diff --git a/app/src/main/java/it/danieleverducci/subitobeers/BeerNavigation.kt b/app/src/main/java/it/danieleverducci/subitobeers/BeerNavigation.kt
index 7a79cbd..0fe08ce 100644
--- a/app/src/main/java/it/danieleverducci/subitobeers/BeerNavigation.kt
+++ b/app/src/main/java/it/danieleverducci/subitobeers/BeerNavigation.kt
@@ -2,6 +2,9 @@ package it.danieleverducci.subitobeers
 
 import it.danieleverducci.subitobeers.entities.Beer
 
+/**
+ * Fragment navigation interface
+ */
 interface BeerNavigation {
     fun showBeerDetail(beer: Beer)
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/danieleverducci/subitobeers/BeersRepository.kt b/app/src/main/java/it/danieleverducci/subitobeers/BeersRepository.kt
index 910ca25..8f1116c 100644
--- a/app/src/main/java/it/danieleverducci/subitobeers/BeersRepository.kt
+++ b/app/src/main/java/it/danieleverducci/subitobeers/BeersRepository.kt
@@ -9,6 +9,10 @@ import retrofit2.Call
 import retrofit2.Callback
 import retrofit2.Response
 
+/**
+ * Beers repository
+ * Allows to retrieve beers from Punk API via its Retrofit implementation
+ */
 class BeersRepository {
 
     companion object {
@@ -23,6 +27,7 @@ class BeersRepository {
     /**
      * Obtain a paginated list of beers from the server
      * Use page property to set the page
+     * Async: will call listener's onResponse() or onFailure()
      */
     fun getBeers() {
         // Obtain beers
@@ -54,6 +59,9 @@ class BeersRepository {
         more = true
     }
 
+    /**
+     * Listener for api callbacks
+     */
     interface Listener {
         fun onBeersObtained(beers: List<Beer>, more: Boolean)
         fun onFailure()
diff --git a/app/src/main/java/it/danieleverducci/subitobeers/Config.kt b/app/src/main/java/it/danieleverducci/subitobeers/Config.kt
index f607474..9d3c3d7 100644
--- a/app/src/main/java/it/danieleverducci/subitobeers/Config.kt
+++ b/app/src/main/java/it/danieleverducci/subitobeers/Config.kt
@@ -1,5 +1,8 @@
 package it.danieleverducci.subitobeers
 
+/**
+ * Static configuration file
+ */
 object Config {
     val API_BASEURL = "https://api.punkapi.com/"
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/danieleverducci/subitobeers/MainActivity.kt b/app/src/main/java/it/danieleverducci/subitobeers/MainActivity.kt
index 4b1c352..8160552 100644
--- a/app/src/main/java/it/danieleverducci/subitobeers/MainActivity.kt
+++ b/app/src/main/java/it/danieleverducci/subitobeers/MainActivity.kt
@@ -8,6 +8,10 @@ import androidx.fragment.app.FragmentManager
 import it.danieleverducci.subitobeers.entities.Beer
 import it.danieleverducci.subitobeers.ui.BeerDetailFragment
 
+/**
+ * App entrypoint
+ * An activity with two fragments (list + detail)
+ */
 class MainActivity : AppCompatActivity(), BeerNavigation {
 
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -15,6 +19,10 @@ class MainActivity : AppCompatActivity(), BeerNavigation {
         setContentView(R.layout.activity_main)
     }
 
+    /**
+     * Show beer detail fragment
+     * @param beer to show in detail
+     */
     override fun showBeerDetail(beer: Beer) {
         val detailFragment = BeerDetailFragment(beer)
         supportFragmentManager.beginTransaction()
@@ -25,6 +33,7 @@ class MainActivity : AppCompatActivity(), BeerNavigation {
     }
 
     override fun onBackPressed() {
+        // Manage fragment navigation
         val bsf = supportFragmentManager.backStackEntryCount
         if(bsf == 0) {
             super.onBackPressed()
diff --git a/app/src/main/java/it/danieleverducci/subitobeers/entities/Beer.kt b/app/src/main/java/it/danieleverducci/subitobeers/entities/Beer.kt
index 20f17cb..69e93b0 100644
--- a/app/src/main/java/it/danieleverducci/subitobeers/entities/Beer.kt
+++ b/app/src/main/java/it/danieleverducci/subitobeers/entities/Beer.kt
@@ -2,6 +2,9 @@ package it.danieleverducci.subitobeers.entities
 
 import com.google.gson.annotations.SerializedName
 
+/**
+ * Represents a Punk API's (https://punkapi.com/documentation/v2) beer item
+ */
 class Beer {
     val id: Int = 0
     val name: String = ""
diff --git a/app/src/main/java/it/danieleverducci/subitobeers/networking/BeersFilter.kt b/app/src/main/java/it/danieleverducci/subitobeers/networking/BeersFilter.kt
index 12d2c99..cca0504 100644
--- a/app/src/main/java/it/danieleverducci/subitobeers/networking/BeersFilter.kt
+++ b/app/src/main/java/it/danieleverducci/subitobeers/networking/BeersFilter.kt
@@ -3,6 +3,9 @@ package it.danieleverducci.subitobeers.networking
 import android.util.Log
 import java.util.*
 
+/**
+ * Class to represent a beer filter. Filters by brewing date.
+ */
 class BeersFilter {
     // The date format is like "09/2007" (MM/YYYY). Month start from 1.
     var brewedBefore: String? = null
@@ -17,6 +20,9 @@ class BeersFilter {
     val brewedAfterMonth: Int
             get() = getMonth(brewedAfter)
 
+    /**
+     * Clears filter
+     */
     fun clear() {
         brewedBefore = null
         brewedAfter = null
diff --git a/app/src/main/java/it/danieleverducci/subitobeers/networking/PunkAPI.kt b/app/src/main/java/it/danieleverducci/subitobeers/networking/PunkAPI.kt
index a0596e7..d1af751 100644
--- a/app/src/main/java/it/danieleverducci/subitobeers/networking/PunkAPI.kt
+++ b/app/src/main/java/it/danieleverducci/subitobeers/networking/PunkAPI.kt
@@ -5,11 +5,16 @@ import retrofit2.Call
 import retrofit2.http.GET
 import retrofit2.http.Query
 
+/**
+ * Punk API description for Retrofit
+ */
 interface PunkAPI {
+
     @GET("/v2/beers?per_page=10")
     fun getBeers(
         @Query("page") page: Int,
         @Query("brewed_before") brewedBefore: String?,
         @Query("brewed_after") brewedAfter: String?
     ): Call<List<Beer>>
+
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/danieleverducci/subitobeers/networking/RetrofitProvider.kt b/app/src/main/java/it/danieleverducci/subitobeers/networking/RetrofitProvider.kt
index bd6757e..efc998c 100644
--- a/app/src/main/java/it/danieleverducci/subitobeers/networking/RetrofitProvider.kt
+++ b/app/src/main/java/it/danieleverducci/subitobeers/networking/RetrofitProvider.kt
@@ -7,7 +7,14 @@ import okhttp3.OkHttpClient
 import retrofit2.Retrofit
 import retrofit2.converter.gson.GsonConverterFactory
 
+/**
+ * Provider for Punk API Retrofit implementation
+ */
 object RetrofitProvider {
+
+    /**
+     * Punk API Retrofit client
+     */
     val getClient: PunkAPI
     get() {
 
diff --git a/app/src/main/java/it/danieleverducci/subitobeers/ui/BeerDetailFragment.kt b/app/src/main/java/it/danieleverducci/subitobeers/ui/BeerDetailFragment.kt
index a3d0715..153a532 100644
--- a/app/src/main/java/it/danieleverducci/subitobeers/ui/BeerDetailFragment.kt
+++ b/app/src/main/java/it/danieleverducci/subitobeers/ui/BeerDetailFragment.kt
@@ -10,6 +10,9 @@ import it.danieleverducci.subitobeers.R
 import it.danieleverducci.subitobeers.databinding.FragmentBeerDetailBinding
 import it.danieleverducci.subitobeers.entities.Beer
 
+/**
+ * A simple beer detail fragment, with an image and some textual data
+ */
 class BeerDetailFragment(val beer: Beer) : Fragment() {
 
     lateinit var binding: FragmentBeerDetailBinding
diff --git a/app/src/main/java/it/danieleverducci/subitobeers/ui/BeerRecyclerAdapter.kt b/app/src/main/java/it/danieleverducci/subitobeers/ui/BeerRecyclerAdapter.kt
index 4919d62..16c7a1c 100644
--- a/app/src/main/java/it/danieleverducci/subitobeers/ui/BeerRecyclerAdapter.kt
+++ b/app/src/main/java/it/danieleverducci/subitobeers/ui/BeerRecyclerAdapter.kt
@@ -13,6 +13,9 @@ import it.danieleverducci.subitobeers.R
 import it.danieleverducci.subitobeers.databinding.FragmentBeersListitemBinding
 import it.danieleverducci.subitobeers.entities.Beer
 
+/**
+ * RecyclerAdapter for beers list RecyclerView
+ */
 class BeerRecyclerAdapter : RecyclerView.Adapter<BeerRecyclerAdapter.ViewHolder>() {
 
     // The click event listener
@@ -102,6 +105,9 @@ class BeerRecyclerAdapter : RecyclerView.Adapter<BeerRecyclerAdapter.ViewHolder>
         val progress: ProgressBar = binding.beerItemProgress
     }
 
+    /**
+     * List event listener
+     */
     interface Listener {
         fun OnItemClicked(item: Beer)
         fun OnLastItemScrolled()