Android and iOS apps can share much of their business logic while keeping separate implementations for platform features. Shared development is worth considering when people on both systems complete similar tasks. Separate development becomes a candidate when interfaces or device requirements differ substantially, or when you already have working apps and teams that maintain them.
Base the decision on the same feature list and a trial of the least certain integration. If you are still deciding whether an installed app is needed, start with our PWA versus native app comparison. Here, the starting decision has been made: the product needs to exist on Android and iOS, and you are choosing how to develop it.
What does one app for two platforms mean?
“One app” usually describes a shared product and some shared code. You still prepare the appropriate Android and iOS releases. The server can also be shared when the mobile apps themselves are developed separately.
For example, a rule for calculating a total or displaying an order may be shared. Connecting a particular device may require separate code. Flutter's documentation describes platform channels for connecting to Android and iOS code. React Native supports the Platform module and separate platform files. These mechanisms allow shared development to include distinct implementations.
Ask the proposal to specify what will be shared, what will be developed separately and who will maintain each part. The technology name alone does not describe the scope.
Which features determine the approach?
Write down what the user does and which device they use before choosing a framework. Suppose a distributor needs an app for receiving goods: a worker opens a delivery, scans items and confirms quantities. This is a hypothetical planning example, with no completed trial or confirmed support for a particular scanner.
Scroll the table sideways to see all columns.
| Feature | Potential shared work | What to check on each platform | Evidence before deciding |
|---|---|---|---|
| Delivery list and quantity entry | Data, business rules and parts of the interface. | Keyboard, navigation and layout on the agreed devices. | A user completes the same task in both versions. |
| Reading an item code with the camera | Processing the code and checking the item. | The chosen library, device and permissions needed. | Reading the agreed samples and handling unavailable access. |
| External scanner | The workflow after a code is received. | The exact model, connection method and supported SDK version. | Scanning, connection loss and reconnection on both platforms. |
| Finishing a submission after leaving the app | Order status and rules for retrying a request. | The permitted background mechanism and interruptions. | The recorded outcome of the same action under agreed conditions. |
| Different workflows for two user groups | Only the rules that are actually the same. | Whether the same screen suits both groups' work. | Approved prototypes and separate acceptance criteria. |
Keep two records for each row, one for Android and one for iOS: device model, OS version, plugin or SDK version, trial date and outcome. Until a claim has been checked, mark it “not verified”. An unknown requirement recorded this way can be investigated before commissioning the whole app.
What does shared code leave to be checked?
A shared business rule does not establish that a feature works the same way on both devices. On Android, for example, an app needs to handle a user refusing or revoking a required permission. The official permission guidance describes requesting access when a feature is used and allowing the app to continue with an appropriate limitation.
Be precise about a requirement to “work in the background”. Android describes several task mechanisms, while Apple describes strategies where the system chooses when deferred work runs. Define what must finish and how the app informs the user when work is delayed or interrupted.
In our hypothetical goods-receiving app, confirming an order may use the same business rules. Connecting the scanner and handling the app moving into the background remain separate items to verify. For any plugin, check maintenance and supported versions, then include the actual device in the trial.
When should you consider separate development?
Consider separate apps when a requirement depends on features that differ substantially between platforms, or when each user group works differently. If an essential device has different manufacturer tools, investigate how much work connecting them would add to a shared codebase.
An existing product also deserves its own assessment. Before replacing two working apps, review code quality, team support and migration costs. Keeping the server or shared rules can have value without rewriting every screen.
Separate development needs an agreement on keeping features consistent too. When a calculation rule changes, who checks both versions, and how do you prevent users getting different results? Include that work in the maintenance plan.
What should a short technical trial demonstrate?
For the goods-receiving example, we would suggest testing the exact scanner before building the remaining screens. Prepare sample codes and expected results. The trial should cover these steps:
- Connect the agreed model and read a sample on physical Android and iOS devices.
- Record what happens when a required permission is refused or the connection drops, where those cases apply to the chosen connection method.
- Repeat the action after reconnecting and check that the result is neither lost nor entered twice.
- Keep the versions, steps and all outcomes, including failures, then identify what needs further work.
This is a proposed trial, not a report of one we have performed. Apple's documentation explains that a simulator does not reproduce every feature or the performance of a physical device. A simulator demonstration therefore does not confirm that the chosen scanner works in its intended setting.
Tests of business rules and tests of the whole user journey have different scopes, as the React Native testing guide describes. For acceptance of a feature, ask for evidence that the task can be completed on both agreed platforms.
How do you compare proposals and maintenance costs?
Both proposals should cover the same features, devices and acceptance criteria. Separate shared development from platform integrations, testing and release preparation. List the server and connections to business systems separately, so a difference in scope is visible in the comparison.
Ask each supplier to name unverified assumptions. For example, a quote might include an existing scanner plugin only if a technical trial confirms the required functions. If the trial fails, you need to know how you will decide between another device, additional development and changing the requirement.
For maintenance, agree dependency updates, checks against new OS versions and responsibility for publishing releases. A shared codebase can reduce duplicated work, but base the estimate on specific tasks. Our guide to business mobile app costs covers the wider budget and scope of a first version.
For the next step, read how a business app is published and who manages its store accounts. The release plan should distinguish build preparation, review and confirmed availability on Android and iOS.
What should you prepare for the development decision?
For a mobile app development discussion, prepare a description of one complete task, the devices people use and the functions they cannot work without. Include documentation for services or equipment that the app must connect to. If code already exists, identify who maintains it and which accounts or systems the business can access.
Send that description and the outstanding questions with your free project estimate request. We can use them to suggest what to check first, which parts may be shared and what to include separately in an Android and iOS proposal.