Best Backend for iOS Apps in 2026 (SwiftUI Compared)

The best backend for an iOS app depends on two questions: will the app ever need Android or web, and is your data relational? Apple-only apps that store each user's data privately are well served by CloudKit. Apps that will go cross-platform and want a mature, mobile-first toolkit often pick Firebase. If your data is relational (users, teams, orders, permissions) and you want SQL, a Postgres backend with a native Swift SDK, such as Supabase or StitchDB, fits best.

#What an iOS backend has to do

Before comparing, list the jobs. Most SwiftUI apps need:

1. Sign-in, including Sign in with Apple (often required by App Store guideline 4.8 when you offer other social logins) and in-app account deletion (guideline 5.1.1(v)).
2. Data with per-user and per-team access rules.
3. Files such as avatars and photos.
4. Push notifications through APNs.
5. Purchases: checking StoreKit 2 transactions on the server so paid features cannot be unlocked by editing the app.
6. Server code for things the app must not do itself (payments, e-mails, AI calls).
7. Offline behavior that does not lose edits.

#Quick comparison

Sources: Firebase pricing, Supabase pricing, StitchDB pricing.

#The options

#CloudKit

Apple's CloudKit stores app data in iCloud and syncs it across iOS, iPadOS, macOS, tvOS, watchOS, visionOS and the web. Private data lives in each user's own iCloud account, and Apple advertises up to 1 PB of storage for an app's public data (CloudKit).

• Pros: native Apple APIs, automatic syncing across a user's devices, private data stays in the user's iCloud account rather than your own database.
• Cons: Apple's page lists Apple platforms and the web, not Android. Querying across users, admin dashboards, analytics and server-side business logic are harder than with SQL.
• Pick it if the app is Apple-only and each user's data is mostly their own.

#Firebase

Firebase's Apple SDK installs with Swift Package Manager (Xcode 26.2 or later, iOS 15 or later) and covers Authentication, Cloud Firestore, Realtime Database, Cloud Storage, Cloud Functions, Cloud Messaging, Crashlytics, Remote Config, App Check and more (Firebase iOS setup). FCM is listed as a no-cost product.

• Pros: very mature on mobile, one vendor for many app services, generous free tier.
• Cons: Firestore is a document database, so joins, reports and many-to-many relations take more work; access rules are written in Firebase Security Rules; Firestore quotas are counted in document reads and writes, so chatty screens add up.
• Pick it if you are cross-platform from day one and your data fits documents. Compare more in Firebase alternatives.

#Supabase

Supabase gives each project a Postgres database with Auth, a REST API, Storage, Realtime and Edge Functions, and has an official Swift library, supabase-swift. As of November 2026 the Free plan includes 50,000 MAU and Pro starts at $25/month; free projects pause after one week of inactivity.

• Pros: SQL and Row Level Security, a large community, regions around the world.
• Cons: check which app services, such as push delivery or StoreKit validation, you would build yourself with functions and other vendors.
• Pick it if you want Postgres and need regions outside Europe.

#AWS Amplify

Amplify for Swift connects iOS apps to AWS for data modeling, authentication, storage and serverless functions (Amplify Swift docs).

• Pros: the whole of AWS behind it, good for companies already standardized on AWS.
• Cons: you are working with several AWS services and their separate pricing and consoles.
• Pick it if your company already runs on AWS.

#StitchDB

StitchDB gives each project a dedicated Postgres database with Auth, REST and GraphQL APIs, Realtime, Storage and Edge Functions, plus app services an iOS app usually adds separately: push notifications, StoreKit purchase checks, feature flags, crash reporting and offline sync. The Swift SDK (version 1.4.0) needs Swift 6.1 (Xcode 16.3) or newer, installs with Swift Package Manager and runs on iOS, macOS, tvOS, watchOS, visionOS and Linux.

• Pros: relational data with Row Level Security; sign-in methods including Apple, passkeys and MFA; APNs push and StoreKit 2 checks in the same SDK; sessions stored in the keychain; supabase-swift and other Supabase client libraries also work by changing the URL and keys (compatibility).
• Cons: hosted in EU data centers only (Germany and Finland), so users in the Americas or Asia see longer round trips; a younger platform than Firebase; no self-hosted edition.
• Pick it if you want SQL, auth, push and purchases in one project and EU hosting suits you.

#What a SwiftUI backend looks like on StitchDB

Add the package in Xcode (File › Add Package Dependencies…, https://github.com/stitchdb/stitchdb-swift.git) and create one shared client:

import StitchDB

let stitchdb = StitchClient(
  stitchURL: URL(string: "https://<project-ref>.p.stitchdb.com")!,
  stitchKey: "<anon-key>"
)

Protect the table in SQL, so the app needs no user filters:

create table public.todos (
  id bigint generated always as identity primary key,
  user_id uuid not null default auth.uid() references auth.users on delete cascade,
  task text not null,
  is_complete boolean not null default false,
  created_at timestamptz not null default now()
);
alter table public.todos enable row level security;
create policy "own todos" on public.todos for all to authenticated
  using (user_id = auth.uid()) with check (user_id = auth.uid());

Query with Codable from a SwiftUI view model:

struct Todo: Codable, Identifiable {
  var id: Int?
  var task: String
  var isComplete: Bool = false
  enum CodingKeys: String, CodingKey { case id, task, isComplete = "is_complete" }
}

@MainActor @Observable final class TodoStore {
  var todos: [Todo] = []

  func load() async throws {
    todos = try await stitchdb.from("todos")
      .select("id, task, is_complete")
      .order("created_at", ascending: false)
      .execute().value
  }

  func add(_ task: String) async throws {
    let created: Todo = try await stitchdb.from("todos")
      .insert(Todo(task: task)).select().single().execute().value
    todos.insert(created, at: 0)
  }
}

Register for APNs and check purchases with the same client:

// AppDelegate: didRegisterForRemoteNotificationsWithDeviceToken
try await stitchdb.push.register(.apns(deviceToken, topics: ["news"]))

// After a StoreKit 2 purchase
let result = try await product.purchase()
if case .success(let verification) = result { try await stitchdb.purchases.sync(verification) }
if try await stitchdb.purchases.hasEntitlement("pro") { unlockPro() }

Push needs your APNs .p8 key uploaded once in Studio › Integrations › Push (push); purchases (from the Pro plan) are covered in in-app purchases. For sign-in, signInWithOAuth(provider:redirectTo:) opens an ASWebAuthenticationSession, or the hosted sign-in page gives you finished screens with signInWithHostedPage. The full walkthrough is in iOS backend for Swift apps.

Offline: the Swift SDK has the same offline client as the JavaScript one (client.offline(...)), which keeps chosen tables on the device and syncs writes later, with a conflict rule per table (offline sync).

#How to decide

1. Apple-only, mostly private per-user data? CloudKit.
2. Android from day one and document-shaped data? Firebase.
3. Relational data, SQL, and you need US or Asian regions? Supabase.
4. Your company runs on AWS? Amplify.
5. Relational data plus push, purchases and app services in one project, EU hosting fine? StitchDB.

Whatever you choose, keep two things out of the app: privileged keys (they bypass your rules) and purchase decisions (verify on the server).

#FAQ

#What is the best free backend for an iOS app?

Firebase, Supabase and StitchDB all have free tiers with 50,000 monthly active users for auth as of November 2026. Firebase limits Firestore reads and writes per day; Supabase pauses inactive free projects; StitchDB's Free plan includes 10,000 push notifications a month.

#Is CloudKit enough for a production app?

Yes, for Apple-only apps where users mainly see their own data. It gets harder when you need Android, cross-user queries or server-side logic.

#Can I use SwiftData with a Postgres backend?

SwiftData can be your local store, but sync to Postgres is your code. If you want sync handled for you, use the backend's own offline client or CloudKit.

#Do I need a server for StoreKit 2?

You can check transactions on the device, but server-side checks stop users from unlocking features by editing the app, and let your web or Android app see the same entitlements.

Start your SwiftUI backend: create a free StitchDB project and follow the Swift SDK guide.