Build a SaaS plus mobile app

One product, two apps

Customers sign in once and see the same data on the laptop and on the phone. Think of a coaching platform where coaches work in the browser and clients use the phone, or a field service tool with a dashboard in the office and a checklist app on site.

This setup has more moving parts than a single app, so it pays to decide early which parts live where. The browser side often handles setup, reports and billing. The phone side handles quick daily actions, notifications and offline use. Compare it with a plain SaaS and a plain mobile app to see what you really need.

The shared back end is the foundation

Both apps talk to the same APIi. If that layer is clean, a second app is mostly screens. If it is not, every feature is built twice.

• One login system for both apps, for example Supabasei or Firebasei.
• One database with permission rules, such as Row Level Securityi.
• One billing setup. If people can buy inside the phone app, the store billing rules of Apple and Google may apply, so ask your developer to check them for your case.
• Push notificationsi sent from the back end.

Typical technologies

A popular combination is Next.jsi for the browser and React Nativei with Expo for the phone, because both use TypeScript and can share types and logic. Flutteri or native Swifti and Kotlini work as well. Find My Stack can suggest a fit for your idea.

An example plan in milestones

Many teams ship the browser app first and the phone app second. Each milestone is funded before work starts and runs 1, 2, 3, 4, 6 or 8 weeks. Milestones are from 50 to 2,000 each in your project currency.

1. For example, weeks 1 to 3, shared base: data model, login, permissions, API and a first deploy.
2. For example, weeks 4 to 7, browser app: the core workflow, account settings and the plan and billing pages.
3. For example, weeks 8 to 11, phone app: sign in, the three or four actions people do daily, notifications, a test build for a small group.
4. For example, weeks 12 to 13, release: store submission, production monitoring, support emails and a handover note.

The weeks are for illustration. Developers set the length of each milestone in their proposal, and each real milestone runs 1, 2, 3, 4, 6 or 8 weeks. It is normal to hire one developer for the whole project. You can also start with one and add a second for the phone app later, as long as the API is documented.

What belongs in the project description

• Which tasks happen in the browser and which on the phone, in a simple table or list.
• Whether the phone app must work offline and what must sync.
• Who pays and where: on your website, in the app stores or both.
• The roles in the product, for example admin, member and guest.
• Platforms for the phone app and the browsers you must support.
• Which version ships first, and what the second can wait for.

How to recognise a suitable developer

Look for someone who has built both a web back end and a published phone app, or a pair of developers who say clearly who owns the API. Ask how they keep the two apps from drifting apart, how updates reach old app versions and how they test sign in on a real phone.

Each proposal has a match scorei. A developer needs at least 40 to apply, and 80 or more earns a Top match badge. Technologies are listed as Expert in (up to 6) or Also works with, which tells you how deep the experience goes. Developers are independent professionals, not our employees.