diff --git a/api/server/src/main/java/org/softwareheritage/graph/SwhId.java b/api/server/src/main/java/org/softwareheritage/graph/SwhId.java
index 375ff81..a3f9e14 100644
--- a/api/server/src/main/java/org/softwareheritage/graph/SwhId.java
+++ b/api/server/src/main/java/org/softwareheritage/graph/SwhId.java
@@ -1,31 +1,38 @@
 package org.softwareheritage.graph;
 
+import com.fasterxml.jackson.annotation.JsonValue;
+
 public class SwhId {
   String swhId;
   String type;
   String hash;
 
   public SwhId(String swhId) {
     this.swhId = swhId;
     String[] parts = swhId.split(":");
     if (parts.length != 4) {
       throw new IllegalArgumentException("Incorrect SWH ID format: " + swhId);
     }
 
     // SWH ID format: 'swh:1:type:hash'
     this.type = parts[2];
     this.hash = parts[3];
   }
 
+  @JsonValue
+  public String getSwhId() {
+    return swhId;
+  }
+
   public String getType() {
     return type;
   }
 
   public String getHash() {
     return hash;
   }
 
   public String toString() {
     return swhId;
   }
 }