Collections

Collections offers xAI API users a robust set of tools and methods to seamlessly integrate their enterprise requirements and internal knowledge bases with the xAI API. Whether you're building a RAG application or need to search across large document sets, Collections provides the infrastructure to manage and query your content.

There are two entities that users can create within the Collections service:

• File — A single entity of a user-uploaded file.
• Collection — A group of files linked together, with an embedding index for efficient retrieval.
  • When you create a collection you have the option to automatically generate embeddings for any files uploaded to that collection. You can then perform semantic search across files in multiple collections.
  • A single file can belong to multiple collections but must be part of at least one collection.

With Collections, you can:

• Create collections to organize your documents
• Upload documents in various formats (HTML, PDF, text, etc.)
• Search semantically across your documents using natural language queries
• Configure chunking and embeddings to optimize retrieval
• Manage documents by listing, updating, and deleting them

Choose how you want to work with Collections:

• Using the Console → - Create collections and upload documents through the xAI Console interface
• Using the API → - Programmatically manage collections with the SDK and REST API

Collections support metadata fields — structured attributes you can attach to documents for enhanced retrieval and data integrity:

• Filtered retrieval — Narrow search results to documents matching specific criteria (e.g., author="Sandra Kim")
• Contextual embeddings — Inject metadata into chunks to improve retrieval accuracy (e.g., prepending document title to each chunk)
• Data integrity constraints — Enforce required fields or uniqueness across documents

When creating a collection, define metadata fields with options like required, unique, and inject_into_chunk to control how metadata is validated and used during search.

Learn more about metadata fields →

To be able to upload files and add to a collections you must have credits in your account.

Maximum file size: 100MB
Maximum number of files: 100,000 files uploaded globally.
Maximum total size: 100GB

Please contact us to increase any of these limits.

We do not use user data stored on Collections for model training purposes.

While we support any UTF-8 encoded text file, we also have special file conversion and chunking techniques for certain MIME types.

The following would be a non-exhaustive list for the MIME types that we support: