Build a mobile app with an independent developer
To build a mobile app, you describe the one job it does, choose between one shared codebase for iPhone and Android or two native apps, and split the work into small paid milestones. ErdiBuilds is an open marketplace where clients post app, SaaS, website and game projects, see which independent developers from the EU fit best based on what they have already built, and pay per milestone.
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What a mobile app project looks like
A mobile app is software people install from the App Store or Google Play and use on their phone. It can send push notifications, use the camera, location or Bluetooth, and keep working with a weak connection. That is why people choose an app over a website for things they use every day.
Common examples are habit and fitness trackers, booking apps for a local business, companion apps for a physical product, community apps, delivery and field service apps, and learning apps. Games have their own page: see mobile games. If your product also needs a browser version, read about a SaaS plus mobile app.
A good first version does one thing well. Every extra screen adds weeks and review time in the stores, so start with the moment people open the app for.
Typical technologies
The biggest choice is between one codebase for both phones and separate native apps. Most first versions use one codebase, because it keeps the work smaller and updates quicker. Find My Stack can suggest a stack from your answers.
- React Native with Expo is a popular choice, especially for teams that also build websites.
- Flutter gives very consistent visuals on both platforms.
- Swift and Kotlin suit apps that need deep device features or the newest platform functions.
- Supabase or Firebase often handle accounts and data, so no custom server is needed at the start.
- Push notifications and in-app purchases need extra setup, so mention them early.
An example plan in milestones
Every project differs, but a first version often follows this shape. 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.
| Topic | Example timing | What happens | What you can check |
|---|---|---|---|
| Phase 1: Design and setup | For example, weeks 1 to 2 | Screens for the main flow, project setup, test build on a real phone | Clickable screens and an app you can install for testing |
| Phase 2: Core flow | For example, weeks 3 to 6 | Sign in, the main feature, saving data, basic error handling | The core job works end to end on iPhone and Android |
| Phase 3: Extras | For example, weeks 7 to 8 | Push notifications, settings, empty states, analytics | A complete app for a closed test group |
| Phase 4: Store launch | For example, weeks 9 to 10 | Store listing, screenshots, privacy details, review and fixes | The app is live in the stores under your own accounts |
Phase 1: Design and setup
- Example timing
- For example, weeks 1 to 2
- What happens
- Screens for the main flow, project setup, test build on a real phone
- What you can check
- Clickable screens and an app you can install for testing
Phase 2: Core flow
- Example timing
- For example, weeks 3 to 6
- What happens
- Sign in, the main feature, saving data, basic error handling
- What you can check
- The core job works end to end on iPhone and Android
Phase 3: Extras
- Example timing
- For example, weeks 7 to 8
- What happens
- Push notifications, settings, empty states, analytics
- What you can check
- A complete app for a closed test group
Phase 4: Store launch
- Example timing
- For example, weeks 9 to 10
- What happens
- Store listing, screenshots, privacy details, review and fixes
- What you can check
- The app is live in the stores under your own accounts
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, so a phase may be one milestone or several.
What belongs in the project description
- The one job the app does and who uses it.
- Platforms: iPhone, Android or both, and the oldest versions you must support.
- The three to five screens that matter most. A sketch or a link to a similar app helps.
- Phone features you need: camera, location, notifications, offline use.
- Where data comes from: an existing system, a new backend or none.
- Who owns the store accounts. Using your own accounts keeps the app yours from day one.
- A preferred launch date and what can wait for version two.
How to write a project brief walks through this in more detail, and the project brief tool helps you draft one.
How to recognise a suitable developer
Look for proof of finished apps: store links, a live demo or a repository you can read. Ask which apps they published, how they handled store review and what they would cut from your first version. Developers are independent professionals, not our employees.
ErdiBuilds also gives every proposal a match score. A developer needs at least 40 to apply, and 80 or more earns a Top match badge. You see proposals sorted by score and can read why each one fits. Verified means an ErdiBuilds admin has reviewed the developer and approved the profile by hand.
For questions worth asking in a first chat, see questions to ask before hiring a developer.
Frequently asked questions
Should my app run on iPhone, Android or both?
Start where your first users are. If you are unsure, one shared codebase with React Native or Flutter lets you reach both. A developer can tell you if your features need a native app instead.
Link to this answerWho publishes the app in the stores?
Your developer can do the upload, but the Apple and Google developer accounts should be yours. That way the listing and the app stay with you. Unless both sides agree otherwise in writing on the platform, the rights to the result of a milestone pass to the client once that milestone is paid in full.
Link to this answerCan the stores reject my app?
Yes, reviews can ask for changes, for example on privacy texts or sign in. Plan a few days for it, and ask the developer to include review fixes in the last milestone.
Link to this answerHow do payments work?
Each milestone is funded before work starts and runs 1, 2, 3, 4, 6 or 8 weeks. You approve the delivery, and the funds are released after approval and a short holding period. If you do not respond, the milestone is approved automatically after 14 days.
Link to this answerCan I add features after launch?
Yes. Many projects ship a small first version and add features in new milestones, with the same developer or a different one. Ask for readable code in your own repository so that stays easy.
Link to this answerRelated pages
- Build a mobile game with a developerPlan a phone game: engines like Unity and Godot, a milestone plan from prototype to store release, what the brief needs and how to judge a developer.
- Build a SaaS plus mobile app with a developerPlan a subscription product with a browser app and a phone app on one shared back end: technologies, milestone order, brief and developer fit.
- Hire a React Native and Expo developerOne codebase for iPhone and Android: what React Native and Expo can do, what to ask a developer, example milestones and how matching works.
- Hire a Flutter developer for your appFlutter builds iPhone and Android apps from one codebase. See what it suits, what to ask a Flutter developer and how a project is planned.
- How Long Does It Take to Build an App?What decides how long an app, SaaS, website or game takes to build, with an example plan in weeks and tips for planning realistic milestones.
- Hire a Developer to Build Something NewTurn an idea into a working product. See how to prepare, how milestones structure the work and what to ask developers before you start.