# Appollo41

> Appollo41 is a Nostr and Bitcoin app studio. We build native, multiplatform mobile apps with Kotlin Multiplatform, and we built the Primal Android app, one of the most-used clients on the Nostr protocol. Based in Europe (GMT+2).

Appollo41 builds Nostr and Bitcoin apps, shaped with the client and built to last. The studio shipped Primal for Android, a non-custodial Bitcoin and Lightning wallet, and a NIP-46 cryptographic remote signer, all running in production across Android and iOS. It also builds and ships its own products on the App Store and Google Play, including Finlab (finance tracking) and Yogamaster Meditations.

Founded in 2016 by Aleksandar Ilic, who built and taught a university mobile-development course from scratch. The team grew from the standout students who came back for more work: "The classroom was the interview. Hiring came after." Today Appollo41 is a small, deliberately senior team based in Europe (GMT+2). Engineers stay in the lead and bring AI agents onto the team the same way they bring on developers: trained, not rented.

Services offered:

- Nostr development: Nostr clients and protocol work. On Nostr since the beginning; built Primal Android, one of the most-used clients on the protocol.
- Bitcoin & Lightning integration: in-app Lightning and on-chain wallet functionality via Spark, or external wallets through Nostr Wallet Connect (NWC).
- Multiplatform mobile apps: one team, one codebase for business logic, native UI on Android and iOS. Kotlin Multiplatform without the cross-platform jank.
- Product discovery & MVP: decide what to build first and ship value within budget.
- KMP advisory: extract shared business logic into Kotlin Multiplatform libraries while keeping native UI on both platforms.
- Team extension: senior Kotlin engineers embedded in your team, working with your tools and your process.

Technology stack:

- Kotlin Multiplatform: shared business logic across Android and iOS.
- Jetpack Compose: native Android UI.
- SwiftUI: native iOS UI when a full native feel is required.
- Nostr: protocol work and clients, including NIP-46 remote signing.
- Bitcoin and Lightning: on-chain and Lightning integration via Spark, plus Nostr Wallet Connect (NWC).

Engagement models: project-based (fixed scope and pricing), monthly retainer (ongoing capacity, flexible scope), and team extension (engineers embedded in client teams).

## Portfolio

- [Primal Android](https://appollo41.com/portfolio/primal-android): Nostr social client built from scratch, now the core of Primal's cross-platform mobile stack.
- [Primal Wallet](https://appollo41.com/portfolio/primal-wallet): Non-custodial Bitcoin and Lightning wallet shared across Android and iOS via Kotlin Multiplatform.
- [Primal Signer](https://appollo41.com/portfolio/primal-signer): NIP-46 cryptographic remote signer for Nostr, shared between Android and iOS.
- [Finlab](https://appollo41.com/portfolio/finlab): Finance tracking for individuals and businesses on Android, iOS, and web. Appollo41's own product.
- [Yogamaster Meditations](https://appollo41.com/portfolio/yogamaster): Guided meditation video and training programs on iOS and Android.
- [Capmo](https://appollo41.com/portfolio/capmo): Offline-first Android app for the construction industry, delivered as an embedded developer on Capmo's team.
- [Vertt+](https://appollo41.com/portfolio/vertt): Technical audit and stabilization for a Swiss ride-hailing platform.

## Key pages

- [Homepage](https://appollo41.com/): What Appollo41 is and the work it leads with.
- [About](https://appollo41.com/about): Founder story, the team, and how Appollo41 works with AI agents.
- [Services](https://appollo41.com/services): Full list of services, tech stack, and engagement models.
- [Portfolio](https://appollo41.com/portfolio): All case studies.

## Contact

- [Book a call](https://calendly.com/appollo41/getting-to-know): 30-minute call with the founder. No sales script, just a real conversation.
- [Email](mailto:hello@appollo41.com): Reach the studio at hello@appollo41.com.
- [GitHub](https://github.com/Appollo41): Appollo41 on GitHub.

## Optional

- [llms-full.txt](https://appollo41.com/llms-full.txt): Detailed version of this file with full content from every main page.