diff --git a/build.gradle.kts b/build.gradle.kts
index 470cb78..9659488 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -29,6 +29,7 @@ repositories {
 
 dependencies {
     compileOnly("org.jetbrains:annotations:26.0.2-1")
+    implementation("com.r35157.libs:valuetypes-basic-api:0.1-dev")
 }
 
 java {
diff --git a/src/main/java/com/r35157/nenjim/hubd/Id.java b/src/main/java/com/r35157/nenjim/hubd/Id.java
new file mode 100644
index 0000000..04523c8
--- /dev/null
+++ b/src/main/java/com/r35157/nenjim/hubd/Id.java
@@ -0,0 +1,6 @@
+package com.r35157.nenjim.hubd;
+
+/**
+ * Id is the super tag for all kinds of id value types.
+ */
+public interface Id {}
diff --git a/src/main/java/com/r35157/nenjim/hubd/NenjimDependency.java b/src/main/java/com/r35157/nenjim/hubd/NenjimDependency.java
new file mode 100644
index 0000000..cb9a7e0
--- /dev/null
+++ b/src/main/java/com/r35157/nenjim/hubd/NenjimDependency.java
@@ -0,0 +1,8 @@
+package com.r35157.nenjim.hubd;
+
+import org.jetbrains.annotations.NotNull;
+
+public record NenjimDependency(
+        @NotNull NenjimJournalId dependencyId
+) {
+}
diff --git a/src/main/java/com/r35157/nenjim/hubd/NenjimHub.java b/src/main/java/com/r35157/nenjim/hubd/NenjimHub.java
index 24f4a84..7c42830 100644
--- a/src/main/java/com/r35157/nenjim/hubd/NenjimHub.java
+++ b/src/main/java/com/r35157/nenjim/hubd/NenjimHub.java
@@ -1,9 +1,17 @@
 package com.r35157.nenjim.hubd;
 
+import org.jetbrains.annotations.NotNull;
+
 public interface NenjimHub {
     /**
      * A no-operation (noop). This method is suppoted to do nothing.
      */
     void noop();
+
+    /**
+     *
+     * @param journal
+     */
+    void monitorJournal(@NotNull NenjimJournal journal);
 }
 
diff --git a/src/main/java/com/r35157/nenjim/hubd/NenjimJournal.java b/src/main/java/com/r35157/nenjim/hubd/NenjimJournal.java
new file mode 100644
index 0000000..7294b78
--- /dev/null
+++ b/src/main/java/com/r35157/nenjim/hubd/NenjimJournal.java
@@ -0,0 +1,16 @@
+package com.r35157.nenjim.hubd;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Set;
+
+/**
+ * A Nenjim Journal is a manifest that describes a Nenjim component and its dependencies.
+ * It lists the required dependent modules with version constraints and enough metadata (e.g. checksums/signatures)
+ * for Nenjim to resolve, verify, and cache the correct artifacts.
+ */
+public record NenjimJournal (
+    @NotNull NenjimJournalId id,
+    @NotNull String name,
+    @NotNull Set<NenjimRelease> releases
+) implements Id {}
diff --git a/src/main/java/com/r35157/nenjim/hubd/NenjimJournalId.java b/src/main/java/com/r35157/nenjim/hubd/NenjimJournalId.java
new file mode 100644
index 0000000..9706841
--- /dev/null
+++ b/src/main/java/com/r35157/nenjim/hubd/NenjimJournalId.java
@@ -0,0 +1,7 @@
+package com.r35157.nenjim.hubd;
+
+import org.jetbrains.annotations.NotNull;
+
+public record NenjimJournalId(
+    @NotNull String value
+) implements Id {}
diff --git a/src/main/java/com/r35157/nenjim/hubd/NenjimRelease.java b/src/main/java/com/r35157/nenjim/hubd/NenjimRelease.java
new file mode 100644
index 0000000..b6cd279
--- /dev/null
+++ b/src/main/java/com/r35157/nenjim/hubd/NenjimRelease.java
@@ -0,0 +1,8 @@
+package com.r35157.nenjim.hubd;
+
+import com.r35157.libs.valuetypes.basic.SemanticVersion;
+import org.jetbrains.annotations.NotNull;
+
+public record NenjimRelease(
+        @NotNull SemanticVersion version
+) {}