diff --git a/pom.xml b/pom.xml
index e731b04..1336ae9 100644
--- a/pom.xml
+++ b/pom.xml
@@ -35,6 +35,11 @@
       <artifactId>jackson-databind</artifactId>
       <version>2.17.0</version>
     </dependency>
+    <dependency>
+      <groupId>com.fasterxml.jackson.datatype</groupId>
+      <artifactId>jackson-datatype-jsr310</artifactId>
+      <version>2.17.0</version>
+    </dependency>
     <dependency>
       <groupId>org.apache.commons</groupId>
       <artifactId>commons-math3</artifactId>
diff --git a/src/main/java/de/ph87/electro/circuit/Circuit.java b/src/main/java/de/ph87/electro/circuit/Circuit.java
index ed8956e..5da2bcb 100644
--- a/src/main/java/de/ph87/electro/circuit/Circuit.java
+++ b/src/main/java/de/ph87/electro/circuit/Circuit.java
@@ -27,7 +27,7 @@ import static de.ph87.electro.circuit.CircuitIOService.write;
 public class Circuit {
 
   @Getter
-  private final ZonedDateTime created;
+  private final String created;
 
   private final List<Part> parts = new ArrayList<>();
 
@@ -36,7 +36,7 @@ public class Circuit {
   private boolean dirty = false;
 
   public Circuit() {
-    this.created = ZonedDateTime.now();
+    this.created = ZonedDateTime.now().format(DateTimeFormatter.ISO_OFFSET_DATE_TIME);
   }
 
   public Circuit(final CircuitDto dto) {
@@ -100,7 +100,7 @@ public class Circuit {
       return;
     }
     try {
-      final File file = new File("./data/%s.json".formatted(created.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME)));
+      final File file = new File("./data/%s.json".formatted(created));
       if (file.getParentFile().mkdirs()) {
         log.info("Directory created: {}", file.getParent());
       }
diff --git a/src/main/java/de/ph87/electro/circuit/CircuitDto.java b/src/main/java/de/ph87/electro/circuit/CircuitDto.java
index 5f0abf0..fc4b866 100644
--- a/src/main/java/de/ph87/electro/circuit/CircuitDto.java
+++ b/src/main/java/de/ph87/electro/circuit/CircuitDto.java
@@ -6,7 +6,6 @@ import lombok.Getter;
 import lombok.NoArgsConstructor;
 import lombok.ToString;
 
-import java.time.ZonedDateTime;
 import java.util.List;
 
 @Getter
@@ -14,7 +13,7 @@ import java.util.List;
 @NoArgsConstructor
 public class CircuitDto {
 
-  private ZonedDateTime created;
+  private String created;
 
   private List<PartDto> parts;
 
diff --git a/src/test/java/de/ph87/electro/circuit/io/CircuitIOServiceTest.java b/src/test/java/de/ph87/electro/circuit/io/CircuitIOServiceTest.java
index ce310a1..829d40b 100644
--- a/src/test/java/de/ph87/electro/circuit/io/CircuitIOServiceTest.java
+++ b/src/test/java/de/ph87/electro/circuit/io/CircuitIOServiceTest.java
@@ -38,6 +38,7 @@ class CircuitIOServiceTest {
     final ByteArrayInputStream input = new ByteArrayInputStream(output.toByteArray());
     final Circuit reloaded = read(input);
 
+    assertEquals(original.getCreated(), reloaded.getCreated());
     assertEquals(original.getPartCount(), reloaded.getPartCount());
     original.streamParts().forEach(originalPart -> {
       System.out.printf("Part: %s\n", originalPart.getUuid());