---
title: POST /v3/multipart-uploads
slug: content-marketing-platform/api/post-v3multipart-uploads
docTags:
createdAt: 2026-10-01T18:51:26.265Z
---
{
"id": "Z3MPNt_MafO8HJhojW5RT",
"type": "api-oas-v2",
"data": {
"method": "POST",
"url": "https://api.cmp.optimizely.com/v3/multipart-uploads",
"servers": [
{
"url": "https://api.cmp.optimizely.com/v3/multipart-uploads",
"description": "v3 version of Optimizely CMP Open API"
}
],
"name": "POST /v3/multipart-uploads",
"description": "Experimental Create pre-signed URLs for multipart upload of large files
",
"contentType": "application/json",
"request": {
"pathParameters": [],
"headerParameters": [
{
"name": "accept",
"type": "string",
"kind": "optional",
"description": "Generated from available response content types",
"enum": [
"application/json"
],
"default": "application/json"
}
],
"queryParameters": [],
"bodyDataParameters": [
{
"kind": "required",
"name": "body",
"type": "object",
"description": "",
"schema": [
{
"name": "file_size",
"kind": "required",
"type": "integer",
"description": "Size of the file in bytes",
"example": 104857600,
"minimum": 1,
"maximum": 5497558138880
},
{
"name": "part_size",
"kind": "optional",
"type": "integer",
"description": "The size of each part of the file to be uploaded. The size of the last part can be smaller and hence can be ignored. upload_part_count is calculated based on file_size and part_size. The maximum allowed upload_part_count is 10000. So use larger part_size for larger files to keep upload_part_count under 10000.
",
"example": 6000000,
"default": 5242880,
"minimum": 5242880,
"maximum": 5368709120
}
],
"isExpanded": true
}
],
"formDataParameters": [],
"oAuthParameters": [
{
"id": "OAuth2",
"name": "OAuth2",
"kind": "optional",
"type": "oauth2",
"oauth2Flows": {
"clientCredentials": {
"tokenUrl": "https://accounts.cmp.optimizely.com/o/oauth2/v1/token",
"scopes": {}
},
"authorizationCode": {
"authorizationUrl": "https://accounts.cmp.optimizely.com/o/oauth2/v1/auth",
"tokenUrl": "https://accounts.cmp.optimizely.com/o/oauth2/v1/token",
"scopes": {
"openid": "Grants the ability to receive a unique identifier for the user.",
"profile": "Grants access to user profile information.",
"offline_access": "Grants the ability to refresh access_token using the refresh token even when user is not present (not logged in)."
}
}
},
"requiredScopes": [
"openid",
"profile",
"offline_access"
]
}
],
"cookieParameters": []
},
"responses": [
{
"statusCode": "201",
"description": "Successful operation",
"jsonExample": "",
"isExpanded": true,
"headers": [
{
"kind": "optional",
"name": "Content-Encoding",
"type": "string",
"example": "gzip",
"description": "Response is always gzip compressed",
"enum": [
"gzip"
]
}
],
"schema": [
{
"kind": "optional",
"type": "object",
"description": "",
"schema": [
{
"name": "id",
"kind": "required",
"type": "string",
"description": "ID of the multipart upload",
"example": "abcdef1234567890"
},
{
"name": "expires_at",
"kind": "required",
"type": "string",
"description": "Expiration time of the upload URLs",
"example": "2025-03-03T12:00:00Z",
"format": "date-time"
},
{
"name": "upload_part_count",
"kind": "required",
"type": "integer",
"description": "Number of parts for the upload",
"example": 10
},
{
"name": "upload_part_urls",
"kind": "required",
"type": "array",
"description": "Array of pre-signed URLs for each part. Each file part must be uploaded to the URL using PUT requests following the order of the URLs
",
"example": "[\"https://s3.amazonaws.com/xyz/abcdef1234567890/0\",\"https://s3.amazonaws.com/xyz/abcdef1234567890/1\"]",
"itemType": "string",
"customType": "string[]",
"itemExample": "",
"itemDefault": ""
},
{
"name": "links",
"kind": "required",
"type": "object",
"description": "",
"example": "",
"schema": [
{
"name": "complete",
"kind": "required",
"type": "string",
"description": "URL to complete the upload",
"example": "https://api.cmp.optimizely.com/v3/multipart-uploads/abcdef1234567890/complete",
"format": "uri"
},
{
"name": "status",
"kind": "required",
"type": "string",
"description": "URL to check the upload status",
"example": "https://api.cmp.optimizely.com/v3/multipart-uploads/abcdef1234567890/status",
"format": "uri"
}
]
}
],
"isExpanded": true
}
]
},
{
"statusCode": "400",
"description": "Client error",
"jsonExample": "",
"isExpanded": true,
"schema": [
{
"kind": "optional",
"type": "object",
"example": "{\"message\":\"Unsupported arguments: a,b,c\"}",
"description": "Error payload",
"customType": "Error",
"schema": [
{
"name": "message",
"kind": "required",
"type": "string",
"description": "Message describing the error",
"example": "Not found"
},
{
"name": "errors",
"kind": "optional",
"type": "map",
"description": "Additional information",
"example": "",
"customType": "map",
"schema": []
}
],
"modelRef": "#/components/schemas/Error",
"isExpanded": true
}
]
},
{
"statusCode": "401",
"description": "Authorization error",
"jsonExample": "",
"isExpanded": true,
"schema": [
{
"kind": "optional",
"type": "object",
"example": "{\"message\":\"Unauthorized\"}",
"description": "Error payload",
"customType": "Error",
"schema": [
{
"name": "message",
"kind": "required",
"type": "string",
"description": "Message describing the error",
"example": "Not found"
},
{
"name": "errors",
"kind": "optional",
"type": "map",
"description": "Additional information",
"example": "",
"customType": "map",
"schema": []
}
],
"modelRef": "#/components/schemas/Error",
"isExpanded": true
}
]
},
{
"statusCode": "403",
"description": "Permission error",
"jsonExample": "",
"isExpanded": true,
"schema": [
{
"kind": "optional",
"type": "object",
"example": "{\"message\":\"You do not have the permission to perform this operation\"}",
"description": "Error payload",
"customType": "Error",
"schema": [
{
"name": "message",
"kind": "required",
"type": "string",
"description": "Message describing the error",
"example": "Not found"
},
{
"name": "errors",
"kind": "optional",
"type": "map",
"description": "Additional information",
"example": "",
"customType": "map",
"schema": []
}
],
"modelRef": "#/components/schemas/Error",
"isExpanded": true
}
]
},
{
"statusCode": "422",
"description": "Unprocessable entity error",
"jsonExample": "",
"isExpanded": true,
"schema": [
{
"kind": "optional",
"type": "object",
"example": "{\"message\":\"Resource cannot be processed\"}",
"description": "Error payload",
"customType": "Error",
"schema": [
{
"name": "message",
"kind": "required",
"type": "string",
"description": "Message describing the error",
"example": "Not found"
},
{
"name": "errors",
"kind": "optional",
"type": "map",
"description": "Additional information",
"example": "",
"customType": "map",
"schema": []
}
],
"modelRef": "#/components/schemas/Error",
"isExpanded": true
}
]
}
],
"hasXCodeSamples": false,
"examples": {
"languages": [
{
"id": "tTvi850RCnalTnXqmr06g",
"language": "curl",
"label": "cURL",
"code": "curl --request POST \\\n --url https://api.cmp.optimizely.com/v3/multipart-uploads \\\n --header 'accept: application/json' \\\n --header 'content-type: application/json' \\\n --data '{\n \"file_size\": 104857600,\n \"part_size\": 5242880\n }'"
},
{
"id": "GNFsddoBINavBHqWuOl4c",
"language": "javascript",
"label": "javascript",
"code": "var myHeaders = new Headers();\nmyHeaders.append(\"accept\", \"application/json\");\nmyHeaders.append(\"content-type\", \"application/json\");\n\nvar raw = JSON.stringify({\n \"file_size\": 104857600,\n \"part_size\": 5242880\n});\n\nvar requestOptions = {\n method: 'POST',\n headers: myHeaders,\n body: raw,\n redirect: 'follow'\n};\n\nfetch(\"https://api.cmp.optimizely.com/v3/multipart-uploads\", requestOptions)\n .then(response => response.text())\n .then(result => console.log(result))\n .catch(error => console.log('error', error));"
},
{
"id": "wC6R_ND5_Xs9TZrZPTnsM",
"language": "ruby",
"label": "Ruby",
"code": "require \"uri\"\nrequire \"json\"\nrequire \"net/http\"\n\nurl = URI(\"https://api.cmp.optimizely.com/v3/multipart-uploads\")\n\nhttps = Net::HTTP.new(url.host, url.port)\nhttps.use_ssl = true\n\nrequest = Net::HTTP::Post.new(url)\nrequest[\"accept\"] = \"application/json\"\nrequest[\"content-type\"] = \"application/json\"\nrequest.body = JSON.dump({\n \"file_size\": 104857600,\n \"part_size\": 5242880\n})\n\nresponse = https.request(request)\nputs response.read_body\n"
},
{
"id": "sEcQcEyl000qOdzzCO3gB",
"language": "python",
"label": "Python",
"code": "import requests\nimport json\n\nurl = \"https://api.cmp.optimizely.com/v3/multipart-uploads\"\n\npayload = json.dumps({\n \"file_size\": 104857600,\n \"part_size\": 5242880\n})\nheaders = {\n 'accept': 'application/json',\n 'content-type': 'application/json'\n}\n\nresponse = requests.request(\"POST\", url, headers=headers, data=payload)\n\nprint(response.text)\n"
}
],
"selectedLanguageId": "tTvi850RCnalTnXqmr06g"
},
"results": {
"languages": [
{
"id": "response-0-201",
"language": "201",
"code": "// Successful operation\n{\n \"id\": \"abcdef1234567890\",\n \"expires_at\": \"2025-03-03T12:00:00Z\",\n \"upload_part_count\": 10,\n \"upload_part_urls\": [\n \"\"\n ],\n \"links\": {\n \"complete\": \"https://api.cmp.optimizely.com/v3/multipart-uploads/abcdef1234567890/complete\",\n \"status\": \"https://api.cmp.optimizely.com/v3/multipart-uploads/abcdef1234567890/status\"\n }\n}"
},
{
"id": "response-1-400",
"language": "400",
"code": "// Client error\n{\n \"message\": \"Not found\",\n \"errors\": \"\"\n}"
},
{
"id": "response-2-401",
"language": "401",
"code": "// Authorization error\n{\n \"message\": \"Not found\",\n \"errors\": \"\"\n}"
},
{
"id": "response-3-403",
"language": "403",
"code": "// Permission error\n{\n \"message\": \"Not found\",\n \"errors\": \"\"\n}"
},
{
"id": "response-4-422",
"language": "422",
"code": "// Unprocessable entity error\n{\n \"message\": \"Not found\",\n \"errors\": \"\"\n}"
}
],
"selectedLanguageId": "response-0-201"
}
},
"children": [
{
"text": ""
}
]
}