diff --git a/core/src/main/scala/ai/h2o/sparkling/frame/H2OColumn.scala b/core/src/main/scala/ai/h2o/sparkling/H2OColumn.scala
similarity index 97%
rename from core/src/main/scala/ai/h2o/sparkling/frame/H2OColumn.scala
rename to core/src/main/scala/ai/h2o/sparkling/H2OColumn.scala
index bb66e5c59c..0e03c13fa1 100644
--- a/core/src/main/scala/ai/h2o/sparkling/frame/H2OColumn.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/H2OColumn.scala
@@ -15,7 +15,7 @@
 * limitations under the License.
 */
 
-package ai.h2o.sparkling.frame
+package ai.h2o.sparkling
 
 case class H2OColumn(
                       name: String,
diff --git a/core/src/main/scala/ai/h2o/sparkling/frame/H2OColumnType.scala b/core/src/main/scala/ai/h2o/sparkling/H2OColumnType.scala
similarity index 97%
rename from core/src/main/scala/ai/h2o/sparkling/frame/H2OColumnType.scala
rename to core/src/main/scala/ai/h2o/sparkling/H2OColumnType.scala
index b3669a05e2..f72198d5d4 100644
--- a/core/src/main/scala/ai/h2o/sparkling/frame/H2OColumnType.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/H2OColumnType.scala
@@ -15,7 +15,7 @@
 * limitations under the License.
 */
 
-package ai.h2o.sparkling.frame
+package ai.h2o.sparkling
 
 object H2OColumnType extends Enumeration {
   val enum, string, int, real, time, uuid = Value
diff --git a/core/src/main/scala/ai/h2o/sparkling/frame/H2OFrame.scala b/core/src/main/scala/ai/h2o/sparkling/H2OFrame.scala
similarity index 97%
rename from core/src/main/scala/ai/h2o/sparkling/frame/H2OFrame.scala
rename to core/src/main/scala/ai/h2o/sparkling/H2OFrame.scala
index 2cd6b15d07..fb3e32e997 100644
--- a/core/src/main/scala/ai/h2o/sparkling/frame/H2OFrame.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/H2OFrame.scala
@@ -15,16 +15,15 @@
 * limitations under the License.
 */
 
-package ai.h2o.sparkling.frame
+package ai.h2o.sparkling
 
 import java.text.MessageFormat
 
-import ai.h2o.sparkling.backend.NodeDesc
 import ai.h2o.sparkling.backend.utils.RestApiUtils._
 import ai.h2o.sparkling.backend.utils.{RestCommunication, RestEncodingUtils}
+import ai.h2o.sparkling.backend.{H2OChunk, H2OJob, NodeDesc}
 import ai.h2o.sparkling.extensions.rest.api.Paths
 import ai.h2o.sparkling.extensions.rest.api.schema.{FinalizeFrameV3, InitializeFrameV3}
-import ai.h2o.sparkling.job.H2OJob
 import ai.h2o.sparkling.utils.Base64Encoding
 import org.apache.spark.h2o.{H2OConf, H2OContext}
 import water.api.schemas3.FrameChunksV3.FrameChunkV3
@@ -34,7 +33,7 @@ import water.api.schemas3._
 /**
  * H2OFrame representation via Rest API
  */
-class H2OFrame private(val frameId: String, val columns: Array[H2OColumn], val chunks: Array[H2OChunk])
+class H2OFrame private(val frameId: String, val columns: Array[H2OColumn], private[sparkling] val chunks: Array[H2OChunk])
   extends Serializable with RestEncodingUtils {
   private val conf = H2OContext.ensure("H2OContext needs to be running in order to create H2OFrame").getConf
   val columnNames: Array[String] = columns.map(_.name)
diff --git a/core/src/main/scala/ai/h2o/sparkling/frame/H2OChunk.scala b/core/src/main/scala/ai/h2o/sparkling/backend/H2OChunk.scala
similarity index 94%
rename from core/src/main/scala/ai/h2o/sparkling/frame/H2OChunk.scala
rename to core/src/main/scala/ai/h2o/sparkling/backend/H2OChunk.scala
index 994b4bd170..8583372860 100644
--- a/core/src/main/scala/ai/h2o/sparkling/frame/H2OChunk.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/backend/H2OChunk.scala
@@ -15,20 +15,19 @@
 * limitations under the License.
 */
 
-package ai.h2o.sparkling.frame
+package ai.h2o.sparkling.backend
 
 import java.io.{InputStream, OutputStream}
 
-import ai.h2o.sparkling.backend.NodeDesc
 import ai.h2o.sparkling.backend.utils.{RestApiUtils, RestCommunication}
 import ai.h2o.sparkling.extensions.rest.api.Paths
 import ai.h2o.sparkling.utils.{Base64Encoding, Compression}
 import org.apache.spark.h2o.H2OConf
 
 
-case class H2OChunk(index: Int, numberOfRows: Int, location: NodeDesc)
+private[sparkling] case class H2OChunk(index: Int, numberOfRows: Int, location: NodeDesc)
 
-object H2OChunk extends RestCommunication {
+private[sparkling] object H2OChunk extends RestCommunication {
   def getChunkAsInputStream(
                              node: NodeDesc,
                              conf: H2OConf,
diff --git a/core/src/main/scala/ai/h2o/sparkling/backend/H2ODataFrame.scala b/core/src/main/scala/ai/h2o/sparkling/backend/H2ODataFrame.scala
index fe418e3a18..289687e8c5 100644
--- a/core/src/main/scala/ai/h2o/sparkling/backend/H2ODataFrame.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/backend/H2ODataFrame.scala
@@ -17,10 +17,9 @@
 
 package ai.h2o.sparkling.backend
 
-import ai.h2o.sparkling.SparkTimeZone
 import ai.h2o.sparkling.backend.utils.SupportedTypes._
 import ai.h2o.sparkling.backend.utils.{ConversionUtils, ReflectionUtils}
-import ai.h2o.sparkling.frame.H2OFrame
+import ai.h2o.sparkling.{H2OFrame, SparkTimeZone}
 import org.apache.spark.h2o.H2OContext
 import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.types.DataType
diff --git a/core/src/main/scala/ai/h2o/sparkling/backend/H2OFrameRelation.scala b/core/src/main/scala/ai/h2o/sparkling/backend/H2OFrameRelation.scala
index 9ba4a77036..a426c80757 100644
--- a/core/src/main/scala/ai/h2o/sparkling/backend/H2OFrameRelation.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/backend/H2OFrameRelation.scala
@@ -18,7 +18,7 @@
 package ai.h2o.sparkling.backend
 
 import ai.h2o.sparkling.backend.utils.ReflectionUtils
-import ai.h2o.sparkling.frame.{H2OColumn, H2OColumnType, H2OFrame}
+import ai.h2o.sparkling.{H2OColumn, H2OColumnType, H2OFrame}
 import org.apache.spark.h2o.H2OContext
 import org.apache.spark.rdd.RDD
 import org.apache.spark.sql.sources.{BaseRelation, PrunedScan, TableScan}
diff --git a/core/src/main/scala/ai/h2o/sparkling/job/H2OJob.scala b/core/src/main/scala/ai/h2o/sparkling/backend/H2OJob.scala
similarity index 93%
rename from core/src/main/scala/ai/h2o/sparkling/job/H2OJob.scala
rename to core/src/main/scala/ai/h2o/sparkling/backend/H2OJob.scala
index fda1700592..f1e933c3f5 100644
--- a/core/src/main/scala/ai/h2o/sparkling/job/H2OJob.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/backend/H2OJob.scala
@@ -15,7 +15,7 @@
 * limitations under the License.
 */
 
-package ai.h2o.sparkling.job
+package ai.h2o.sparkling.backend
 
 import ai.h2o.sparkling.backend.utils.RestApiUtils.getClusterEndpoint
 import ai.h2o.sparkling.backend.utils.RestCommunication
@@ -23,7 +23,7 @@ import org.apache.spark.expose.Logging
 import org.apache.spark.h2o.{H2OConf, H2OContext}
 import water.api.schemas3.{JobV3, JobsV3}
 
-class H2OJob private(val id: String) extends Logging {
+private[sparkling] class H2OJob private(val id: String) extends Logging {
   private val conf = H2OContext.ensure("H2OContext needs to be running!").getConf
 
   private def fetchStatus(): H2OJobStatus.Value = {
@@ -48,7 +48,7 @@ class H2OJob private(val id: String) extends Logging {
   }
 }
 
-object H2OJob extends RestCommunication {
+private[sparkling] object H2OJob extends RestCommunication {
   def apply(jobId: String): H2OJob = {
     val conf = H2OContext.ensure().getConf
     verifyAndGetJob(conf, jobId)
diff --git a/core/src/main/scala/ai/h2o/sparkling/job/H2OJobStatus.scala b/core/src/main/scala/ai/h2o/sparkling/backend/H2OJobStatus.scala
similarity index 96%
rename from core/src/main/scala/ai/h2o/sparkling/job/H2OJobStatus.scala
rename to core/src/main/scala/ai/h2o/sparkling/backend/H2OJobStatus.scala
index d610c12dfb..6953d889db 100644
--- a/core/src/main/scala/ai/h2o/sparkling/job/H2OJobStatus.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/backend/H2OJobStatus.scala
@@ -15,7 +15,7 @@
 * limitations under the License.
 */
 
-package ai.h2o.sparkling.job
+package ai.h2o.sparkling.backend
 
 object H2OJobStatus extends Enumeration {
   val DONE, CANCELLED, FAILED, RUNNING = Value
diff --git a/core/src/main/scala/ai/h2o/sparkling/backend/H2ORDD.scala b/core/src/main/scala/ai/h2o/sparkling/backend/H2ORDD.scala
index 45d83b542c..31bdec02fc 100644
--- a/core/src/main/scala/ai/h2o/sparkling/backend/H2ORDD.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/backend/H2ORDD.scala
@@ -19,9 +19,8 @@ package ai.h2o.sparkling.backend
 
 import java.lang.reflect.Constructor
 
-import ai.h2o.sparkling.SparkTimeZone
 import ai.h2o.sparkling.backend.utils.{ConversionUtils, ProductType}
-import ai.h2o.sparkling.frame.H2OFrame
+import ai.h2o.sparkling.{H2OFrame, SparkTimeZone}
 import org.apache.spark.h2o.H2OContext
 import org.apache.spark.{Partition, TaskContext}
 
diff --git a/core/src/main/scala/ai/h2o/sparkling/backend/H2OSparkEntity.scala b/core/src/main/scala/ai/h2o/sparkling/backend/H2OSparkEntity.scala
index 803f319f92..b71fe02b63 100644
--- a/core/src/main/scala/ai/h2o/sparkling/backend/H2OSparkEntity.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/backend/H2OSparkEntity.scala
@@ -17,7 +17,7 @@
 
 package ai.h2o.sparkling.backend
 
-import ai.h2o.sparkling.frame.H2OFrame
+import ai.h2o.sparkling.H2OFrame
 import org.apache.spark.Partition
 
 /**
diff --git a/core/src/main/scala/ai/h2o/sparkling/backend/Reader.scala b/core/src/main/scala/ai/h2o/sparkling/backend/Reader.scala
index cc03deaae0..3c5234d56c 100644
--- a/core/src/main/scala/ai/h2o/sparkling/backend/Reader.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/backend/Reader.scala
@@ -23,7 +23,6 @@ import ai.h2o.sparkling.backend.converters.TimeZoneConversions
 import ai.h2o.sparkling.backend.utils.SupportedTypes
 import ai.h2o.sparkling.backend.utils.SupportedTypes._
 import ai.h2o.sparkling.extensions.serde.ChunkAutoBufferReader
-import ai.h2o.sparkling.frame.H2OChunk
 import org.apache.spark.h2o.H2OConf
 import org.apache.spark.unsafe.types.UTF8String
 
diff --git a/core/src/main/scala/ai/h2o/sparkling/backend/Writer.scala b/core/src/main/scala/ai/h2o/sparkling/backend/Writer.scala
index d2d6354596..97219b3680 100644
--- a/core/src/main/scala/ai/h2o/sparkling/backend/Writer.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/backend/Writer.scala
@@ -20,9 +20,9 @@ package ai.h2o.sparkling.backend
 import java.io.Closeable
 import java.util.TimeZone
 
+import ai.h2o.sparkling.H2OFrame
 import ai.h2o.sparkling.backend.converters.TimeZoneConverter
 import ai.h2o.sparkling.extensions.serde.{ChunkAutoBufferWriter, SerdeUtils}
-import ai.h2o.sparkling.frame.{H2OChunk, H2OFrame}
 import ai.h2o.sparkling.utils.ScalaUtils.withResource
 import ai.h2o.sparkling.utils.SparkSessionUtils
 import org.apache.spark.h2o.{H2OContext, RDD}
diff --git a/core/src/main/scala/ai/h2o/sparkling/backend/converters/SparkDataFrameConverter.scala b/core/src/main/scala/ai/h2o/sparkling/backend/converters/SparkDataFrameConverter.scala
index e49346641e..701c12a885 100644
--- a/core/src/main/scala/ai/h2o/sparkling/backend/converters/SparkDataFrameConverter.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/backend/converters/SparkDataFrameConverter.scala
@@ -47,7 +47,7 @@ object SparkDataFrameConverter extends Logging {
 
   def toDataFrame[T <: Frame](hc: H2OContext, fr: T, copyMetadata: Boolean): DataFrame = {
     DKV.put(fr)
-    toDataFrame(hc, ai.h2o.sparkling.frame.H2OFrame(fr._key.toString), copyMetadata)
+    toDataFrame(hc, ai.h2o.sparkling.H2OFrame(fr._key.toString), copyMetadata)
   }
 
   /**
@@ -59,7 +59,7 @@ object SparkDataFrameConverter extends Logging {
    * @return a new DataFrame definition using given H2OFrame as data source
    */
 
-  def toDataFrame(hc: H2OContext, fr: ai.h2o.sparkling.frame.H2OFrame, copyMetadata: Boolean): DataFrame = {
+  def toDataFrame(hc: H2OContext, fr: ai.h2o.sparkling.H2OFrame, copyMetadata: Boolean): DataFrame = {
     val spark = SparkSessionUtils.active
     val relation = H2OFrameRelation(fr, copyMetadata)(spark.sqlContext)
     spark.baseRelationToDataFrame(relation)
diff --git a/core/src/main/scala/ai/h2o/sparkling/backend/converters/SupportedRDDConverter.scala b/core/src/main/scala/ai/h2o/sparkling/backend/converters/SupportedRDDConverter.scala
index f2642ef7d1..495a6f4bcd 100644
--- a/core/src/main/scala/ai/h2o/sparkling/backend/converters/SupportedRDDConverter.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/backend/converters/SupportedRDDConverter.scala
@@ -43,11 +43,11 @@ object SupportedRDDConverter {
   /** Transform H2OFrame to RDD */
   def toRDD[A <: Product : TypeTag : ClassTag, T <: Frame](hc: H2OContext, fr: T): RDD[A] = {
     DKV.put(fr)
-    toRDD(hc, ai.h2o.sparkling.frame.H2OFrame(fr._key.toString))
+    toRDD(hc, ai.h2o.sparkling.H2OFrame(fr._key.toString))
   }
 
   /** Transform H2OFrame to RDD */
-  def toRDD[A <: Product : TypeTag : ClassTag](hc: H2OContext, fr: ai.h2o.sparkling.frame.H2OFrame): RDD[A] = {
+  def toRDD[A <: Product : TypeTag : ClassTag](hc: H2OContext, fr: ai.h2o.sparkling.H2OFrame): RDD[A] = {
     new H2ORDD[A](fr)(hc)
   }
 }
diff --git a/core/src/main/scala/ai/h2o/sparkling/backend/utils/ReflectionUtils.scala b/core/src/main/scala/ai/h2o/sparkling/backend/utils/ReflectionUtils.scala
index 7fe6a1b669..5675b1668d 100644
--- a/core/src/main/scala/ai/h2o/sparkling/backend/utils/ReflectionUtils.scala
+++ b/core/src/main/scala/ai/h2o/sparkling/backend/utils/ReflectionUtils.scala
@@ -18,7 +18,7 @@
 package ai.h2o.sparkling.backend.utils
 
 import ai.h2o.sparkling.backend.utils.SupportedTypes._
-import ai.h2o.sparkling.frame.{H2OColumn, H2OColumnType}
+import ai.h2o.sparkling.{H2OColumn, H2OColumnType}
 import org.apache.spark.sql.types._
 import water.api.API
 import water.fvec.Vec
diff --git a/core/src/main/scala/org/apache/spark/h2o/DefaultSource.scala b/core/src/main/scala/org/apache/spark/h2o/DefaultSource.scala
index 95c24d7761..cc9cc6dd1c 100644
--- a/core/src/main/scala/org/apache/spark/h2o/DefaultSource.scala
+++ b/core/src/main/scala/org/apache/spark/h2o/DefaultSource.scala
@@ -62,7 +62,7 @@ class DefaultSource extends RelationProvider
                               schema: StructType): H2OFrameRelation = {
     val key = checkKey(parameters)
 
-    H2OFrameRelation(ai.h2o.sparkling.frame.H2OFrame(key), copyMetadata = true)(sqlContext)
+    H2OFrameRelation(ai.h2o.sparkling.H2OFrame(key), copyMetadata = true)(sqlContext)
   }
 
   override def createRelation(sqlContext: SQLContext,
diff --git a/core/src/main/scala/org/apache/spark/h2o/H2OContext.scala b/core/src/main/scala/org/apache/spark/h2o/H2OContext.scala
index 47be2f2bdb..832d68c37c 100644
--- a/core/src/main/scala/org/apache/spark/h2o/H2OContext.scala
+++ b/core/src/main/scala/org/apache/spark/h2o/H2OContext.scala
@@ -235,7 +235,7 @@ class H2OContext private(private val conf: H2OConf) extends H2OContextExtensions
     def apply[T <: Frame](fr: T): RDD[A] = SupportedRDDConverter.toRDD[A, T](H2OContext.this, fr)
   }
 
-  def asRDD[A <: Product : TypeTag : ClassTag](fr: ai.h2o.sparkling.frame.H2OFrame): org.apache.spark.rdd.RDD[A] = {
+  def asRDD[A <: Product : TypeTag : ClassTag](fr: ai.h2o.sparkling.H2OFrame): org.apache.spark.rdd.RDD[A] = {
     SupportedRDDConverter.toRDD[A](this, fr)
   }
 
@@ -246,7 +246,7 @@ class H2OContext private(private val conf: H2OConf) extends H2OContextExtensions
   }
 
   def asDataFrame(s: String, copyMetadata: Boolean): DataFrame = {
-    val frame = ai.h2o.sparkling.frame.H2OFrame(s)
+    val frame = ai.h2o.sparkling.H2OFrame(s)
     SparkDataFrameConverter.toDataFrame(this, frame, copyMetadata)
   }
 
diff --git a/core/src/test/scala/ai/h2o/sparkling/frame/H2OFrameTestSuite.scala b/core/src/test/scala/ai/h2o/sparkling/frame/H2OFrameTestSuite.scala
index ea4215bdef..3f9a88fa88 100644
--- a/core/src/test/scala/ai/h2o/sparkling/frame/H2OFrameTestSuite.scala
+++ b/core/src/test/scala/ai/h2o/sparkling/frame/H2OFrameTestSuite.scala
@@ -16,6 +16,7 @@
 */
 package ai.h2o.sparkling.frame
 
+import ai.h2o.sparkling.{H2OColumnType, H2OFrame}
 import org.apache.spark.SparkContext
 import org.apache.spark.h2o.utils.SharedH2OTestContext
 import org.junit.runner.RunWith
diff --git a/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OAlgoCommonUtils.scala b/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OAlgoCommonUtils.scala
index 88c37e3dbc..63312dc42c 100644
--- a/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OAlgoCommonUtils.scala
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OAlgoCommonUtils.scala
@@ -16,7 +16,7 @@
 */
 package ai.h2o.sparkling.ml.algos
 
-import ai.h2o.sparkling.frame.H2OFrame
+import ai.h2o.sparkling.H2OFrame
 import ai.h2o.sparkling.ml.params.H2OCommonParams
 import ai.h2o.sparkling.ml.utils.{EstimatorCommonUtils, SchemaUtils}
 import org.apache.spark.h2o.H2OContext
diff --git a/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OAlgorithm.scala b/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OAlgorithm.scala
index 6f73ea78fe..a2a0c81d01 100644
--- a/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OAlgorithm.scala
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OAlgorithm.scala
@@ -16,12 +16,12 @@
 */
 package ai.h2o.sparkling.ml.algos
 
+import ai.h2o.sparkling.H2OFrame
 import ai.h2o.sparkling.backend.exceptions.RestApiCommunicationException
 import ai.h2o.sparkling.backend.utils.RestCommunication
-import ai.h2o.sparkling.frame.H2OFrame
+import ai.h2o.sparkling.ml.internals.H2OModel
 import ai.h2o.sparkling.ml.models.{H2OMOJOModel, H2OMOJOSettings}
 import ai.h2o.sparkling.ml.params.H2OAlgoCommonParams
-import ai.h2o.sparkling.model.H2OModel
 import hex.Model
 import org.apache.spark.annotation.DeveloperApi
 import org.apache.spark.ml.Estimator
diff --git a/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OAutoML.scala b/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OAutoML.scala
index 5d0b926679..6412818a8f 100644
--- a/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OAutoML.scala
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OAutoML.scala
@@ -16,12 +16,12 @@
 */
 package ai.h2o.sparkling.ml.algos
 
+import ai.h2o.sparkling.H2OFrame
 import ai.h2o.sparkling.backend.utils.{RestApiUtils, RestCommunication}
-import ai.h2o.sparkling.frame.H2OFrame
+import ai.h2o.sparkling.ml.internals.H2OModel
 import ai.h2o.sparkling.ml.models.{H2OMOJOModel, H2OMOJOSettings}
 import ai.h2o.sparkling.ml.params._
 import ai.h2o.sparkling.ml.utils.H2OParamsReadable
-import ai.h2o.sparkling.model.H2OModel
 import ai.h2o.sparkling.utils.ScalaUtils.withResource
 import ai.h2o.sparkling.utils.SparkSessionUtils
 import com.google.gson.{Gson, JsonElement}
diff --git a/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OGridSearch.scala b/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OGridSearch.scala
index 8f39ff6f3a..9032550969 100644
--- a/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OGridSearch.scala
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OGridSearch.scala
@@ -18,13 +18,13 @@ package ai.h2o.sparkling.ml.algos
 
 import java.util
 
+import ai.h2o.sparkling.H2OFrame
 import ai.h2o.sparkling.backend.exceptions.RestApiCommunicationException
 import ai.h2o.sparkling.backend.utils.{RestApiUtils, RestCommunication, RestEncodingUtils}
-import ai.h2o.sparkling.frame.H2OFrame
+import ai.h2o.sparkling.ml.internals.{H2OMetric, H2OModel, H2OModelCategory}
 import ai.h2o.sparkling.ml.models.{H2OMOJOModel, H2OMOJOSettings}
 import ai.h2o.sparkling.ml.params.H2OGridSearchParams
 import ai.h2o.sparkling.ml.utils.H2OParamsReadable
-import ai.h2o.sparkling.model.{H2OMetric, H2OModel, H2OModelCategory}
 import ai.h2o.sparkling.utils.SparkSessionUtils
 import hex.Model
 import hex.grid.HyperSpaceSearchCriteria
diff --git a/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OKMeans.scala b/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OKMeans.scala
index a2da2516b8..5aea96e980 100644
--- a/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OKMeans.scala
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OKMeans.scala
@@ -16,7 +16,7 @@
 */
 package ai.h2o.sparkling.ml.algos
 
-import ai.h2o.sparkling.frame.{H2OColumnType, H2OFrame}
+import ai.h2o.sparkling.{H2OColumnType, H2OFrame}
 import ai.h2o.sparkling.ml.params.H2OKMeansParams
 import hex.kmeans.KMeansModel.KMeansParameters
 import org.apache.spark.ml.util.{DefaultParamsReadable, Identifiable}
diff --git a/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OSupervisedAlgorithm.scala b/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OSupervisedAlgorithm.scala
index b70c74e5a2..0eab1dadbd 100644
--- a/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OSupervisedAlgorithm.scala
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/algos/H2OSupervisedAlgorithm.scala
@@ -16,7 +16,7 @@
 */
 package ai.h2o.sparkling.ml.algos
 
-import ai.h2o.sparkling.frame.{H2OColumnType, H2OFrame}
+import ai.h2o.sparkling.{H2OColumnType, H2OFrame}
 import ai.h2o.sparkling.ml.models.H2OSupervisedMOJOModel
 import ai.h2o.sparkling.ml.params.H2OAlgoSupervisedParams
 import hex.Model
diff --git a/ml/src/main/scala/ai/h2o/sparkling/ml/features/H2OTargetEncoder.scala b/ml/src/main/scala/ai/h2o/sparkling/ml/features/H2OTargetEncoder.scala
index 5092487335..e82074475f 100644
--- a/ml/src/main/scala/ai/h2o/sparkling/ml/features/H2OTargetEncoder.scala
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/features/H2OTargetEncoder.scala
@@ -18,10 +18,10 @@
 package ai.h2o.sparkling.ml.features
 
 import ai.h2o.sparkling.backend.utils.RestCommunication
+import ai.h2o.sparkling.ml.internals.H2OModel
 import ai.h2o.sparkling.ml.models.{H2OTargetEncoderBase, H2OTargetEncoderModel}
 import ai.h2o.sparkling.ml.params.H2OAlgoParamsHelper
 import ai.h2o.sparkling.ml.utils.EstimatorCommonUtils
-import ai.h2o.sparkling.model.H2OModel
 import ai.h2o.targetencoding._
 import org.apache.spark.h2o.H2OContext
 import org.apache.spark.ml.Estimator
diff --git a/ml/src/main/scala/ai/h2o/sparkling/ml/features/H2OTargetEncoderModelUtils.scala b/ml/src/main/scala/ai/h2o/sparkling/ml/features/H2OTargetEncoderModelUtils.scala
index bc3ceab9bb..cc9c8095c7 100644
--- a/ml/src/main/scala/ai/h2o/sparkling/ml/features/H2OTargetEncoderModelUtils.scala
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/features/H2OTargetEncoderModelUtils.scala
@@ -17,7 +17,7 @@
 
 package ai.h2o.sparkling.ml.features
 
-import ai.h2o.sparkling.frame.H2OFrame
+import ai.h2o.sparkling.H2OFrame
 import ai.h2o.sparkling.ml.params.H2OTargetEncoderParams
 
 trait H2OTargetEncoderModelUtils extends H2OTargetEncoderParams {
diff --git a/core/src/main/scala/ai/h2o/sparkling/model/H2OMetric.java b/ml/src/main/scala/ai/h2o/sparkling/ml/internals/H2OMetric.java
similarity index 97%
rename from core/src/main/scala/ai/h2o/sparkling/model/H2OMetric.java
rename to ml/src/main/scala/ai/h2o/sparkling/ml/internals/H2OMetric.java
index 84f1386aea..cd16fb0f49 100644
--- a/core/src/main/scala/ai/h2o/sparkling/model/H2OMetric.java
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/internals/H2OMetric.java
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package ai.h2o.sparkling.model;
+package ai.h2o.sparkling.ml.internals;
 
 public enum H2OMetric {
     AUTO(true),
diff --git a/core/src/main/scala/ai/h2o/sparkling/model/H2OMetricsHolder.scala b/ml/src/main/scala/ai/h2o/sparkling/ml/internals/H2OMetricsHolder.scala
similarity index 71%
rename from core/src/main/scala/ai/h2o/sparkling/model/H2OMetricsHolder.scala
rename to ml/src/main/scala/ai/h2o/sparkling/ml/internals/H2OMetricsHolder.scala
index cf41fb0814..dad2ef9bca 100644
--- a/core/src/main/scala/ai/h2o/sparkling/model/H2OMetricsHolder.scala
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/internals/H2OMetricsHolder.scala
@@ -15,8 +15,8 @@
 * limitations under the License.
 */
 
-package ai.h2o.sparkling.model
+package ai.h2o.sparkling.ml.internals
 
-case class H2OMetricsHolder(trainingMetrics: Map[H2OMetric, Double],
-                            validationMetrics: Map[H2OMetric, Double],
-                            crossValidationMetrics: Map[H2OMetric, Double])
+private[sparkling] case class H2OMetricsHolder(trainingMetrics: Map[H2OMetric, Double],
+                                               validationMetrics: Map[H2OMetric, Double],
+                                               crossValidationMetrics: Map[H2OMetric, Double])
diff --git a/core/src/main/scala/ai/h2o/sparkling/model/H2OModel.scala b/ml/src/main/scala/ai/h2o/sparkling/ml/internals/H2OModel.scala
similarity index 97%
rename from core/src/main/scala/ai/h2o/sparkling/model/H2OModel.scala
rename to ml/src/main/scala/ai/h2o/sparkling/ml/internals/H2OModel.scala
index 5003a44539..9271e54a0d 100644
--- a/core/src/main/scala/ai/h2o/sparkling/model/H2OModel.scala
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/internals/H2OModel.scala
@@ -15,7 +15,7 @@
 * limitations under the License.
 */
 
-package ai.h2o.sparkling.model
+package ai.h2o.sparkling.ml.internals
 
 import java.io.File
 import java.nio.file.Files
@@ -31,7 +31,7 @@ import water.api.schemas3.ModelsV3
 import scala.collection.JavaConverters._
 
 
-class H2OModel private(val modelId: String,
+private[sparkling] class H2OModel private(val modelId: String,
                        val modelCategory: H2OModelCategory.Value,
                        val metrics: H2OMetricsHolder,
                        val trainingParams: Map[String, String])
@@ -57,7 +57,7 @@ class H2OModel private(val modelId: String,
   }
 }
 
-object H2OModel extends RestCommunication {
+private[sparkling] object H2OModel extends RestCommunication {
 
   private[sparkling] def listAllModels(): Array[String] = {
     val conf = H2OContext.ensure().getConf
diff --git a/core/src/main/scala/ai/h2o/sparkling/model/H2OModelCategory.scala b/ml/src/main/scala/ai/h2o/sparkling/ml/internals/H2OModelCategory.scala
similarity index 92%
rename from core/src/main/scala/ai/h2o/sparkling/model/H2OModelCategory.scala
rename to ml/src/main/scala/ai/h2o/sparkling/ml/internals/H2OModelCategory.scala
index 0f07662dad..7484c5b32b 100644
--- a/core/src/main/scala/ai/h2o/sparkling/model/H2OModelCategory.scala
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/internals/H2OModelCategory.scala
@@ -15,12 +15,12 @@
 * limitations under the License.
 */
 
-package ai.h2o.sparkling.model
+package ai.h2o.sparkling.ml.internals
 
 /**
  * Copied from H2O's class ModelCategory
  */
-object H2OModelCategory extends Enumeration {
+private[sparkling] object H2OModelCategory extends Enumeration {
   val Unknown, Binomial, Multinomial, Ordinal, Regression, HGLMRegression,
   Clustering, AutoEncoder, TargetEncoder, DimReduction, WordEmbedding, CoxPH,
   AnomalyDetection = Value
diff --git a/ml/src/main/scala/ai/h2o/sparkling/ml/models/H2OTargetEncoderModel.scala b/ml/src/main/scala/ai/h2o/sparkling/ml/models/H2OTargetEncoderModel.scala
index 937dfdcbdc..2cefa7f6cc 100644
--- a/ml/src/main/scala/ai/h2o/sparkling/ml/models/H2OTargetEncoderModel.scala
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/models/H2OTargetEncoderModel.scala
@@ -17,11 +17,11 @@
 
 package ai.h2o.sparkling.ml.models
 
+import ai.h2o.sparkling.H2OFrame
 import ai.h2o.sparkling.backend.utils.{RestApiUtils, RestCommunication}
-import ai.h2o.sparkling.frame.H2OFrame
+import ai.h2o.sparkling.ml.internals.H2OModel
 import ai.h2o.sparkling.ml.features.H2OTargetEncoderModelUtils
 import ai.h2o.sparkling.ml.utils.SchemaUtils
-import ai.h2o.sparkling.model.H2OModel
 import org.apache.spark.h2o.H2OContext
 import org.apache.spark.ml.Model
 import org.apache.spark.ml.param.ParamMap
diff --git a/ml/src/main/scala/ai/h2o/sparkling/ml/params/H2OGridSearchParams.scala b/ml/src/main/scala/ai/h2o/sparkling/ml/params/H2OGridSearchParams.scala
index c17ceabf0e..9f7f5b4a95 100644
--- a/ml/src/main/scala/ai/h2o/sparkling/ml/params/H2OGridSearchParams.scala
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/params/H2OGridSearchParams.scala
@@ -19,7 +19,7 @@ package ai.h2o.sparkling.ml.params
 import java.util
 
 import ai.h2o.sparkling.ml.algos.{H2OGridSearch, H2OSupervisedAlgorithm}
-import ai.h2o.sparkling.model.H2OMetric
+import ai.h2o.sparkling.ml.internals.H2OMetric
 import hex.grid.HyperSpaceSearchCriteria
 import hex.{Model, ScoreKeeper}
 import org.apache.spark.ml.param._
diff --git a/ml/src/main/scala/ai/h2o/sparkling/ml/utils/EstimatorCommonUtils.scala b/ml/src/main/scala/ai/h2o/sparkling/ml/utils/EstimatorCommonUtils.scala
index 3499f05ac3..6ef89fbf6d 100644
--- a/ml/src/main/scala/ai/h2o/sparkling/ml/utils/EstimatorCommonUtils.scala
+++ b/ml/src/main/scala/ai/h2o/sparkling/ml/utils/EstimatorCommonUtils.scala
@@ -16,8 +16,8 @@
 */
 package ai.h2o.sparkling.ml.utils
 
+import ai.h2o.sparkling.backend.H2OJob
 import ai.h2o.sparkling.backend.utils.{RestApiUtils, RestCommunication}
-import ai.h2o.sparkling.job.H2OJob
 import hex.schemas.ModelBuilderSchema
 import org.apache.spark.h2o.H2OContext
 
diff --git a/ml/src/test/scala/ai/h2o/sparkling/ml/algos/H2OGLMTestSuite.scala b/ml/src/test/scala/ai/h2o/sparkling/ml/algos/H2OGLMTestSuite.scala
index d850b13398..f8cc0ca351 100644
--- a/ml/src/test/scala/ai/h2o/sparkling/ml/algos/H2OGLMTestSuite.scala
+++ b/ml/src/test/scala/ai/h2o/sparkling/ml/algos/H2OGLMTestSuite.scala
@@ -17,7 +17,7 @@
 
 package ai.h2o.sparkling.ml.algos
 
-import ai.h2o.sparkling.model.H2OModel
+import ai.h2o.sparkling.ml.internals.H2OModel
 import org.apache.spark.SparkContext
 import org.apache.spark.h2o.utils.SharedH2OTestContext
 import org.apache.spark.ml.{Pipeline, PipelineModel}
diff --git a/py/src/ai/h2o/sparkling/ml/params/H2OGridSearchParams.py b/py/src/ai/h2o/sparkling/ml/params/H2OGridSearchParams.py
index c5e8c1805f..8c55af3036 100644
--- a/py/src/ai/h2o/sparkling/ml/params/H2OGridSearchParams.py
+++ b/py/src/ai/h2o/sparkling/ml/params/H2OGridSearchParams.py
@@ -76,7 +76,7 @@ class H2OGridSearchParams(H2OCommonSupervisedParams):
         Params._dummy(),
         "selectBestModelBy",
         "Specifies the metric which is used for comparing and sorting the models returned by the grid.",
-        H2OTypeConverters.toEnumString("ai.h2o.sparkling.model.H2OMetric"))
+        H2OTypeConverters.toEnumString("ai.h2o.sparkling.ml.internals.H2OMetric"))
 
     parallelism = Param(
         Params._dummy(),