Kios: An iOS Reader for Self-Hosted Kobo/Calibre Libraries with Progress Sync
Kios is a new iOS reader that connects to self-hosted Kobo/Calibre libraries (like Grimmory or Calibre-Web) and syncs reading progress using the Kobo protocol. It also supports OPDS 1.2 and 2.0 with progress sync, plus kosync (the open-source sync protocol for Kobo devices).
Key Features
- Direct connection to self-hosted Kobo servers (Grimmory, Calibre-Web)
- Reading progress sync via the Kobo protocol
- OPDS 1.2 and 2.0 catalog support with progress sync
- kosync integration
- Built entirely with Claude Code (Opus 4.8 with 1M-token context window) by a first-time iOS developer
Kios is currently available via TestFlight: join the beta.
Behind the Build
The developer, an experienced software engineer but an iOS novice, used Claude Code extensively. They even had Claude write a "book" about iOS development to understand and review the generated code rather than blindly accept it. The toolkit included Claude Code with Opus 4.8's 1M-token window, plus the Superpowers skills and Matt Pocock's architecture skill to maintain code quality as the project grew.
If you self-host your ebooks and switch between a Kobo and an iPhone, Kios bridges that gap. The developer is actively seeking feedback on both functionality and UX.
📖 Read the full source: r/ClaudeAI
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