---
updatedAt: 2026-04-21T04:46:34.000Z
agentTools:
  projectIndex: https://developer.alloy.com/public/llms.txt
---

# Create a New Custom List

Create a new custom list with input metadata

# OpenAPI definition

```json
{
  "openapi": "3.0.0",
  "info": {
    "title": "Alloy API",
    "version": "1.0.0",
    "description": "hey hey hey, it's the Alloy API!"
  },
  "servers": [
    {
      "url": "https://sandbox.alloy.co/v1",
      "description": "Sandbox endpoint"
    }
  ],
  "security": [
    {
      "oauth2": []
    },
    {
      "basic": []
    }
  ],
  "tags": [
    {
      "name": "Custom Lists",
      "description": "Match inbound values against any data element sent in to Alloy. These lists can be used for standard Allow or Denylist purposes, or for more custom matching use cases."
    }
  ],
  "paths": {
    "/custom-lists": {
      "post": {
        "tags": [
          "Custom Lists"
        ],
        "summary": "Create a New Custom List",
        "description": "Create a new custom list with input metadata",
        "requestBody": {
          "required": true,
          "content": {
            "application/json": {
              "schema": {
                "type": "object",
                "required": [
                  "name"
                ],
                "properties": {
                  "name": {
                    "type": "string",
                    "description": "Name of the custom list"
                  },
                  "description": {
                    "type": "string",
                    "description": "Description of the custom list"
                  }
                }
              }
            }
          }
        },
        "responses": {
          "201": {
            "description": "Successfully created a custom list",
            "content": {
              "application/json": {
                "schema": {
                  "type": "object",
                  "properties": {
                    "custom_list_token": {
                      "type": "string"
                    },
                    "created_at": {
                      "type": "string",
                      "format": "date-time"
                    }
                  }
                }
              }
            }
          },
          "400": {
            "description": "Bad request - Missing Required Fields"
          },
          "403": {
            "description": "Forbidden - Insufficient Permissions"
          },
          "409": {
            "description": "Conflict - List Name Already Exists"
          }
        }
      }
    }
  },
  "components": {
    "securitySchemes": {
      "basic": {
        "type": "http",
        "description": "HTTP basic authorization using a workflow token and secret",
        "scheme": "basic"
      },
      "oauth2": {
        "type": "oauth2",
        "description": "Oauth2 using a workflow token and secret to generate a bearer token",
        "flows": {
          "clientCredentials": {
            "tokenUrl": "/oauth/bearer",
            "scopes": {}
          }
        }
      }
    }
  },
  "x-readme": {
    "explorer-enabled": false
  }
}
```