By Alpit Patel and the aibrevo team · October 31, 2026 · 5 min read
Do I Need a Backend for My App?
Quick answer
You need a backend if users log in, share data with other users or devices, pay, get push notifications, or if your team needs to see and manage what happens in the app. You can skip one only for a single-device app that stores everything locally, such as a calculator or an offline notes app. Most business apps need one.
Key takeaways
- If your app has accounts, data shared between users or devices, payments, push notifications or an admin view, it needs a backend.
- An app can run without one only if everything lives on a single device and nothing needs to be shared, synced or managed.
- Push notifications need a server: Firebase Cloud Messaging requires a trusted environment such as Cloud Functions or an app server to build and send messages.
- Backend-as-a-service tools have generous free tiers. Firebase's no-cost Spark plan includes 1 GiB of Firestore storage, 50,000 reads a day and 50,000 monthly active users for authentication.
- Apple requires apps that let users create an account to also let them delete it in the app, which needs a backend to carry out.
You need a backend if users log in, share data with other users or across devices, pay, get push notifications, or if your team needs to see and manage what happens in the app. You can skip it only when the app works entirely on one device with local data, such as a calculator, a timer or an offline notes app. Almost every business app needs one.
Checked on October 31, 2026. Technical facts come from Firebase’s documentation and pricing page and from Apple’s App Review Guidelines. Examples come from apps our team has built.
Does your app need a backend? A quick checklist
If you answer yes to any of these, plan for a backend.
| Question | If yes, the backend… |
|---|---|
| Do users create accounts or log in? | Stores accounts, handles sign-in and password resets, deletes accounts on request |
| Do users see each other’s content (posts, messages, listings)? | Stores shared data and decides who can see what |
| Should data sync across a user’s phone, tablet and web? | Keeps one source of truth |
| Do you send push notifications, emails or texts? | Builds and sends the messages |
| Do users pay, or do you pay people out? | Creates charges, receives payment webhooks, records orders |
| Does your team need to approve, edit or refund anything? | Powers the admin tools |
| Must the app talk to a CRM, booking system or database you already run? | Runs the integration securely, away from the phone |
| Do you need analytics on what users do? | Collects and stores events (often through a third-party service) |
If every answer is no, a backend-free app is possible. If you are not sure, your MVP probably needs at least sign-in and an admin view, which means a backend.
What does a backend actually do?
Think of the app as the shop window and the backend as the stockroom and the till. In a typical app it handles:
- Data. A database for users, content, orders and settings.
- Authentication. Sign-up, login, sessions and account deletion.
- Business rules. Pricing, permissions, matching and anything that must not be trusted to the phone.
- Messaging. Push notifications, email and SMS.
- Payments. Charges, refunds, payouts and payment provider webhooks.
- Integrations. Your CRM, calendar, maps, AI models or older internal systems.
- Admin. The tools your team uses to run the service.
Why do push notifications and account deletion need a server?
Two store-level reasons.
Push notifications. The phone receives notifications, but your side sends them. Firebase’s documentation describes an FCM implementation as needing “a trusted environment such as Cloud Functions for Firebase or an app server on which to build, target, and send messages” (Firebase Cloud Messaging, checked Oct 31, 2026). Apple’s push service works the same way, with your server sending each notification.
Account deletion. Apple’s App Review Guidelines (5.1.1(v)) say that if your app supports account creation, you must also offer account deletion within the app (Apple, checked Oct 31, 2026). Deleting an account means removing it from wherever it is stored, which is the backend.
Should you use a backend-as-a-service or a custom backend?
| Backend-as-a-service (for example Firebase) | Custom backend | |
|---|---|---|
| What it is | Hosted database, auth, storage and messaging you configure | Your own server code and database, hosted on a cloud provider |
| Speed to start | Fastest | Slower |
| Cost at small scale | Often free on the starter tier | Hosting from the first day |
| Complex business rules | Possible with serverless functions | Natural fit |
| Many integrations or legacy systems | Gets awkward | Natural fit |
| Regulated data and audit needs | Depends on the provider’s compliance options | Full control |
| Lock-in | Tied to the provider’s data model | Portable |
| Fits | MVPs and standard consumer apps | Marketplaces, dispatch, regulated or integration-heavy apps |
Firebase’s no-cost Spark plan, as listed on its pricing page:
| Service | No-cost quota |
|---|---|
| Cloud Firestore storage | 1 GiB total |
| Firestore reads | 50,000 a day |
| Firestore writes | 20,000 a day |
| Firestore deletes | 20,000 a day |
| Authentication | Up to 50,000 monthly active users |
| Cloud Messaging (push) | No cost |
Source: Firebase pricing, checked Oct 31, 2026. Usage above these quotas needs the pay-as-you-go Blaze plan.
What do real app backends look like?
Three backends from our own builds, to show the range:
- Respond Central, an EMS dispatch app: structured transport requests, automatic routing to crews matched on vehicle type and certification, live status tracking and e-signatures at pickup. The backend is the product here. Request to confirmed crew dropped from 22 minutes to 3.
- GoHangars, a hangar marketplace: two user types, availability calendars, filters that match aircraft dimensions to hangar doors, and Stripe Connect payouts with platform fees.
- Papri, a Bengali publishing app: search that indexes Bengali text and transliterated queries, serialized chapters, and offline reading that syncs when the connection returns.
None of these could run on the phone alone. Each took 6 to 8 weeks to first release, backend included.
Can your CRM be part of the backend?
Often, yes. If your business already runs on a CRM, the app’s backend can create and update contacts, deals and bookings there, so your team works from one record. We connect apps to GoHighLevel, HubSpot, monday.com and Pipedrive as part of the build; see CRM integration services. The CRM rarely replaces the backend entirely, because apps need fast reads, permissions and logic a CRM API is not built for.
What does a backend cost over time?
Running costs scale with use: database reads, storage, bandwidth, and paid services such as email, SMS, maps and AI. Ask for an estimate at 1,000, 10,000 and 100,000 users before you build. The backend also needs upkeep: security patches, dependency updates and monitoring. Our page on app maintenance costs covers that, and how much it costs to build an app covers the build.
At aibrevo we scope and build the backend alongside the app so both ship together. Our mobile app development page shows how.
Sources
- Firebase, Pricing, checked Oct 31, 2026.
- Firebase, Firebase Cloud Messaging, checked Oct 31, 2026.
- Apple, App Review Guidelines, section 5.1.1(v), checked Oct 31, 2026.
- Our case studies: Respond Central, GoHangars, Papri.