App development agency for iOS and Android

Native apps, each tailored to iPhone and Android. AI builds them, and an AI from a different company reviews them.

Work that usually takes three months, done within two weeks.

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Apps we build

Eigen is a mobile app development agency. We build iPhone apps in Swift and Android apps in Kotlin with Jetpack Compose. Each one is a native app made for its platform.

Automated checks grade the work first, starting with whether the app builds at all. Then a reviewer AI from a different company looks at the result and the evidence. No evidence, not done.

At the end you get the app install file and all the source code. Install it, try it yourself, and confirm.

  • iPhone apps

    Native iOS apps built in Swift.

  • Android apps

    Native Android apps built in Kotlin and Jetpack Compose.

  • Apps with subscriptions and payments

    Cask Strength has a taste quiz, a monthly subscription, and pickup by QR code. We also built the tablet screen its partner stores use.

  • Apps built around maps and location

    Waybite pins restaurants near a travel plan on a map. During the trip, it shows picks near where you are.

You do three things

Give us the idea, approve the plan, and try it yourself at the end. Eigen handles the rest.

  1. You

    Idea

    Send an idea, a spec, or designs. We tell you what is missing first.

  2. Planning AI, your approval

    Plan

    We write the task list, the order, and the acceptance criteria. You approve, and we start.

  3. Builder AI

    Build

    Tasks are built one by one. Tasks that don’t depend on each other are built at the same time.

  4. Automated checks

    Grade

    Code grades the work. If it fails, it goes back to the build.

  5. Reviewer AI, other company

    Review

    It looks only at the result and the evidence, then decides pass or fail.

  6. You

    Final check

    You try it and confirm. If something needs fixing, tell us right away.

Why you can trust the result

  • Done only when the automated checks pass

    Code checks whether the app builds, whether it follows the code rules, and whether the features work. One failure and the task can’t be marked complete.

  • Reviewed by an AI from a different company

    The reviewer AI is a model from a different company. It never sees the builder’s explanations, only the result and the evidence.

  • No hollow demos

    Fake data, switched-off features, and screens that only look real all fail the reviewer AI.

  • Follow progress on a live board

    Each task shows its status, the number of attempts, and the number of failing checks as they change. It’s there at night and on weekends too.

See what we’ve built

Frequently asked questions

Can you build both the iPhone and the Android app?

Yes. We build a native app for each: Swift for iPhone, Kotlin and Jetpack Compose for Android. If you want one codebase for both, we build cross-platform apps too.

Do I need an app spec?

No. An idea is enough to start. The planning AI turns the gaps into questions and suggests defaults. You only choose.

Can I trust an outside team with my app?

You don’t have to ask where things stand: you watch your own live board. For each task, the status, the number of attempts, and the number of failing checks update at once. The AI that builds and the AI that reviews are models from different companies, and the reviewer looks only at the result and the evidence. At the end, you install the app and try it yourself.

Will new features break the ones already built?

Each time a task is merged, every feature finished before it is checked again. If even one check fails, that task can’t be marked complete.

Are the keys for login and payments safe?

The spec lists names only. Real values are stored separately and used only while building and checking. They never appear in the code or the reports. A secrets check verifies this.

Have an app in mind?

Send us an idea or a spec. We start by sorting out what’s missing.

Contact us See other work