diff --git a/apple/OmnivoreKit/Sources/Models/DataModels/Highlight.swift b/apple/OmnivoreKit/Sources/Models/DataModels/Highlight.swift
index 0f78f36ef..182f71364 100644
--- a/apple/OmnivoreKit/Sources/Models/DataModels/Highlight.swift
+++ b/apple/OmnivoreKit/Sources/Models/DataModels/Highlight.swift
@@ -2,9 +2,7 @@ import CoreData
 import Foundation
 
 public extension Highlight {
-  var unwrappedID: String {
-    id ?? ""
-  }
+  var unwrappedID: String { id ?? "" }
 
   static func lookup(byID highlightID: String, inContext context: NSManagedObjectContext) -> Highlight? {
     let fetchRequest: NSFetchRequest<Models.Highlight> = Highlight.fetchRequest()
diff --git a/apple/OmnivoreKit/Sources/Services/DataService/Errors/ServerError.swift b/apple/OmnivoreKit/Sources/Services/DataService/Errors/ServerError.swift
index f71a87f59..c3781974f 100644
--- a/apple/OmnivoreKit/Sources/Services/DataService/Errors/ServerError.swift
+++ b/apple/OmnivoreKit/Sources/Services/DataService/Errors/ServerError.swift
@@ -1,6 +1,10 @@
 import Foundation
 import Models
 
+public enum CoreDataError: Error {
+  case general
+}
+
 public enum ServerError: String, Error {
   case noConnection
   case unauthenticated
diff --git a/apple/OmnivoreKit/Sources/Services/DataService/Mutations/MergeHighlight.swift b/apple/OmnivoreKit/Sources/Services/DataService/Mutations/MergeHighlight.swift
index d5a0ea97d..5b3c9d5f8 100644
--- a/apple/OmnivoreKit/Sources/Services/DataService/Mutations/MergeHighlight.swift
+++ b/apple/OmnivoreKit/Sources/Services/DataService/Mutations/MergeHighlight.swift
@@ -4,7 +4,7 @@ import Models
 import SwiftGraphQL
 
 extension DataService {
-  // swiftlint:disable:next function_parameter_count function_body_length
+  // swiftlint:disable:next function_parameter_count
   public func mergeHighlights(
     shortId: String,
     highlightID: String,
diff --git a/apple/OmnivoreKit/Sources/Services/DataService/OfflineSync.swift b/apple/OmnivoreKit/Sources/Services/DataService/OfflineSync.swift
new file mode 100644
index 000000000..ea89ccce3
--- /dev/null
+++ b/apple/OmnivoreKit/Sources/Services/DataService/OfflineSync.swift
@@ -0,0 +1,85 @@
+import CoreData
+import Foundation
+import Models
+
+extension DataService {
+  func syncOfflineItemsWithServerIfNeeded() async throws {
+    // TODO: send a simple request to see if we're online?
+    var unsyncedLinkedItems = [LinkedItem]()
+    var unsyncedHighlights = [Highlight]()
+
+    // LinkedItems
+    let itemsFetchRequest: NSFetchRequest<Models.LinkedItem> = LinkedItem.fetchRequest()
+    itemsFetchRequest.predicate = NSPredicate(
+      format: "serverSyncStatus != %@", ServerSyncStatus.isNSync.rawValue
+    )
+
+    // Highlights
+    let highlightsFetchRequest: NSFetchRequest<Models.Highlight> = Highlight.fetchRequest()
+    highlightsFetchRequest.predicate = NSPredicate(
+      format: "serverSyncStatus != %@", ServerSyncStatus.isNSync.rawValue
+    )
+
+    try await backgroundContext.perform(schedule: .immediate) { [weak self] in
+      guard let self = self else { return }
+
+      do {
+        unsyncedLinkedItems = try itemsFetchRequest.execute()
+        unsyncedHighlights = try highlightsFetchRequest.execute()
+      } catch {
+        throw CoreDataError.general
+      }
+
+      self.syncLinkedItems(unsyncedLinkedItems: unsyncedLinkedItems)
+      self.syncHighlights(unsyncedHighlights: unsyncedHighlights)
+    }
+  }
+
+  private func syncLinkedItems(unsyncedLinkedItems: [LinkedItem]) {
+    for item in unsyncedLinkedItems {
+      guard let syncStatus = ServerSyncStatus(rawValue: Int(item.serverSyncStatus)) else { continue }
+
+      switch syncStatus {
+      case .isNSync, .isSyncing, .needsCreation:
+        break
+      case .needsDeletion:
+        item.serverSyncStatus = Int64(ServerSyncStatus.isSyncing.rawValue)
+        syncLinkDeletion(itemID: item.unwrappedID, objectID: item.objectID)
+      case .needsUpdate:
+        item.serverSyncStatus = Int64(ServerSyncStatus.isSyncing.rawValue)
+        syncLinkArchiveStatus(itemID: item.unwrappedID, objectID: item.objectID, archived: item.isArchived)
+      }
+    }
+  }
+
+  private func syncHighlights(unsyncedHighlights: [Highlight]) {
+    for highlight in unsyncedHighlights {
+      guard let syncStatus = ServerSyncStatus(rawValue: Int(highlight.serverSyncStatus)) else { continue }
+
+      switch syncStatus {
+      case .isNSync, .isSyncing:
+        break
+      case .needsCreation:
+        highlight.serverSyncStatus = Int64(ServerSyncStatus.isSyncing.rawValue)
+        syncHighlightCreation(
+          highlight: InternalHighlight.make(from: highlight),
+          articleId: highlight.linkedItem?.unwrappedID ?? ""
+        )
+      case .needsDeletion:
+        highlight.serverSyncStatus = Int64(ServerSyncStatus.isSyncing.rawValue)
+        syncHighlightDeletion(highlightID: highlight.unwrappedID, objectID: highlight.objectID)
+      case .needsUpdate:
+        if let annotation = highlight.annotation {
+          highlight.serverSyncStatus = Int64(ServerSyncStatus.isSyncing.rawValue)
+          syncHighlightAttributes(
+            highlightID: highlight.unwrappedID,
+            objectID: highlight.objectID,
+            annotation: annotation
+          )
+        } else {
+          highlight.serverSyncStatus = Int64(ServerSyncStatus.isNSync.rawValue)
+        }
+      }
+    }
+  }
+}