Architecture

Cloud Phone is a remote browser designed to address the hardware limitations of feature phones. Its architecture consists of three main components:

Components

Client

The Client is a thin client integrated into feature phone firmware. It displays content using the proprietary Puffin Vector Graphics Language format. Unlike other remote browsers that transmit pixels or video streams, the Client uses vector graphic commands to render pages on the screen. It also sends user input events, such as key presses, for the server to process.

Server

The Server consists of high-performance systems built on the Chromium engine used by Google Chrome. Servers fetch and render HTML, CSS, and JavaScript to construct the document object model (DOM). The rendered output is converted to Puffin Vector Graphics Language and streamed to the Client. These servers are hosted in enterprise-grade data centers with high-speed connections to major internet backbones worldwide.

Web Apps

Web Apps, also known as “widgets,” are tested and distributed through the Cloud Phone Developer Program. These widgets are self-hosted applications executed on Cloud Phone servers and made accessible to millions of users globally. Using W3C Standard Web APIs, widgets deliver rich applications to some of the world’s most underserved communities.

Developer Takeaways

Cloud Phone simplifies app development using modern web standards, enabling instant access to millions of users worldwide.

New Opportunities

Cloud Phone provides access to a previously untapped market: budget feature phone users. Feature phone sales reach hundreds of millions of units annually, with many of the best-selling mobile phones being feature phones. Running on devices with as little as 16MB RAM and costing as little as $12 USD, Cloud Phone is well-positioned to connect the next billion users, addressing the needs of the 2.6 billion people still offline.

Minimal Refactoring Required

Cloud Phone leverages powerful Chromium-based servers to overcome budget hardware limitations. This minimizes the need for costly optimizations or refactoring. Most Progressive Web Apps (PWAs) require only minor adjustments to fit small screens and support keyboard navigation. Refer to the Cloud Phone Design Guide for advice on adapting web app design.

Always Up-to-Date

Cloud Phone servers are regularly updated to the latest Chromium versions, providing access to modern APIs without requiring developers to handle backwards compatibility. Unlike some Android or KaiOS devices that stop receiving updates to the operating system, browser engine, or root certificates shortly after launch, Cloud Phone servers ensures feature phone integration remains seamless and secure.

Limitations

While Cloud Phone supports a wide range of web apps and games, it has some limitations:

Real-Time Games

Performance may not meet expectations for reaction-based apps or games requiring high refresh rates. Since rendering occurs server-side, there is a minimum round-trip time (RTT) for each screen update. Under stable 4G connections, Cloud Phone achieves a peak frame rate of approximately 20 FPS. Frame rates may decrease under poor network conditions.

Unsupported APIs

Widgets cannot rely on hardware APIs unavailable in Cloud Phone, such as near field communication (NFC) or Bluetooth low energy (BLE). However, Cloud Phone continues to evolve, and updates on newly-supported APIs will be published on this site.