---
title: "Obj Create"
method: POST
path: "/obj/create"
tags: ["Objects"]
---

# Obj Create

`POST /obj/create`

## Request

- Base URL: `https://trace.wandb.ai` (the document declares no server; this is the origin it was published from)
- URL: `https://trace.wandb.ai/obj/create`
- Auth: none declared

## Request body

- ObjCreateReq
  - `obj` ObjSchemaForInsert, required
    - `project_id` string, required
    - `object_id` string, required
    - `val` unknown, required
    - `builtin_object_class` string, nullable
    - `set_base_object_class` string, nullable
    - `expected_digest` string, nullable: Client-computed digest for server-side validation. If provided, the server will verify it matches the server-computed digest.
    - `wb_user_id` string, nullable: Do not set directly. Server will automatically populate this field.

## Response `200`

Successful Response

- ObjCreateRes
  - `digest` string, required
  - `object_id` string, nullable

## Other responses

- `422`: Validation Error

## Changes

- **2026-10-16** `dd89fadfe4e4`: 4 info
  - the endpoint scheme security `HTTPBasic` was removed from the API
  - added the new optional request property `obj/expected_digest`
  - added the optional property `detail/items/ctx` to the response with the `422` status
  - added the optional property `detail/items/input` to the response with the `422` status
- **2025-11-14** `b6cf2a1c4dac`: 2 breaking
  - the response property `object_id` became optional for the status `200`
  - response property `object_id` list-of-types was widened by adding types `null` to media type `application/json` of response `200`
- **2025-11-14** `b1962be94f75`: 2 info
  - the response property `object_id` became required for the status `200`
  - response property `object_id` list-of-types was narrowed by removing types `null` from media type `application/json` of response `200`
- **2025-11-13** `148dfd663d45`: 2 breaking
  - the response property `object_id` became optional for the status `200`
  - response property `object_id` list-of-types was widened by adding types `null` to media type `application/json` of response `200`
- **2025-11-13** `b1962be94f75`: 2 info
  - the response property `object_id` became required for the status `200`
  - response property `object_id` list-of-types was narrowed by removing types `null` from media type `application/json` of response `200`

[Operation history](https://skmtc.dev/wandb/apis/weights-biases-weave-stainless-api/changes/obj/create/post.md)

---

[API](https://skmtc.dev/wandb/apis/weights-biases-weave-stainless-api.md) - [All operations](https://skmtc.dev/wandb/apis/weights-biases-weave-stainless-api/llms.txt) - [OpenAPI document](https://skmtc.dev/wandb/apis/weights-biases-weave-stainless-api/revisions/f7643c49bf2e?raw)