> ## Documentation Index > Fetch the complete documentation index at: https://docs.comfy.org/llms.txt > Use this file to discover all available pages before exploring further. # Create asset reference from existing hash > Creates a new asset reference using an existing hash from cloud storage. This avoids re-uploading file content when the underlying data already exists, which is useful for large files or when referencing well-known assets. The user provides their own metadata and tags for the new reference. ## OpenAPI ````yaml /openapi-cloud.yaml post /api/assets/from-hash openapi: 3.0.3 info: title: Comfy Cloud API description: > **Experimental API:** This API is experimental and subject to change. Endpoints, request/response formats, and behavior may be modified without notice. API for Comfy Cloud - Run ComfyUI workflows on cloud infrastructure. This API allows you to interact with Comfy Cloud programmatically, including: - Submitting and managing workflows - Uploading and downloading files - Monitoring job status and progress ## Cloud vs OSS ComfyUI Compatibility Comfy Cloud implements the same API interfaces as OSS ComfyUI for maximum compatibility, but some fields are accepted for compatibility while being handled differently or ignored: | Field | Endpoints | Cloud Behavior | |-------|-----------|----------------| | `subfolder` | `/api/view`, `/api/upload/*` | **Ignored** - Cloud uses content-addressed storage (hash-based). Returned in responses for client-side organization. | | `type` (input/output/temp) | `/api/view`, `/api/upload/*` | Partially used - All files stored with tag-based organization rather than directory structure. | | `overwrite` | `/api/upload/*` | **Ignored** - Content-addressed storage means identical content always has the same hash. | | `number`, `front` | `/api/prompt` | **Ignored** - Cloud uses its own fair queue scheduling per user. | | `split`, `full_info` | `/api/userdata` | **Ignored** - Cloud always returns full file metadata. | These fields are retained in the API schema for drop-in compatibility with existing ComfyUI clients and workflows. version: 1.0.0 license: name: GNU General Public License v3.0 url: https://github.com/comfyanonymous/ComfyUI/blob/master/LICENSE servers: - url: https://cloud.comfy.org description: Comfy Cloud API security: - ApiKeyAuth: [] tags: - name: workflow description: | Submit workflows for execution and manage the execution queue. This is the primary way to run ComfyUI workflows on the cloud. - name: job description: | Monitor job status, view execution history, and manage running jobs. Jobs are created when you submit a workflow via POST /api/prompt. - name: asset description: | Upload, download, and manage persistent assets (images, models, outputs). Assets provide durable storage with tagging and metadata support. - name: file description: | Legacy file upload and download endpoints compatible with local ComfyUI. For new integrations, consider using the Assets API instead. - name: model description: | Browse available AI models. Models are pre-loaded on cloud infrastructure. - name: node description: | Get information about available ComfyUI nodes and their inputs/outputs. Useful for building dynamic workflow interfaces. - name: user description: | User account information and personal data storage. - name: system description: | Server status, health checks, and system information. paths: /api/assets/from-hash: post: tags: - asset summary: Create asset reference from existing hash description: > Creates a new asset reference using an existing hash from cloud storage. This avoids re-uploading file content when the underlying data already exists, which is useful for large files or when referencing well-known assets. The user provides their own metadata and tags for the new reference. operationId: createAssetFromHash requestBody: required: true content: application/json: schema: type: object required: - hash - tags properties: hash: type: string description: >- Hash of the existing asset. Supports Blake3 (blake3:) or SHA256 (sha256:) formats pattern: ^(blake3|sha256):[a-f0-9]{64}$ name: type: string description: Display name for the asset reference (optional) tags: type: array items: type: string minItems: 1 description: >- Freeform tags for the asset. Common types include "models", "input", "output", and "temp", but any tag can be used in any order. mime_type: type: string description: MIME type of the asset (e.g., "image/png", "video/mp4") user_metadata: type: object description: Custom metadata for this asset reference additionalProperties: true responses: '200': description: Asset reference already exists (returned existing) content: application/json: schema: $ref: '#/components/schemas/AssetCreated' '201': description: Asset reference created successfully content: application/json: schema: $ref: '#/components/schemas/AssetCreated' '400': description: Invalid request (bad hash format, invalid tags, etc.) content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '404': description: Source asset with given hash not found content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': description: Internal server error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' components: schemas: AssetCreated: allOf: - $ref: '#/components/schemas/Asset' - type: object required: - created_new properties: created_new: type: boolean description: >- Whether this was a new asset creation (true) or returned existing (false) ErrorResponse: type: object required: - code - message properties: code: type: string message: type: string Asset: type: object required: - id - name - size - created_at - updated_at properties: id: type: string format: uuid description: Unique identifier for the asset name: type: string description: Name of the asset file asset_hash: type: string description: Blake3 hash of the asset content pattern: ^blake3:[a-f0-9]{64}$ size: type: integer format: int64 description: Size of the asset in bytes mime_type: type: string description: MIME type of the asset tags: type: array items: type: string description: Tags associated with the asset user_metadata: type: object description: Custom user metadata for the asset additionalProperties: true preview_url: type: string format: uri description: URL for asset preview/thumbnail preview_id: type: string format: uuid description: ID of the preview asset if available nullable: true prompt_id: type: string format: uuid description: ID of the job/prompt that created this asset, if available nullable: true created_at: type: string format: date-time description: Timestamp when the asset was created updated_at: type: string format: date-time description: Timestamp when the asset was last updated last_access_time: type: string format: date-time description: Timestamp when the asset was last accessed is_immutable: type: boolean description: Whether this asset is immutable (cannot be modified or deleted) securitySchemes: ApiKeyAuth: type: apiKey in: header name: X-API-Key description: > API key authentication. Generate an API key from your account settings at https://platform.comfy.org/profile/api-keys. Pass the key in the X-API-Key header. ````