diff --git a/src/main/kotlin/com/featurevisor/sdk/DatafileReader.kt b/src/main/kotlin/com/featurevisor/sdk/DatafileReader.kt
index eef4c77..b39d6bd 100644
--- a/src/main/kotlin/com/featurevisor/sdk/DatafileReader.kt
+++ b/src/main/kotlin/com/featurevisor/sdk/DatafileReader.kt
@@ -9,14 +9,14 @@ import com.featurevisor.types.Segment
 import com.featurevisor.types.SegmentKey
 
 class DatafileReader constructor(
-    datafileJson: DatafileContent,
+    datafileContent: DatafileContent,
 ) {
 
-    private val schemaVersion: String = datafileJson.schemaVersion
-    private val revision: String = datafileJson.revision
-    private val attributes: List<Attribute> = datafileJson.attributes
-    private val segments: List<Segment> = datafileJson.segments
-    private val features: List<Feature> = datafileJson.features
+    private val schemaVersion: String = datafileContent.schemaVersion
+    private val revision: String = datafileContent.revision
+    private val attributes: Map<AttributeKey, Attribute> = datafileContent.attributes.associateBy { it.key }
+    private val segments: Map<SegmentKey, Segment> = datafileContent.segments.associateBy { it.key }
+    private val features: Map<FeatureKey, Feature> = datafileContent.features.associateBy { it.key }
 
     fun getRevision(): String {
         return revision
@@ -27,18 +27,18 @@ class DatafileReader constructor(
     }
 
     fun getAllAttributes(): List<Attribute> {
-        return attributes
+        return attributes.values.toList()
     }
 
     fun getAttribute(attributeKey: AttributeKey): Attribute? {
-        return attributes.find { attribute -> attribute.key == attributeKey }
+        return attributes[attributeKey]
     }
 
     fun getSegment(segmentKey: SegmentKey): Segment? {
-        return segments.find { segment -> segment.key == segmentKey }
+        return segments[segmentKey]
     }
 
     fun getFeature(featureKey: FeatureKey): Feature? {
-        return features.find { feature -> feature.key == featureKey }
+        return features[featureKey]
     }
 }
diff --git a/src/main/kotlin/com/featurevisor/sdk/Instance.kt b/src/main/kotlin/com/featurevisor/sdk/Instance.kt
index d833849..af7ff2a 100644
--- a/src/main/kotlin/com/featurevisor/sdk/Instance.kt
+++ b/src/main/kotlin/com/featurevisor/sdk/Instance.kt
@@ -126,14 +126,14 @@ class FeaturevisorInstance private constructor(options: InstanceOptions) {
         val data = datafileJSON.toByteArray(Charsets.UTF_8)
         try {
             val datafileContent = Json.decodeFromString<DatafileContent>(String(data))
-            datafileReader = DatafileReader(datafileJson = datafileContent)
+            datafileReader = DatafileReader(datafileContent = datafileContent)
         } catch (e: Exception) {
             logger?.error("could not parse datafile", mapOf("error" to e))
         }
     }
 
     fun setDatafile(datafileContent: DatafileContent) {
-        datafileReader = DatafileReader(datafileJson = datafileContent)
+        datafileReader = DatafileReader(datafileContent = datafileContent)
     }
 
     fun setStickyFeatures(stickyFeatures: StickyFeatures?) {
diff --git a/src/test/kotlin/com/featurevisor/sdk/DatafileReaderTest.kt b/src/test/kotlin/com/featurevisor/sdk/DatafileReaderTest.kt
index 9a146e0..3882266 100644
--- a/src/test/kotlin/com/featurevisor/sdk/DatafileReaderTest.kt
+++ b/src/test/kotlin/com/featurevisor/sdk/DatafileReaderTest.kt
@@ -7,7 +7,7 @@ import org.junit.jupiter.api.Test
 class DatafileReaderTest {
 
     private val systemUnderTest = DatafileReader(
-        datafileJson = DatafileContentFactory.get()
+        datafileContent = DatafileContentFactory.get()
     )
 
     @Test