diff --git a/js/src/api/types.ts b/js/src/api/types.ts
index 629e144..1583c24 100644
--- a/js/src/api/types.ts
+++ b/js/src/api/types.ts
@@ -127,7 +127,10 @@ const ParticleBaseSchema = z.object({
   id: z.string(),
   created_at: z.coerce.date(),
   created_by_email: z.string().email(),
-  updated_at: z.coerce.date().optional()
+  updated_at: z.coerce.date().optional(),
+  // e.g. ["human:aron@acme.com", "human:john@acme.com"] - visible only to Aron and John
+  // e.g. ["network:123"] - visible to everyone in the network
+  visible_to: z.array(z.string())
 });
 
 export const ParticleSchema = z.discriminatedUnion("type", [
diff --git a/js/src/hooks/use-create-particle.ts b/js/src/hooks/use-create-particle.ts
index f86a915..d6df5b0 100644
--- a/js/src/hooks/use-create-particle.ts
+++ b/js/src/hooks/use-create-particle.ts
@@ -7,6 +7,7 @@ interface CreateParticleParams<T extends ParticleType = ParticleType> {
   type: T;
   properties: ParticlePropertiesMap[T];
   createdByEmail: string;
+  visibleTo: string[];
 }
 
 export function useCreateParticle() {
@@ -17,6 +18,7 @@ export function useCreateParticle() {
         params.type,
         params.properties,
         params.createdByEmail,
+        params.visibleTo,
       ),
   });
 }
diff --git a/js/src/lib/firestore-particles.ts b/js/src/lib/firestore-particles.ts
index ccb298a..961860b 100644
--- a/js/src/lib/firestore-particles.ts
+++ b/js/src/lib/firestore-particles.ts
@@ -41,6 +41,7 @@ const particleConverter: FirestoreDataConverter<Particle> = {
       created_at: (raw.created_at as Timestamp).toDate(),
       created_by_email: raw.created_by_email,
       updated_at: raw.updated_at ? (raw.updated_at as Timestamp).toDate() : undefined,
+      visible_to: raw.visible_to,
     });
   },
 };
@@ -91,6 +92,7 @@ export async function createParticle<T extends ParticleType>(
   type: T,
   properties: ParticlePropertiesMap[T],
   createdByEmail: string,
+  visibleTo: string[],
 ): Promise<string> {
   const particle: Particle = ParticleSchema.parse({
     id: "", // ignored by toFirestore, but needed to satisfy the type
@@ -99,6 +101,7 @@ export async function createParticle<T extends ParticleType>(
     created_at: new Date(),
     created_by_email: createdByEmail,
     updated_at: null,
+    visible_to: visibleTo,
   });
   const ref = await addDoc(typedCollection(collectionPath), particle);
   return ref.id;
@@ -108,6 +111,7 @@ export async function createParticle<T extends ParticleType>(
 export async function updateParticle<T extends ParticleType>(
   docPath: string,
   properties: Partial<ParticlePropertiesMap[T]>,
+  visibleTo?: string[],
 ): Promise<void> {
   const particleRef = typedDoc(docPath);
   // Take the partial and create a new object with dot notation
@@ -119,5 +123,6 @@ export async function updateParticle<T extends ParticleType>(
   await updateDoc(particleRef, {
     ...updatedProperties,
     updated_at: serverTimestamp(),
+    ...(visibleTo ? { visible_to: visibleTo } : {}),
   });
 }