---
title: "Create a new asset"
method: POST
path: "/api/assets"
tags: ["file"]
---

# Create a new asset

`POST /api/assets`

Creates a new asset from a direct file upload (multipart/form-data) with associated metadata.

If an asset with the same hash already exists, returns the existing asset.

## Response `200`

Asset already existed for this user (deduplicated by content hash); the
existing asset is returned with created_new=false.

- AssetCreated — Response returned when a new asset is successfully created.
  - `created_at` string, date-time, required — Timestamp when the asset was created
  - `display_name` string, nullable — Display name of the asset. Mirrors name for backwards compatibility.
  - `file_path` string, nullable — Relative path in global-namespace-root form (e.g. "models/checkpoints/flux.safetensors")
  - `hash` string — Blake3 hash of the asset content.
  - `id` string, uuid, required — Unique identifier for the asset
  - `is_immutable` boolean — Whether this asset is immutable (cannot be modified or deleted)
  - `job_id` string, uuid, nullable — ID of the job that created this asset, if available
  - `last_access_time` string, date-time — Timestamp when the asset was last accessed
  - `metadata` object — System-managed metadata from download sources (HuggingFace, CivitAI, etc.) - read-only, not user-modifiable
  - `mime_type` string — MIME type of the asset
  - `name` string, required — Name of the asset file
  - `preview_id` string, uuid, nullable — ID of the preview asset if available
  - `preview_url` string, uri — URL for asset preview/thumbnail
  - `short_url` string, nullable — Durable, owner-gated short link to this asset's content (relative `/api/s/{id}` path). Stable across the underlying signed URL's expiry — resolving it re-mints a fresh signed URL on every request — so it is safe to persist or share into chat, unlike `preview_url`. Only the minting user can resolve it. Omitted when the short-link surface is disabled or the asset has no resolvable content hash.
  - `size` integer — Size of the asset in bytes
  - `tags` string[] — Tags associated with the asset
  - `updated_at` string, date-time, required — Timestamp when the asset was last updated
  - `user_metadata` object — Custom user metadata for the asset
  - `created_new` boolean, required — Whether this was a new asset creation (true) or returned existing (false)

## Other responses

- `201` — Asset created successfully (created_new=true)
- `400` — Invalid request (bad file, invalid content type, etc.)
- `401` — Unauthorized
- `413` — File too large
- `415` — Unsupported media type
- `500` — Internal server error

## Changes

- **2026-06-20** `8af4304e9fb0` — 2 info
  - added the optional property `allOf[#/components/schemas/Asset]/short_url` to the response with the `200` status
  - added the optional property `allOf[#/components/schemas/Asset]/short_url` to the response with the `201` status
- **2026-06-09** `84406063d958` — 1 breaking, 1 warning, 8 info
  - removed the media type `application/json` from the request body
  - removed the optional property `allOf[#/components/schemas/Asset]/asset_hash` from the response with the `201` status
  - api operation id `uploadAsset` removed and replaced with `createAsset`
  - added the new optional request property `hash`
  - …6 more
- **2026-06-03** `8560879e6188` — 8 breaking, 5 warning, 11 info
  - the request property `id` became not nullable (media type: multipart/form-data)
  - the request property `name` became required (media type: application/json)
  - the `tags` request property type/format changed from `string`/`` to `array`/`` (media type: multipart/form-data)
  - the `tags` request property type/format changed from `string`/`` to `array`/`` (media type: application/json)
  - …20 more
- **2026-05-22** `09a5075587c8` — 10 info
  - api operation id `createAsset` removed and replaced with `uploadAsset`
  - added the non-success response with the status `400`
  - added the non-success response with the status `401`
  - added the non-success response with the status `403`
  - …6 more
- …earlier changes not shown

[Full history](https://skmtc.dev/comfy-org/apis/comfyui-api/changes/api/assets/post.md)

---

[API](https://skmtc.dev/comfy-org/apis/comfyui-api.md) · [All operations](https://skmtc.dev/comfy-org/apis/comfyui-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/comfy-org/comfyui-api/revisions/8af4304e9fb0/schema)