# Appollo41 — Full Site Brief > 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). This file expands on https://appollo41.com/llms.txt with detailed content from every main page of appollo41.com. ## What Appollo41 is Appollo41 is a Nostr and Bitcoin app development studio. Its positioning: "Nostr and Bitcoin apps. Shaped with you. Built to last." The studio builds native, multiplatform mobile apps and has shipped production software on the Nostr protocol and the Bitcoin and Lightning networks. The flagship credential: "We built Primal for Android, one of the most-used apps on the protocol." Headline credentials: - Built and shipped the Primal Android app, a popular Nostr client and one of the most-used apps on the protocol. - Builds and ships its own products on the App Store and Google Play, including Finlab and Yogamaster Meditations. - Delivered a non-custodial cross-platform Bitcoin and Lightning wallet and a NIP-46 cryptographic remote signer, both running in production. Based in Europe, GMT+2. ## How Appollo41 works Engineers stay in the lead. Appollo41 brings AI agents onto the team the same way it brings on developers: "Trained, not rented." Agents are onboarded with specialized skills and long-term memory and handle implementation work, while engineers shape the work, review every change, and own the result. As the site puts it: "The engineer is always in the lead." This approach lets the studio accelerate delivery while keeping its craft standards. ## Team and origin Appollo41 was founded in 2016 by Aleksandar Ilic. He built and taught a university mobile-development course from scratch, delivering live coding demos to students. When exceptional students came back looking for more work, and a client asked the studio to scale up, the pattern became clear: "The people who come to you already belong." The studio describes itself as "built from the students who came back for more." The founding philosophy: hiring the right people matters more than any recruitment process. "The classroom was the interview. Hiring came after." The team is kept deliberately small and senior, based in Europe (GMT+2), with low turnover and long-term commitment. What the studio looks for: strong fundamentals in computer science and platform internals, genuine passion for mobile development, and long-term commitment. ## Services The studio offers six services. **Nostr development.** "On Nostr since the beginning. We built Primal Android, one of the most-used clients on the protocol." Nostr clients and protocol-level work. **Bitcoin & Lightning integration.** Two approaches: embed wallet functionality directly in the app via Spark for in-app Lightning and on-chain support, or integrate external wallets through Nostr Wallet Connect (NWC). **Multiplatform mobile apps.** "One team, one codebase for business logic, native UI on both sides. Kotlin Multiplatform without the cross-platform jank." **Product discovery & MVP.** Helping teams determine which features are essential and which to defer, prioritizing value delivery within budget constraints. **KMP advisory.** Helping teams extract shared business logic into libraries while preserving native UI implementation across both platforms. **Team extension.** "Senior Kotlin engineers embedded in your team. Your tools, your process, our expertise." ### Engagement models - **Project-based:** fixed scope and pricing for MVPs and defined features. - **Monthly retainer:** ongoing development capacity with flexible scope. - **Team extension:** engineers integrated into the client's own team. ## 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). ## Industries served - Bitcoin, Lightning, and Nostr protocols - Finance & Analytics - Construction - Health & Wellness ## Portfolio and case studies ### Primal Android Nostr social client built from scratch, now the core of Primal's cross-platform mobile stack. Three years, active. Tags: Kotlin, Jetpack Compose, KMP, Nostr, Bitcoin, Android. Case study: https://appollo41.com/portfolio/primal-android Product: https://primal.net ### Primal Wallet Non-custodial Bitcoin and Lightning wallet shared across Android and iOS via Kotlin Multiplatform. Tags: KMP, Bitcoin, Lightning, NWC, Android, iOS. Case study: https://appollo41.com/portfolio/primal-wallet Product: https://primal.net ### Primal Signer NIP-46 cryptographic remote signer for Nostr, shared between Android and iOS. Tags: KMP, Nostr, NIP-46, Android, iOS. Case study: https://appollo41.com/portfolio/primal-signer Product: https://primal.net ### Finlab Finance tracking for individuals and businesses, on Android, iOS, and the web. Appollo41's own product. Tags: Kotlin, Compose Multiplatform, Android, iOS, Web, Fintech. Case study: https://appollo41.com/portfolio/finlab Product: https://finlab.rs ### Yogamaster Meditations Guided meditation video and training programs, on iOS and Android. Built end to end as a partner product. Tags: Kotlin, Compose Multiplatform, iOS, Android, Health & Wellness. Case study: https://appollo41.com/portfolio/yogamaster Product: https://jogamaster.com ### Capmo Offline-first Android app for the construction industry. Appollo41 contributed an embedded developer to Capmo's team. In 2022, Appollo41 embedded a developer in Capmo's engineering team, working day to day in their codebase and process on production feature work across the Android app. The app is offline-first by necessity: project data lives on the device so crews can document defects and tasks with no signal, then reconciles once a connection returns. The code shipped is part of the live Capmo app, used across the DACH region by construction firms including Vinci and Zech. Capmo has since grown to power 60,000+ construction projects and raised a $30M Series B from Bessemer Venture Partners. Tags: Team Extension, Kotlin, Android, Offline-first, Construction. Case study: https://appollo41.com/portfolio/capmo Product: https://capmo.com ### Vertt+ Technical audit and stabilization for a Swiss ride-hailing platform. In 2021, a Swiss ride-hailing startup was hitting critical production issues that prevented scaling, and the existing team could not identify the root causes. Appollo41 ran a comprehensive technical audit of the full-stack solution, identified critical architectural bottlenecks, resolved the problems, and stabilized the platform for continued development. This was a diagnostic and firefighting engagement, not a greenfield build. Vertt+ continues to operate in Zurich with plans for expansion. Tags: Technical Audit, Full-Stack, Performance. Case study: https://appollo41.com/portfolio/vertt Product: https://vertt.ch ### Inspirock Appollo41 provided a developer for algorithm optimization at Inspirock, a travel planning platform used by 25M+ travelers annually. Inspirock was later acquired by Klarna. ## How to engage - **Book a call:** https://calendly.com/appollo41/getting-to-know — a 30-minute call with the founder. No sales script, just a real conversation. - **Email:** hello@appollo41.com - **GitHub:** https://github.com/Appollo41 ## Key pages - Homepage: https://appollo41.com/ - About: https://appollo41.com/about - Services: https://appollo41.com/services - Portfolio: https://appollo41.com/portfolio