---
updatedAt: 2026-06-08T03:35:06.000Z
agentTools:
  projectIndex: https://developer.moloco.cloud/llms.txt
---

# Create a new asset upload session.

Create a new asset upload session for the AdAccount. A URL would be returned in a successful response for uploading the actual asset content.
After asset upload has been successfully completed, see [the campaign creation guide](https://developer.moloco.cloud/docs/campaign-management-api) and follow [Section 4-1 for those using Moloco Ads API v1.7 or later](https://developer.moloco.cloud/docs/campaign-management-api#4-1-upload-a-creative-asset-to-storage-for-those-using-moloco-ads-api-v17-or-later)

# OpenAPI definition

```json
{
  "openapi": "3.0.0",
  "info": {
    "title": "Moloco Ads Campaign Management API",
    "description": "Moloco Ads Campaign Management API provides functionalities for Moloco Ads Campaigns.",
    "version": "1.10",
    "contact": {
      "name": "Moloco Inc.",
      "url": "https://www.moloco.com"
    }
  },
  "paths": {
    "/cm/v1/creative-assets": {
      "post": {
        "summary": "Create a new asset upload session.",
        "description": "Create a new asset upload session for the AdAccount. A URL would be returned in a successful response for uploading the actual asset content.\nAfter asset upload has been successfully completed, see [the campaign creation guide](https://developer.moloco.cloud/docs/campaign-management-api) and follow [Section 4-1 for those using Moloco Ads API v1.7 or later](https://developer.moloco.cloud/docs/campaign-management-api#4-1-upload-a-creative-asset-to-storage-for-those-using-moloco-ads-api-v17-or-later)",
        "operationId": "DspApi_CreateAssetUploadSession",
        "responses": {
          "200": {
            "description": "A successful response.",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/messagesCreateAssetUploadSessionResponse"
                }
              }
            }
          },
          "default": {
            "description": "Error. Detailed cause can be found in the `details` field.",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/messagesCreateAssetUploadSessionError"
                }
              }
            }
          }
        },
        "parameters": [
          {
            "name": "ad_account_id",
            "description": "The AdAccount ID.",
            "in": "query",
            "required": true,
            "schema": {
              "type": "string"
            }
          }
        ],
        "requestBody": {
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/CreateAssetUploadSessionRequestAssetUploadSessionInfo"
              }
            }
          },
          "description": "The information to upload the asset.",
          "required": true
        },
        "tags": [
          "Creative"
        ]
      }
    }
  },
  "security": [
    {
      "Bearer": []
    }
  ],
  "servers": [
    {
      "url": "https://api.moloco.cloud"
    }
  ],
  "components": {
    "securitySchemes": {
      "Bearer": {
        "type": "apiKey",
        "name": "Authorization",
        "in": "header"
      }
    },
    "schemas": {
      "CreateAssetUploadSessionRequestAssetUploadSessionInfo": {
        "type": "object",
        "properties": {
          "asset_kind": {
            "$ref": "#/components/schemas/commonAssetKind",
            "description": "The kind of asset."
          },
          "mime_type": {
            "type": "string",
            "description": "MIME type of the asset to upload."
          }
        },
        "required": [
          "asset_kind",
          "mime_type"
        ]
      },
      "commonAssetKind": {
        "type": "string",
        "enum": [
          "UNKNOWN_ASSET_KIND",
          "CREATIVE",
          "CSV",
          "ASSET_DYNAMIC_CREATIVE",
          "FB_PLAYABLE_AD"
        ],
        "default": "UNKNOWN_ASSET_KIND",
        "description": "List of asset kinds supported by Moloco Ads.\n\n - UNKNOWN_ASSET_KIND: This value is not part of the specification.\n - CREATIVE: Creative asset type.\n - CSV: text/csv type.\n - ASSET_DYNAMIC_CREATIVE: Asset for Dynamic Creatives.\n - FB_PLAYABLE_AD: Facebook Playable AD."
      },
      "messagesCreateAssetUploadSessionError": {
        "type": "object",
        "properties": {
          "code": {
            "type": "integer",
            "format": "int32"
          },
          "message": {
            "type": "string"
          },
          "details": {
            "type": "array",
            "items": {
              "type": "object",
              "$ref": "#/components/schemas/messagesCreateAssetUploadSessionErrorAPIErrorInfo"
            }
          }
        },
        "title": "creative related errors"
      },
      "messagesCreateAssetUploadSessionErrorAPIErrorInfo": {
        "type": "object",
        "properties": {
          "reason": {
            "$ref": "#/components/schemas/messagesCreateAssetUploadSessionErrorAPIErrorInfoErrorReason"
          },
          "error_log_id": {
            "type": "string"
          },
          "context": {
            "type": "object",
            "additionalProperties": {
              "type": "string"
            }
          }
        }
      },
      "messagesCreateAssetUploadSessionErrorAPIErrorInfoErrorReason": {
        "type": "string",
        "enum": [
          "ERROR_REASON_UNKNOWN"
        ],
        "default": "ERROR_REASON_UNKNOWN"
      },
      "messagesCreateAssetUploadSessionResponse": {
        "type": "object",
        "properties": {
          "asset_url": {
            "type": "string",
            "description": "Actual URL to reach to the asset."
          },
          "content_upload_url": {
            "type": "string",
            "description": "Temporal URL to upload the actual content of the asset. It will be expired in an hour.\n\nTo update the asset content, follow [the instruction](https://developer.moloco.cloud/docs/campaign-management-api#4-1-upload-a-creative-asset-to-storage-for-those-using-moloco-ads-api-v17-or-later)."
          }
        },
        "description": "Response that contains information for the created asset upload session."
      }
    }
  }
}
```