diff --git a/core/src/main/scala/pink/cozydev/protosearch/Field.scala b/core/src/main/scala/pink/cozydev/protosearch/Field.scala
index 8fb2d18..e511680 100644
--- a/core/src/main/scala/pink/cozydev/protosearch/Field.scala
+++ b/core/src/main/scala/pink/cozydev/protosearch/Field.scala
@@ -26,7 +26,7 @@ import pink.cozydev.protosearch.analysis.Analyzer
   * @param indexed Whether the field value should be indexed for fast querying
   * @param positions Whether the positions should be indexed for fast phrase querying
   */
-case class Field(
+final case class Field(
     name: String,
     analyzer: Analyzer,
     stored: Boolean,
diff --git a/core/src/main/scala/pink/cozydev/protosearch/Hit.scala b/core/src/main/scala/pink/cozydev/protosearch/Hit.scala
index ea76714..959be51 100644
--- a/core/src/main/scala/pink/cozydev/protosearch/Hit.scala
+++ b/core/src/main/scala/pink/cozydev/protosearch/Hit.scala
@@ -22,7 +22,7 @@ package pink.cozydev.protosearch
   * @param score The score of this result given the query
   * @param fields Stored fields of the result
   */
-case class Hit(
+final case class Hit(
     val id: Int,
     val score: Double,
     val fields: Map[String, String],
diff --git a/core/src/main/scala/pink/cozydev/protosearch/MultiIndex.scala b/core/src/main/scala/pink/cozydev/protosearch/MultiIndex.scala
index 7d6868c..1acb61b 100644
--- a/core/src/main/scala/pink/cozydev/protosearch/MultiIndex.scala
+++ b/core/src/main/scala/pink/cozydev/protosearch/MultiIndex.scala
@@ -16,7 +16,7 @@
 
 package pink.cozydev.protosearch
 
-case class MultiIndex(
+final case class MultiIndex(
     indexes: Map[String, Index],
     schema: Schema,
     fields: Map[String, Array[String]],
diff --git a/core/src/main/scala/pink/cozydev/protosearch/Scorer.scala b/core/src/main/scala/pink/cozydev/protosearch/Scorer.scala
index 8d3bd00..81b28e0 100644
--- a/core/src/main/scala/pink/cozydev/protosearch/Scorer.scala
+++ b/core/src/main/scala/pink/cozydev/protosearch/Scorer.scala
@@ -24,7 +24,7 @@ import pink.cozydev.protosearch.internal.PositionalIter
 
 import java.util.regex.PatternSyntaxException
 
-case class Scorer(index: MultiIndex, defaultOR: Boolean = true) {
+final case class Scorer(index: MultiIndex, defaultOR: Boolean = true) {
 
   private val defaultIdx: Index = index.indexes(index.schema.defaultField)
 
diff --git a/core/src/main/scala/pink/cozydev/protosearch/analysis/QueryAnalyzer.scala b/core/src/main/scala/pink/cozydev/protosearch/analysis/QueryAnalyzer.scala
index 175e9d0..07e32cf 100644
--- a/core/src/main/scala/pink/cozydev/protosearch/analysis/QueryAnalyzer.scala
+++ b/core/src/main/scala/pink/cozydev/protosearch/analysis/QueryAnalyzer.scala
@@ -23,7 +23,7 @@ import pink.cozydev.lucille.QueryParser
 // TODO This is a hack, the Lucille parser tokenizes on white space only currently
 // We perhaps want Lucille to use a tokenizer from textmogrify
 // In the meantime, we rewrite the Query with our `Analyzer`
-case class QueryAnalyzer(
+final case class QueryAnalyzer(
     defaultField: String,
     analyzers: Map[String, Analyzer],
 ) {