LINE App Unifies Group Chats

LINE previously operated Rooms for one-off conversations and Groups for long-term use, separately. Rooms started right away without a name and joined immediately upon invitation, while Groups had names, required invitation acceptance, and offered features like Album and Note.

This difference created problems for both user experience and operational efficiency. General users had difficulty understanding the functional differences between Rooms and Groups, so whenever they needed a certain feature, they would create a new Group, and the conversation history of the existing Room would end up being discarded. At the same time, new Rooms with the same member combinations kept being created repeatedly, unnecessarily piling up server and client resources.

To solve this, Rooms and Groups were unified into Group Chat. After the integration, only the joining method differs, while the API and Storage have been merged into the same spec, and all newly created chats become Group Chat.

The key changes are as follows.

• API integration: A new Group Chat API was created and transitioned in parallel with the existing Group API using dual read.
• Data migration: Existing Group data was migrated to Group Chat data in batches.
• Unified joining method: When creating a new chat, users can now choose between joining immediately or an accept/decline method.
• Existing chat hints: If an existing chat with the same members exists, a hint is shown when creating a new chat to reduce duplicate creation.
• Feature expansion: Since the new model is Group-based, future features can be applied to all chats going forward.

Currently, all chats created in the latest version of LINE are Group Chat, and the goal going forward is to migrate even the existing Rooms to the new model to provide the same features across all chats. As a result of this project, the ratio of newly created chats with the same member combination dropped from 15% to 0.78%.