How Taro’s Open‑Source HarmonyOS Version Boosts Cross‑Platform App Development

Taro on HarmonyOS – Open‑Source Framework Overview

At the Huawei Developer Conference 2025, the retail technology team presented the officially open‑sourced HarmonyOS version of the Taro framework, outlining its technical implementation, core optimizations, and main features.

Background

Since its open‑source launch in June 2018, Taro has grown from a mini‑program‑only solution to a mature cross‑framework supporting multiple front‑end libraries, UI kits, and build tools such as Webpack, Vite, and ESBuild, covering Web, iOS, Android, and HarmonyOS platforms.

Taro has amassed over 36,000 stars and nearly 5,000 forks on GitHub, driven by contributions from enterprises and individual developers.

Technical Architecture Evolution

Starting in 2022, Taro introduced a JSUI plugin for HarmonyOS, followed by an ETS‑based plugin in 2023 that greatly improved developer experience and performance. The latest 4.1 release adds a C‑API plugin, marking a major breakthrough in HarmonyOS support.

The team continues to optimize the C‑API plugin, focusing on multithreading and additional features before open‑sourcing the next iteration.

Multi‑Platform Development Challenges

Traditional multi‑platform development suffers from inconsistent syntax, divergent component APIs, and complex environments, leading to low code reuse and high maintenance costs. Taro solves this by providing a unified DSL, standardized component and API libraries, and W3C‑compliant styling, enabling developers to write once and run everywhere.

JD HarmonyOS Case Study

Using Taro on HarmonyOS, JD’s Harmony version achieves industry‑leading performance and stability for high‑complexity pages such as product detail views. The single‑thread C‑API architecture delivers native‑level speed for data‑intensive scenarios.

Rendering Layer Adaptation

React code is transformed into a virtual node tree via deep integration with the React Reconciler. The runtime maps this tree to Taro’s internal nodes, which are then converted into native ArkUI components, forming the final rendering tree on HarmonyOS.

Architecture Iteration

Both the ETS and C‑API solutions share a three‑layer node architecture: React → Taro → ArkUI. The C‑API version replaces declarative recursive construction with imperative node operations, moving style, layout, and event handling to a C++ layer, dramatically reducing cross‑language overhead and improving performance.

Cross‑Platform Development Standards

Taro is building a comprehensive cross‑platform standard that includes 26 UI components, 88 APIs, and 93 style rules based on W3C specifications. The standard is extensible, allowing seamless integration with existing component libraries and toolchains.

Performance Features

Key performance enhancements include:

Runtime Optimization: DOM, event handling, and style calculations are moved to C++, reducing JavaScript‑native communication overhead.

High‑Order Components: Native List and WaterFlow components are customized for virtual lists and waterfall flows.

Image Processing: Multi‑level caching and adaptive compression improve loading speed and memory usage.

Text & Canvas: PixelMap‑based text rendering and full Canvas API support enable rich graphics and data visualization.

Video Playback: AVPlayer integration provides low‑latency, multi‑format video support.

Ecosystem and Future Outlook

Beyond JD’s Harmony app, partners such as 58.com and PuPu Supermarket have adopted the solution. The roadmap includes open‑sourcing multithreading, expanding cross‑platform standards, migrating more core modules to C++, and fostering community contributions.

The open‑source C‑API plugin, though newly released, has already attracted many contributors. The team invites developers passionate about cross‑platform technology to join and help shape the next generation of Taro on HarmonyOS.