diff --git a/src/main/java/org/araymond/joalcore/core/trackers/domain/TiersSelectionMode.java b/src/main/java/org/araymond/joalcore/core/trackers/domain/TiersSelectionMode.java
new file mode 100644
index 00000000..13d7ccfc
--- /dev/null
+++ b/src/main/java/org/araymond/joalcore/core/trackers/domain/TiersSelectionMode.java
@@ -0,0 +1,4 @@
+package org.araymond.joalcore.core.trackers.domain;
+
+public interface TiersSelectionMode {
+}
diff --git a/src/main/java/org/araymond/joalcore/core/trackers/domain/Tracker.java b/src/main/java/org/araymond/joalcore/core/trackers/domain/Tracker.java
new file mode 100644
index 00000000..95dde737
--- /dev/null
+++ b/src/main/java/org/araymond/joalcore/core/trackers/domain/Tracker.java
@@ -0,0 +1,4 @@
+package org.araymond.joalcore.core.trackers.domain;
+
+public class Tracker {
+}
diff --git a/src/main/java/org/araymond/joalcore/core/trackers/domain/TrackerSelectionMode.java b/src/main/java/org/araymond/joalcore/core/trackers/domain/TrackerSelectionMode.java
new file mode 100644
index 00000000..6600bc1a
--- /dev/null
+++ b/src/main/java/org/araymond/joalcore/core/trackers/domain/TrackerSelectionMode.java
@@ -0,0 +1,4 @@
+package org.araymond.joalcore.core.trackers.domain;
+
+public interface TrackerSelectionMode {
+}
diff --git a/src/main/java/org/araymond/joalcore/core/trackers/domain/TrackerTier.java b/src/main/java/org/araymond/joalcore/core/trackers/domain/TrackerTier.java
new file mode 100644
index 00000000..6f2eedc7
--- /dev/null
+++ b/src/main/java/org/araymond/joalcore/core/trackers/domain/TrackerTier.java
@@ -0,0 +1,5 @@
+package org.araymond.joalcore.core.trackers.domain;
+
+public class TrackerTier {
+    // TODO: use a TrackerSelectionMode (qui aura deux implem: Fallback or AllAtOnce)
+}