Track and version objects

Track and version any JSON-serializable object in W&B Weave

This page explains how to publish, retrieve, delete, and reference versioned objects in W&B Weave. Use it when you need to track structured data such as datasets, models, or prompts across runs and over time.

Objects

An Object is versioned, serializable data. Weave automatically versions objects when they change and creates an immutable history. Objects include:

• Datasets: Collections of examples for evaluation
• Models: Configurations and parameters for your LLM logic
• Prompts: Versioned prompt templates

dataset = weave.Dataset(
    name="test-cases",
    rows=[
        {"input": "What is 2+2?", "expected": "4"},
        {"input": "What is the capital of France?", "expected": "Paris"},
    ]
)
weave.publish(dataset)

Publish an object

Weave’s serialization layer saves and versions objects.

Python

import weave
weave.init("your-team-name/your-project-name")
# Save a list, giving it the name 'cat-names'
weave.publish(['felix', 'jimbo', 'billie'], 'cat-names')

TypeScript

TypeScript publishing support is limited. Not all objects are supported.

import * as weave from 'weave'

const client = await weave.init("your-team-name/your-project-name")

// Save an array, giving it the name 'cat-names'
client.publish(['felix', 'jimbo', 'billie'], 'cat-names')

When you save an object with a name, Weave creates the first version of that object if it doesn’t exist.

Get an object back

After publishing, you can fetch a stored object using its reference.

Python

weave.publish() returns a Ref. Call .get() on any Ref to get the object back.

You can construct a ref and then fetch the object back.

weave.init("your-team-name/your-project-name")
cat_names = weave.ref('cat-names').get()

TypeScript

This feature isn't available in TypeScript yet.

Delete an object

If you no longer need a specific version of an object, you can remove it using its ref.

Python

To delete a version of an object, call .delete() on the object’s ref.

weave.init("your-team-name/your-project-name")
cat_names_ref = weave.ref('cat-names:v1')
cat_names_ref.delete()

Accessing a deleted object returns an error. Resolving an object that references a deleted object returns a DeletedRef in place of the deleted object.

TypeScript

This feature isn't available in TypeScript yet.

Construct object refs

Refs uniquely identify a stored object and version. The following sections describe the URI structure and the ways you can construct a ref.

In Weave, a fully qualified object ref URI looks like this:

weave:///[YOUR-TEAM-NAME]/[YOUR-PROJECT-NAME]/object/[OBJECT-NAME]:[OBJECT-VERSION]

• [YOUR-TEAM-NAME]: W&B entity (username or team name)
• [YOUR-PROJECT-NAME]: W&B project
• [OBJECT-NAME]: object name
• [OBJECT-VERSION]: either a version hash, a string like v0 or v1, or an alias like :latest. All objects have the :latest alias.

You can construct refs with a few different styles:

• weave.ref([NAME]): retrieves the :latest version of an object. Requires calling weave.init(...).
• weave.ref([NAME]:[VERSION]): retrieves the specified version of an object. Requires calling weave.init(...).
• weave.ref([FULLY-QUALIFIED-REF-URI]): retrieves the object located at the specified fully qualified object ref URI. Doesn’t require calling weave.init().