# Package Overview > Understand the public Collaboration SDK packages for Core, History, Thread Comment, Worktree, and Office Exchange. - Human documentation: [https://office.univer.ai/collaboration/packages](https://office.univer.ai/collaboration/packages) - Agent Markdown: [https://office.univer.ai/collaboration/packages.md](https://office.univer.ai/collaboration/packages.md) - Language: `en` - Source file: `content/docs/collaboration/packages.mdx` - Upstream source: [https://github.com/dream-num/office.univer.ai/blob/main/content/docs/collaboration/packages.mdx](https://github.com/dream-num/office.univer.ai/blob/main/content/docs/collaboration/packages.mdx) --- This page is a package selection map for the Collaboration SDK. Assemble Core Collaboration first, then add extension modules required by the product. You do not need to install every package. ## Core Collaboration Core Collaboration provides the main path for browser collaboration, server protocol handling, OT, revisions, and persistence. | Runtime | Package | Primary responsibility | | -------- | -------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------- | | Browser | [`@univerjs-pro/collaboration`](https://www.npmjs.com/package/@univerjs-pro/collaboration) | Registers foundational browser collaboration capabilities | | Browser | [`@univerjs-pro/collaboration-client`](https://www.npmjs.com/package/@univerjs-pro/collaboration-client) | Loads Units, submits changesets, and maintains realtime synchronization | | Browser | [`@univerjs-pro/collaboration-client-ui`](https://www.npmjs.com/package/@univerjs-pro/collaboration-client-ui) | Provides collaboration status UI and styles | | Server | [`@univerjs-pro/collaboration-transport-node`](https://www.npmjs.com/package/@univerjs-pro/collaboration-transport-node) | Receives Node.js HTTP and WebSocket traffic | | Server | [`@univerjs-pro/collaboration-endpoint`](https://www.npmjs.com/package/@univerjs-pro/collaboration-endpoint) | Implements the Client protocol, Sessions, Rooms, and Presence | | Server | [`@univerjs-pro/collaboration-service`](https://www.npmjs.com/package/@univerjs-pro/collaboration-service) | Manages Units, OT, revisions, and core Service APIs | | Database | [`@univerjs-pro/collaboration-database-memory`](https://www.npmjs.com/package/@univerjs-pro/collaboration-database-memory) | In-process storage for tests, examples, and temporary development | | Database | [`@univerjs-pro/collaboration-database-sqlite`](https://www.npmjs.com/package/@univerjs-pro/collaboration-database-sqlite) | SQLite persistence for development, testing, local, and small-scale use | A Core Server needs Transport, Endpoint, Service, and one Database Adapter. Memory and SQLite implement the same Adapter contract; applications normally select one. ## History History builds a version-history index from Core Unit creation and changeset commit Events. | Runtime | Package | Primary responsibility | | -------- | ------------------------------------------------------------------------------------------------------------------------------------------ | ---------------------------------------------------- | | Browser | Reuses Core Client/UI | Displays and reads history entries | | Server | [`@univerjs-pro/collaboration-history-service`](https://www.npmjs.com/package/@univerjs-pro/collaboration-history-service) | Builds and queries the history index | | Server | [`@univerjs-pro/collaboration-history-endpoint`](https://www.npmjs.com/package/@univerjs-pro/collaboration-history-endpoint) | Provides History protocol capabilities to the Client | | Database | [`@univerjs-pro/collaboration-history-database-sqlite`](https://www.npmjs.com/package/@univerjs-pro/collaboration-history-database-sqlite) | Stores the derived History index | History data is a rebuildable derived index. Core changesets remain authoritative for Unit content. ## Thread Comment Thread Comment manages comment bodies, replies, and solved state for Sheets and Docs. | Runtime | Package | Primary responsibility | | -------- | ------------------------------------------------------------------------------------------------------------------------------------------ | ---------------------------------------------------------------------- | | Browser | Reuses Core Collaboration packages | Uses Comment Client and UI capabilities | | Server | [`@univerjs-pro/collaboration-comment-service`](https://www.npmjs.com/package/@univerjs-pro/collaboration-comment-service) | Manages comment operations and the `commentCommitted` Event | | Server | [`@univerjs-pro/collaboration-comment-endpoint`](https://www.npmjs.com/package/@univerjs-pro/collaboration-comment-endpoint) | Provides the comment protocol and publishes updates through Unit Rooms | | Database | [`@univerjs-pro/collaboration-comment-database-memory`](https://www.npmjs.com/package/@univerjs-pro/collaboration-comment-database-memory) | In-process comment storage | | Database | [`@univerjs-pro/collaboration-comment-database-sqlite`](https://www.npmjs.com/package/@univerjs-pro/collaboration-comment-database-sqlite) | SQLite comment persistence | The Comment Adapter stores comment data. Anchors that move with content remain part of Core snapshots and changesets. ## Worktree Worktree provides isolated drafts, status transitions, and per-Unit merge. | Runtime | Package | Primary responsibility | | -------- | -------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------- | | Browser | [`@univerjs-pro/collaboration-worktree-client`](https://www.npmjs.com/package/@univerjs-pro/collaboration-worktree-client) | Connects Worktree draft, status, and merge capabilities | | Server | [`@univerjs-pro/collaboration-worktree-service`](https://www.npmjs.com/package/@univerjs-pro/collaboration-worktree-service) | Manages draft changesets, status, and merge | | Server | [`@univerjs-pro/collaboration-worktree-endpoint`](https://www.npmjs.com/package/@univerjs-pro/collaboration-worktree-endpoint) | Provides protocol capabilities to Worktree Client | | Database | [`@univerjs-pro/collaboration-worktree-database-memory`](https://www.npmjs.com/package/@univerjs-pro/collaboration-worktree-database-memory) | In-process Worktree storage | | Database | [`@univerjs-pro/collaboration-worktree-database-sqlite`](https://www.npmjs.com/package/@univerjs-pro/collaboration-worktree-database-sqlite) | SQLite Worktree persistence | Worktree Service eventually merges into the trunk through Core Service, so Middleware must be configured for both Service boundaries. ## Office Exchange Office Exchange is an application workflow combining file conversion with Collaboration Service. It has no independent collaboration Database Adapter. | Runtime | Package | Primary responsibility | | ------- | ------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------- | | Browser | [`@univerjs-pro/exchange-client`](https://www.npmjs.com/package/@univerjs-pro/exchange-client) | Provides foundational browser file-exchange capabilities | | Browser | [`@univerjs-pro/sheets-exchange-client`](https://www.npmjs.com/package/@univerjs-pro/sheets-exchange-client) | Provides Sheet file import and export | | Server | [`@univerjs-pro/exchange-node`](https://www.npmjs.com/package/@univerjs-pro/exchange-node) | Converts Office files and Univer data in Node.js | For import, the application passes converted data to `createUnitFromSnapshot()`. For export, it reads a confirmed Unit revision through Core Service. Files, tasks, and business APIs remain under application control. ## Selection rules 1. Start with the Core packages from [Quick Start](https://office.univer.ai/collaboration/quick-start.md). 2. Select one Core Database Adapter from Memory, SQLite, or a custom implementation. 3. Install only the extension-module packages used by the product. 4. Create separate Adapters for each module even when they share one SQLite file. See [Collaboration extension modules](https://office.univer.ai/collaboration/extensions.md) for module relationships and the [examples index](https://office.univer.ai/collaboration/examples.md) for runnable assemblies.