--- title: Create Variable Definition slug: feature-experimentation/api/create-variable-definition docTags: createdAt: 2026-08-28T15:54:06.731Z --- { "id": "wrs3o_qcRtdCWl5_x_O_K", "type": "api-oas-v2", "data": { "method": "POST", "url": "https://api.optimizely.com/flags/v1//projects/{project_id}/flags/{flag_key}/variable_definitions", "servers": [ { "url": "https://api.optimizely.com/flags/v1//projects/{project_id}/flags/{flag_key}/variable_definitions" } ], "name": "Create Variable Definition", "description": "Create Variable Definition\n", "contentType": "application/json", "request": { "pathParameters": [ { "kind": "required", "name": "flag_key", "type": "string", "example": "recurring_deposit", "description": "The Flag identifier" }, { "kind": "required", "name": "project_id", "type": "integer", "example": 12345, "description": "The project identifier" } ], "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", "example": "{\"default_value\":\"my_default_str\",\"description\":\"some description\",\"key\":\"variable_definition_key\",\"type\":\"string\"}", "description": "", "customType": "VariableDefinition", "schema": [ { "name": "default_value", "kind": "required", "type": "string", "description": "The default value for the Flag Variable Definition", "example": "0.0" }, { "name": "description", "kind": "optional", "type": "string", "description": "Additional context of the Flag Variable Definition", "example": "This variable is used to configure the amount used for computing the discount" }, { "name": "key", "kind": "required", "type": "string", "description": "Unique string identifier for the Flag Variable Definition within the Flag", "example": "amount" }, { "name": "type", "kind": "required", "type": "string", "description": "The datatype for the Flag Variable Definition", "example": "double", "enum": [ "boolean", "string", "double", "integer", "json" ] } ], "modelRef": "#/components/schemas/VariableDefinition", "isExpanded": true } ], "formDataParameters": [], "oAuthParameters": [ { "id": "apiKey", "name": "apiKey", "kind": "optional", "type": "http", "scheme": "bearer" }, { "id": "OAuth2", "name": "OAuth2", "kind": "optional", "type": "oauth2", "description": "Write applications that authenticate with the REST API via OAuth 2.0.", "oauth2Flows": { "authorizationCode": { "authorizationUrl": "https://app.optimizely.com/oauth2/authorize", "tokenUrl": "https://app.optimizely.com/oauth2/token", "scopes": { "all": "Grants all access" } } }, "requiredScopes": [ "read", "write" ] } ], "cookieParameters": [] }, "responses": [ { "statusCode": "200", "description": "Create a variable definition\n", "jsonExample": "", "isExpanded": true, "schema": [ { "kind": "optional", "type": "object", "example": "{\"default_value\":\"my_default_str\",\"description\":\"some description\",\"key\":\"variable_definition_key\",\"type\":\"string\"}", "description": "", "customType": "VariableDefinition", "schema": [ { "name": "default_value", "kind": "required", "type": "string", "description": "The default value for the Flag Variable Definition", "example": "0.0" }, { "name": "description", "kind": "optional", "type": "string", "description": "Additional context of the Flag Variable Definition", "example": "This variable is used to configure the amount used for computing the discount" }, { "name": "key", "kind": "required", "type": "string", "description": "Unique string identifier for the Flag Variable Definition within the Flag", "example": "amount" }, { "name": "revision", "kind": "optional", "type": "integer", "readOnly": true, "description": "Revision number for tracking changes" }, { "name": "role", "kind": "optional", "type": "string", "readOnly": true, "description": "Granular permission role", "example": "admin" }, { "name": "type", "kind": "required", "type": "string", "description": "The datatype for the Flag Variable Definition", "example": "double", "enum": [ "boolean", "string", "double", "integer", "json" ] } ], "modelRef": "#/components/schemas/VariableDefinition", "isExpanded": true } ] }, { "statusCode": "400", "description": "Malformed requests and invalid parameter names and types", "jsonExample": "", "isExpanded": true }, { "statusCode": "401", "description": "Invalid credentials", "jsonExample": "", "isExpanded": true }, { "statusCode": "403", "description": "Do not have permission to perform the operation", "jsonExample": "", "isExpanded": true }, { "statusCode": "404", "description": "Not found. No content", "jsonExample": "", "isExpanded": true }, { "statusCode": "409", "description": "Conflicting resource state with requested action", "jsonExample": "", "isExpanded": true } ], "hasXCodeSamples": false, "examples": { "languages": [ { "id": "Pdxf-Y61yQ75g26pJQTCk", "language": "curl", "label": "cURL", "code": "curl --request POST \\\n --url https://api.optimizely.com/flags/v1//projects/{project_id}/flags/{flag_key}/variable_definitions \\\n --header 'accept: application/json' \\\n --header 'content-type: application/json' \\\n --data '{\n \"default_value\": \"0.0\",\n \"key\": \"amount\",\n \"type\": \"double\"\n }'" }, { "id": "nQCh7VSSbury2hYnMqlmn", "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 \"default_value\": \"0.0\",\n \"key\": \"amount\",\n \"type\": \"double\"\n});\n\nvar requestOptions = {\n method: 'POST',\n headers: myHeaders,\n body: raw,\n redirect: 'follow'\n};\n\nfetch(\"https://api.optimizely.com/flags/v1//projects/{project_id}/flags/{flag_key}/variable_definitions\", requestOptions)\n .then(response => response.text())\n .then(result => console.log(result))\n .catch(error => console.log('error', error));" }, { "id": "jXWukgz4UrPu0kKnx4zv2", "language": "ruby", "label": "Ruby", "code": "require \"uri\"\nrequire \"json\"\nrequire \"net/http\"\n\nurl = URI(\"https://api.optimizely.com/flags/v1//projects/{project_id}/flags/{flag_key}/variable_definitions\")\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 \"default_value\": \"0.0\",\n \"key\": \"amount\",\n \"type\": \"double\"\n})\n\nresponse = https.request(request)\nputs response.read_body\n" }, { "id": "djq97vLTXyxUhupeW1okQ", "language": "python", "label": "Python", "code": "import requests\nimport json\n\nurl = \"https://api.optimizely.com/flags/v1//projects/{project_id}/flags/{flag_key}/variable_definitions\"\n\npayload = json.dumps({\n \"default_value\": \"0.0\",\n \"key\": \"amount\",\n \"type\": \"double\"\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": "Pdxf-Y61yQ75g26pJQTCk" }, "results": { "languages": [ { "id": "response-0-200", "language": "200", "code": "// Create a variable definition\n{\n \"default_value\": \"0.0\",\n \"description\": \"This variable is used to configure the amount used for computing the discount\",\n \"key\": \"amount\",\n \"revision\": 0,\n \"role\": \"admin\",\n \"type\": \"double\"\n}" }, { "id": "response-1-400", "language": "400", "code": "// Malformed requests and invalid parameter names and types\n" }, { "id": "response-2-401", "language": "401", "code": "// Invalid credentials\n" }, { "id": "response-3-403", "language": "403", "code": "// Do not have permission to perform the operation\n" }, { "id": "response-4-404", "language": "404", "code": "// Not found. No content\n" }, { "id": "response-5-409", "language": "409", "code": "// Conflicting resource state with requested action\n" } ], "selectedLanguageId": "response-0-200" } }, "children": [ { "text": "" } ] }