbrains/elastic/ElasticSearchIndex.kt
@@ -119,7 +119,7 @@ data class BuildInfo(val buildNumber: String, val startTime: String, val endTime
                 val buildTypeElement = data.getOptionalField("buildType")
                 val buildType = buildTypeElement?.let {
                     elementToString(buildTypeElement, "buildType")
-                } ?: null
+                }
                 return BuildInfo(buildNumber, startTime, endTime, CommitsList(commits), branch, agentInfo, buildType)
             } else {
                 error("Top level entity is expected to be an object. Please, check origin files.")
@@ -161,7 +161,7 @@ abstract class ElasticSearchIndex(val indexName: String, val connector: ElasticS
                 "mappings": {
                 "properties": {
                     ${mapping.map { (property, type) ->
-                        "\"${property}\": { \"type\": \"${type.name.toLowerCase()}\"${if (type == ElasticSearchType.DATE) "," +
+                        "\"${property}\": { \"type\": \"${type.name.lowercase()}\"${if (type == ElasticSearchType.DATE) "," +
                     "\"format\": \"basic_date_time_no_millis\"" else ""} }"
                     }.joinToString()}}
                 }
diff --git a/kotlin-native/tools/performance-server/src/main/kotlin/database/BenchmarksIndexesDispatcher.kt b/kotlin-native/tools/performance-server/src/main/kotlin/database/BenchmarksIndexesDispatcher.kt
index 5d445c29b17..72752709348 100644
--- a/kotlin-native/tools/performance-server/src/main/kotlin/database/BenchmarksIndexesDispatcher.kt
+++ b/kotlin-native/tools/performance-server/src/main/kotlin/database/BenchmarksIndexesDispatcher.kt
@@ -27,7 +27,7 @@ class BenchmarksIndexesDispatcher(connector: ElasticSearchConnector, val feature
     // Becnhmarks indexes to work with in case of existing feature values.
     private val benchmarksIndexes =
             if (featureValues.isNotEmpty())
-                featureValues.map { it to BenchmarksIndex("benchmarks_${it.replace(" ", "_").toLowerCase()}", connector) }
+                featureValues.map { it to BenchmarksIndex("benchmarks_${it.replace(" ", "_").lowercase()}", connector) }
                         .toMap()
             else emptyMap()
 
@@ -122,7 +122,7 @@ class BenchmarksIndexesDispatcher(connector: ElasticSearchConnector, val feature
                                     "bool": {
                                         "must": [
                                             { "match": { "benchmarks.metric": "$metricName" } },
-                                            { "terms": { "benchmarks.name": [${samples.map { "\"${it.toLowerCase()}\"" }.joinToString()}] }}
+                                            { "terms": { "benchmarks.name": [${samples.map { "\"${it.lowercase()}\"" }.joinToString()}] }}
                                         ]
                                     }  
                                 }, "inner_hits": {
diff --git a/kotlin-native/tools/performance-server/src/main/kotlin/database/DatabaseRequests.kt b/kotlin-native/tools/performance-server/src/main/kotlin/database/DatabaseRequests.kt
index dbac550f8fd..ef44ae6101d 100644
--- a/kotlin-native/tools/performance-server/src/main/kotlin/database/DatabaseRequests.kt
+++ b/kotlin-native/tools/performance-server/src/main/kotlin/database/DatabaseRequests.kt
@@ -50,7 +50,7 @@ internal fun getBuildsDescription(type: String?, branch: String?, agentInfo: Str
                                      { "regexp": { "buildNumber": { "value": "${if (it == "release")  
                                         ".*eap.*|.*release.*|.*rc.*" else ".*dev.*"}" } } 
                                      },
-                                     { "match": { "buildType": "${it.toUpperCase()}" } }
+                                     { "match": { "buildType": "${it.uppercase()}" } }
                                  ]
                             }},
                             { "bool": {
diff --git a/kotlin-native/tools/performance-server/src/main/kotlin/main.kt b/kotlin-native/tools/performance-server/src/main/kotlin/main.kt
index 8c76e121db7..6f7cbe0447c 100644
--- a/kotlin-native/tools/performance-server/src/main/kotlin/main.kt
+++ b/kotlin-native/tools/performance-server/src/main/kotlin/main.kt
@@ -10,7 +10,7 @@ external fun require(module: String): dynamic
 external val process: dynamic
 external val __dirname: dynamic
 
-fun main(args: Array<String>) {
+fun main() {
     println("Server Starting!")
 
     val express = require("express")
@@ -28,7 +28,7 @@ fun main(args: Array<String>) {
     app.set("view engine", "ejs")
     app.use(express.static("ui"))
 
-    val server = http.createServer(app)
+    http.createServer(app)
     app.listen(port, {
         println("App listening on port " + port + "!")
     })
diff --git a/kotlin-native/tools/performance-server/src/main/kotlin/network/CachableResponseDispatcher.kt b/kotlin-native/tools/performance-server/src/main/kotlin/network/CachableResponseDispatcher.kt
index f685d9f08cc..bb24fdaf7fd 100644
--- a/kotlin-native/tools/performance-server/src/main/kotlin/network/CachableResponseDispatcher.kt
+++ b/kotlin-native/tools/performance-server/src/main/kotlin/network/CachableResponseDispatcher.kt
@@ -24,7 +24,7 @@ object CachableResponseDispatcher {
                     action: (success: (result: Any) -> Unit, reject: () -> Unit) -> Unit) {
         cachedResponses[request.url]?.let {
             // Update cache value if needed. Update only if last result was get later than 2 minutes.
-            if (it.time.elapsedNow().inMinutes > 2.0) {
+            if (it.time.elapsedNow().inWholeMinutes >= 2.0) {
                 println("Cache update for ${request.url}...")
                 action({ result: Any ->
                     cachedResponses[request.url] = CachedResponse(result, TimeSource.Monotonic.markNow())
diff --git a/kotlin-native/tools/performance-server/src/main/kotlin/routes/route.kt b/kotlin-native/tools/performance-server/src/main/kotlin/routes/route.kt
index c01283e66c0..1fcc49e7caa 100644
--- a/kotlin-native/tools/performance-server/src/main/kotlin/routes/route.kt
+++ b/kotlin-native/tools/performance-server/src/main/kotlin/routes/route.kt
@@ -45,6 +45,7 @@ internal fun convertToNewFormat(data: JsonObject): List<Any> {
 }
 
 // Convert data results to expected format.
+@Suppress("UNCHECKED_CAST")
 internal fun convert(json: String, buildNumber: String, target: String): List<BenchmarksReport> {
     val data = JsonTreeParser.parse(json)
     val reports = if (data is JsonArray) {
@@ -143,12 +144,12 @@ data class BuildRegister(val buildId: String, val teamCityUser: String, val team
             val data = JsonTreeParser.parse(response).jsonObject
             data.getArray("build").forEach {
                 (it as JsonObject).getObject("revisions").getArray("revision").forEach {
-                    val currentBranch = (it as JsonObject).getPrimitive("vcsBranchName").content.removePrefix("refs/heads/")
-                    val currentProject = (it as JsonObject).getObject("vcs-root-instance").getPrimitive("name").content
+                    it as JsonObject
+                    val currentBranch = it.getPrimitive("vcsBranchName").content.removePrefix("refs/heads/")
+                    val currentProject = it.getObject("vcs-root-instance").getPrimitive("name").content
                     if (projects.anyMatches(currentProject)) {
                         branch = currentBranch
                     }
-                    return@forEach
                 }
             }
             branch ?: error("No project from list $projects can be found in build $buildId")
@@ -476,7 +477,7 @@ fun router(networkConnector: NetworkConnector) {
             distinctValues("branch", buildInfoIndex).then { results ->
                 success(results)
             }.catch { errorMessage ->
-                error(errorMessage.message ?: "Failed getting branches list.")
+                println(errorMessage.message ?: "Failed getting branches list.")
                 reject()
             }
         }
diff --git a/kotlin-native/tools/performance-server/ui/build.gradle b/kotlin-native/tools/performance-server/ui/build.gradle
index f6fbdc586a4..cf66304a60c 100644
--- a/kotlin-native/tools/performance-server/ui/build.gradle
+++ b/kotlin-native/tools/performance-server/ui/build.gradle
@@ -51,7 +51,7 @@ repositories {
 apply plugin: 'kotlin-multiplatform'
 
 kotlin {
-    js {
+    js(IR) {
         browser {
             binaries.executable()
             distribution {
diff --git a/kotlin-native/tools/performance-server/ui/src/main/kotlin/main.kt b/kotlin-native/tools/performance-server/ui/src/main/kotlin/main.kt
index d8bf70657f4..02a4a97822d 100644
--- a/kotlin-native/tools/performance-server/ui/src/main/kotlin/main.kt
+++ b/kotlin-native/tools/performance-server/ui/src/main/kotlin/main.kt
@@ -103,8 +103,7 @@ fun customizeChart(chart: dynamic, chartContainer: String, jquerySelector: dynam
         var element = data.element
         if (data.type == "point") {
             val pointSize = 12
-            val currentBuild = builds.get(data.index)
-            currentBuild?.let { currentBuild ->
+            builds.get(data.index)?.let { currentBuild ->
                 // Higlight builds with failures.
                 if (currentBuild.failuresNumber > 0) {
                     val svgParameters: dynamic = object {}
@@ -148,9 +147,10 @@ fun customizeChart(chart: dynamic, chartContainer: String, jquerySelector: dynam
                     append("time: ${currentBuild.formattedStartTime}-${currentBuild.formattedFinishTime}<br>")
                     append("Commits:<br>")
                     val commitsList = (JsonTreeParser.parse("{${currentBuild.commits}}") as JsonObject).getArray("commits").map {
+                        it as JsonObject
                         Commit(
-                                (it as JsonObject).getPrimitive("revision").content,
-                                (it as JsonObject).getPrimitive("developer").content
+                                it.getPrimitive("revision").content,
+                                it.getPrimitive("developer").content
                         )
                     }
                     val commits = if (commitsList.size > 3) commitsList.slice(0..2) else commitsList
@@ -171,11 +171,11 @@ fun customizeChart(chart: dynamic, chartContainer: String, jquerySelector: dynam
     })
     chart.on("created", {
         val currentChart = jquerySelector
-        val parameters: dynamic = object {}
-        parameters["selector"] = "[data-chart-tooltip=\"$chartContainer\"]"
-        parameters["container"] = "#$chartContainer"
-        parameters["html"] = true
-        currentChart.tooltip(parameters)
+        val chartParameters: dynamic = object {}
+        chartParameters["selector"] = "[data-chart-tooltip=\"$chartContainer\"]"
+        chartParameters["container"] = "#$chartContainer"
+        chartParameters["html"] = true
+        currentChart.tooltip(chartParameters)
     })
 }
 
@@ -189,7 +189,7 @@ external fun encodeURIComponent(url: String): String
 fun getDatesComponents() = "${beforeDate?.let {"&before=${encodeURIComponent(it)}"} ?: ""}" +
         "${afterDate?.let {"&after=${encodeURIComponent(it)}"} ?: ""}"
 
-fun main(args: Array<String>) {
+fun main() {
     val serverUrl = window.location.origin // use "http://localhost:3000" for local debug.
     val zoomRatio = 2
 
@@ -216,6 +216,7 @@ fun main(args: Array<String>) {
         // Add release branches to selector.
         branches.filter { it != "master" }.forEach {
             if ("^v?(\\d|\\.)+(-M\\d)?(-fixes)?$".toRegex().matches(it)) {
+                @Suppress("UNUSED_VARIABLE") // it's used within js block
                 val option = Option(it, it)
                 js("$('#inputGroupBranch')").append(js("$(option)"))
             }
@@ -310,8 +311,7 @@ fun main(args: Array<String>) {
 
     val metricUrl = "$serverUrl/metricValue/${parameters["target"]}/"
 
-    val unstableBenchmarksPromise = sendGetRequest("$serverUrl/unstable").then { response ->
-        val unstableList = response as String
+    val unstableBenchmarksPromise = sendGetRequest("$serverUrl/unstable").then { unstableList ->
         val data = JsonTreeParser.parse(unstableList)
         if (data !is JsonArray) {
             error("Response is expected to be an array.")
@@ -322,15 +322,13 @@ fun main(args: Array<String>) {
     }
 
     // Get builds description.
-    val buildsInfoPromise = sendGetRequest(descriptionUrl).then { response ->
-        val buildsInfo = response as String
+    val buildsInfoPromise = sendGetRequest(descriptionUrl).then { buildsInfo ->
         val data = JsonTreeParser.parse(buildsInfo)
         if (data !is JsonArray) {
             error("Response is expected to be an array.")
         }
         data.jsonArray.map {
-            val element = it as JsonElement
-            if (element.isNull) null else Build.create(element as JsonObject)
+            if (it.isNull) null else Build.create(it as JsonObject)
         }
     }
 
@@ -405,12 +403,12 @@ fun main(args: Array<String>) {
                 else ""
 
                 val requestedMetric = if (metric.startsWith("EXECUTION_TIME")) "EXECUTION_TIME" else metric
-                val url = "$metricUrl$requestedMetric$getParameters$branchParameter${
+                val queryUrl = "$metricUrl$requestedMetric$getParameters$branchParameter${
                     if (parameters["type"] != "all")
                         (if (getParameters.isEmpty() && branchParameter.isEmpty()) "?" else "&") + "type=${parameters["type"]}"
                     else ""
                 }&count=$buildsNumberToShow${getDatesComponents()}"
-                sendGetRequest(url)
+                sendGetRequest(queryUrl)
             }.toTypedArray()
 
             // Get metrics values for charts.
@@ -422,8 +420,7 @@ fun main(args: Array<String>) {
                     }
 
                     val labels = results.map { it.first }
-                    val values = results[0]?.second?.size?.let { (0..it - 1).map { i -> results.map { it.second[i] } } }
-                            ?: emptyList()
+                    val values = results[0].second.size.let { (0..it - 1).map { i -> results.map { it.second[i] } } }
                     labels to values
                 }
                 val labels = valuesList[0].first
@@ -436,7 +433,7 @@ fun main(args: Array<String>) {
                         compileData = labels to values.map { it.map { it?.let { it / 1000 } } }
                         compileChart = Chartist.Line("#compile_chart",
                                 getChartData(labels, compileData.second),
-                                getChartOptions(valuesToShow["COMPILE_TIME"]!![0]!!["samples"]!!.split(',').toTypedArray(),
+                                getChartOptions(valuesToShow["COMPILE_TIME"]!![0]["samples"]!!.split(',').toTypedArray(),
                                         "Time, milliseconds"))
                         buildsInfoPromise.then { builds ->
                             customizeChart(compileChart, "compile_chart", js("$(\"#compile_chart\")"), builds, parameters)