model.json Structure

The model.json file defines all your dynamic entities, their properties, enums, relationships, interceptors, custom endpoints, and UI configurations. It is an alternative configuration source to C# Attributes and Fluent API, ideal when you prefer a declarative JSON approach.

File Location

Place your model.json in a _Dynamic folder inside your Domain project:

YourApp.Domain/
└── _Dynamic/
    └── model.json

The module automatically discovers and loads this file at application startup.

A JSON Schema file (model.schema.json) is available in the module source for IDE IntelliSense. Reference it using the $schema property:

{
  "$schema": "path/to/model.schema.json",
  "entities": []
}

Top-Level Structure

The model.json file has three root sections:

{
  "$schema": "...",
  "enums": [],
  "entities": [],
  "endpoints": []
}

Enum Definitions

Define enums that can be used as property types:

{
  "enums": [
    {
      "name": "LowCodeDemo.Organizations.OrganizationType",
      "values": [
        { "name": "Corporate", "value": 0 },
        { "name": "Enterprise", "value": 1 },
        { "name": "Startup", "value": 2 },
        { "name": "Consulting", "value": 3 }
      ]
    }
  ]
}

Reference enums in entity properties using the enumType field:

{
  "name": "OrganizationType",
  "enumType": "LowCodeDemo.Organizations.OrganizationType"
}

Entity Definition

Each entity has the following structure:

{
  "name": "LowCodeDemo.Products.Product",
  "displayProperty": "Name",
  "parent": null,
  "properties": [],
  "interceptors": [],
  "ui": {}
}

Entity Attributes

Parent-Child Relationships

Use the parent field to create nested entities. Children are managed through the parent entity's UI:

{
  "name": "LowCodeDemo.Orders.OrderLine",
  "parent": "LowCodeDemo.Orders.Order",
  "properties": [
    {
      "name": "ProductId",
      "foreignKey": {
        "entityName": "LowCodeDemo.Products.Product"
      }
    },
    { "name": "Quantity", "type": "int" },
    { "name": "Amount", "type": "decimal" }
  ]
}

Multi-level nesting is supported (e.g., Order > OrderLine > ShipmentItem > ShipmentTracking).

Property Definition

{
  "name": "Price",
  "type": "decimal",
  "isRequired": true,
  "isUnique": false,
  "isMappedToDbField": true,
  "serverOnly": false,
  "allowSetByClients": true,
  "enumType": null,
  "foreignKey": null,
  "validators": [],
  "ui": {}
}

Property Types

Property Flags

Foreign Key Properties

Define a foreign key relationship inline on a property:

{
  "name": "CustomerId",
  "foreignKey": {
    "entityName": "LowCodeDemo.Customers.Customer",
    "displayPropertyName": "Name",
    "access": "edit"
  }
}

Note: Reference entities are existing C# entities (like ABP's IdentityUser) that are registered for read-only access. Unlike dynamic entities, they don't get CRUD pages — they're used only for foreign key lookups and display values.

Validators

Add validation rules to properties:

{
  "name": "EmailAddress",
  "validators": [
    { "type": "required" },
    { "type": "emailAddress" },
    { "type": "minLength", "length": 5 },
    { "type": "maxLength", "length": 255 }
  ]
}

Additional validator examples:

{
  "name": "Website",
  "validators": [
    { "type": "url", "message": "Please enter a valid URL" }
  ]
},
{
  "name": "PhoneNumber",
  "validators": [
    { "type": "phone" }
  ]
},
{
  "name": "ProductCode",
  "validators": [
    { "type": "regularExpression", "pattern": "^[A-Z]{3}-\\d{4}$", "message": "Code must be in format ABC-1234" }
  ]
},
{
  "name": "Price",
  "type": "decimal",
  "validators": [
    { "type": "range", "minimum": 0.01, "maximum": 99999.99 }
  ]
}

All validators accept an optional message parameter for a custom error message. The regularExpression validator also accepts the alias pattern, and emailAddress also accepts email.

UI Configuration

Entity-Level UI

{
  "ui": {
    "pageTitle": "Products"
  }
}

Only entities with ui.pageTitle get a menu item and a dedicated page in the UI.

Property-Level UI

{
  "name": "RegistrationNumber",
  "ui": {
    "displayName": "Registration Number",
    "isAvailableOnDataTable": true,
    "isAvailableOnDataTableFiltering": true,
    "creationFormAvailability": "Hidden",
    "editingFormAvailability": "NotAvailable",
    "quickLookOrder": 100
  }
}

Form Availability Values

Interceptors

Define JavaScript interceptors for CRUD lifecycle hooks:

{
  "interceptors": [
    {
      "commandName": "Create",
      "type": "Pre",
      "javascript": "if(!context.commandArgs.data['Name']) { globalError = 'Name is required!'; }"
    }
  ]
}

See Interceptors for details.

Endpoints

Define custom REST endpoints with JavaScript handlers:

{
  "endpoints": [
    {
      "name": "GetProductStats",
      "route": "/api/custom/products/stats",
      "method": "GET",
      "requireAuthentication": false,
      "javascript": "var count = await db.count('Products.Product'); return ok({ total: count });"
    }
  ]
}

See Custom Endpoints for details.

Complete Example

{
  "enums": [
    {
      "name": "ShipmentStatus",
      "values": [
        { "name": "Pending", "value": 0 },
        { "name": "Shipped", "value": 2 },
        { "name": "Delivered", "value": 4 }
      ]
    }
  ],
  "entities": [
    {
      "name": "LowCodeDemo.Products.Product",
      "displayProperty": "Name",
      "properties": [
        { "name": "Name", "isUnique": true, "isRequired": true },
        { "name": "Price", "type": "decimal" },
        { "name": "StockCount", "type": "int" },
        { "name": "ReleaseDate", "type": "DateTime" }
      ],
      "ui": { "pageTitle": "Products" }
    },
    {
      "name": "LowCodeDemo.Orders.Order",
      "displayProperty": "Id",
      "properties": [
        {
          "name": "CustomerId",
          "foreignKey": {
            "entityName": "LowCodeDemo.Customers.Customer",
            "access": "edit"
          }
        },
        { "name": "TotalAmount", "type": "decimal" },
        { "name": "IsDelivered", "type": "boolean" }
      ],
      "interceptors": [
        {
          "commandName": "Create",
          "type": "Post",
          "javascript": "context.log('Order created: ' + context.commandArgs.entityId);"
        }
      ],
      "ui": { "pageTitle": "Orders" }
    },
    {
      "name": "LowCodeDemo.Orders.OrderLine",
      "parent": "LowCodeDemo.Orders.Order",
      "properties": [
        {
          "name": "ProductId",
          "foreignKey": { "entityName": "LowCodeDemo.Products.Product" }
        },
        { "name": "Quantity", "type": "int" },
        { "name": "Amount", "type": "decimal" }
      ]
    }
  ]
}

Migration Requirements

When you modify model.json, you need database migrations for the changes to take effect:

• New entity: dotnet ef migrations add Added_{EntityName}
• New property: dotnet ef migrations add Added_{PropertyName}_To_{EntityName}
• Type change: dotnet ef migrations add Changed_{PropertyName}_In_{EntityName}

The same migration requirement applies when using C# Attributes. Any change to entity structure requires an EF Core migration.

See Also

• Attributes & Fluent API
• Interceptors
• Custom Endpoints
• Scripting API