Qianji - System Architecture

Qianji is an offline system architecture knowledge library for software developers, architects, and computer technology learners.

The catalog covers 9 technical domains, 59 topics, and 287 Chinese-language system architecture lectures with 2,616 illustrations. Full text is available through Lecture 255; the remaining 32 upcoming lectures are listed by title and will be released as the series continues. Articles and images are bundled with the app, so no account or content download is required for offline reading, searching, or viewing images.

The interface supports Simplified Chinese, Traditional Chinese, English, Japanese, and Korean. Article titles and bodies are currently provided in their original Simplified Chinese and are not automatically translated.

Core features:

- Two ways to explore: browse the structured catalog or use the architecture map to understand relationships between topics
- Native reading: articles, code, tables, and images are rendered with native UI components, without WebView
- Offline full-text search: search titles, summaries, and article bodies entirely on device
- Read aloud: listen to articles with installed offline system voices, with lock-screen playback and speed control
- Reading management: bookmark articles and automatically preserve reading progress
- Study annotations: add color highlights and notes to article paragraphs
- Article sharing: create compact poster cards or long images with article text, or copy ready-to-share text
- Appearance controls: light, dark, and system themes
- Local-first storage: bookmarks, progress, highlights, notes, and preferences remain on your device

The "DNS and Domain Name Resolution" topic is available as a free preview. Other published content can be permanently unlocked with a single non-consumable in-app purchase. There is no subscription or automatic renewal, and previous purchases can be restored.

Qianji has no account system and includes no advertising, analytics, or tracking SDKs. Apart from Google Play requests for product and purchase status, reading and personal data stay on the device.