Inside the WeChat HarmonyOS Rewrite: Challenges & Insights

01

On July 3, Tencent’s official "鹅厂黑板报" reported new features and progress of the WeChat HarmonyOS version.

It was highlighted that because of HarmonyOS’s unique architecture, years of accumulated WeChat functionality cannot be directly migrated and must be rewritten from the ground up.

Tencent also produced a podcast inviting three members of the WeChat HarmonyOS adaptation team to discuss the large‑scale refactoring’s technical challenges, product trade‑offs, and collaboration mechanisms.

anqi – Head of basic features for the HarmonyOS mobile version

zuogang – Head of basic features for the HarmonyOS desktop version

Little Jiang – WeChat public‑relations team

When discussing the difficulty of developing on HarmonyOS, the guests explained that the native approach means abandoning the open‑source Android framework and building an entirely new framework, requiring a complete rewrite of WeChat.

anqi noted that WeChat’s emphasis on user experience means many components must be built natively from scratch, and the codebase accumulated over more than a decade lacks sufficient documentation, forcing developers to reverse‑engineer the old code.

They also mentioned that Huawei’s HarmonyOS is still in a rapid‑iteration phase, with frequent API changes—sometimes two versions per month—making adaptation labor‑intensive, especially when dealing with breaking upgrades.

02

What is it like to develop WeChat from scratch?

Interested readers can listen to the podcast for detailed insights.

Podcast Outline

Part 1 (2:14) – What is the WeChat HarmonyOS version?

2:30 – Why build a HarmonyOS version from the ground up?

3:42 – Previous cross‑platform development experience of the team

Part 2 (9:55) – Challenges of migrating WeChat to HarmonyOS

08:38 – Technical foundation: WeChat’s self‑developed cross‑platform kernel "Alita"

10:28 – Core modules like chat and Moments must be rebuilt

13:27 – Specific difficulties faced by mobile and desktop teams

19:36 – How the WeChat and Huawei teams collaborate efficiently

Part 3 (23:59) – Questions from HarmonyOS users

24:13 – Why is the development pace slower than expected?

27:48 – Why were download quotas limited at launch?

38:19 – How does the team handle widespread criticism?

41:55 – What will the future experience of WeChat HarmonyOS be like?

(Reference: Tencent Blackboard, Cloud Headlines)