End of support notice: On October 7th, 2026, AWS will discontinue support for AWS IoT Greengrass Version 1. After October 7th, 2026, you will no longer be able to access the AWS IoT Greengrass V1 resources. For more information, please visit [Migrate from AWS IoT Greengrass Version 1](https://docs.aws.amazon.com/greengrass/v2/developerguide/migrate-from-v1.html).

# /greengrass/definition/cores


## GET


 `GET /greengrass/definition/cores`

Operation ID: [ListCoreDefinitions](listcoredefinitions-get.md)

Retrieves a list of core definitions.

Produces: application/json

### Query Parameters


[**MaxResults**](parameters-maxresultsparam.md)  
The maximum number of results to be returned per request.  
where used: query; required: false  
type: integer

[**NextToken**](parameters-nexttokenparam.md)  
The token for the next set of results, or `null` if there are no more results.  
where used: query; required: false  
type: string

### CLI


```
aws greengrass list-core-definitions \
  [--max-results <value>] \
  [--next-token <value>]  \
  [--cli-input-json <value>] \
  [--generate-cli-skeleton]
```

cli-input-json format:

```
{
"MaxResults": "integer",
"NextToken": "string"
}
```

### Responses


**200** (ListCoreDefinitionsResponse)  
  
 [ ListDefinitionsResponse](definitions-listdefinitionsresponse.md)   

```
{
"Definitions": [
  {
    "Name": "string",
    "Id": "string",
    "Arn": "string",
    "tags": {
      "additionalProperty0": "string",
      "additionalProperty1": "string",
      "additionalProperty2": "string"
    },
    "LastUpdatedTimestamp": "string",
    "CreationTimestamp": "string",
    "LatestVersion": "string",
    "LatestVersionArn": "string"
  }
],
"NextToken": "string"
}
```  
ListDefinitionsResponse  
A list of definitions.  
type: object  
Definitions  
Information about a definition.  
type: array  
items: [DefinitionInformation](definitions-definitioninformation.md)  
DefinitionInformation  
Information about a definition.  
type: object  
Name  
The name of the definition.  
type: string  
Id  
The ID of the definition.  
type: string  
Arn  
The ARN of the definition.  
type: string  
tags  
The resource tags.  
type: object  
additionalProperties: The key-value pair for the resource tag. Type: string  
LastUpdatedTimestamp  
The time, in milliseconds since the epoch, when the definition was last updated.  
type: string  
CreationTimestamp  
The time, in milliseconds since the epoch, when the definition was created.  
type: string  
LatestVersion  
The ID of the latest version associated with the definition.  
type: string  
LatestVersionArn  
The ARN of the latest version associated with the definition.  
type: string  
NextToken  
The token for the next set of results, or `null` if there are no more results.  
type: string

## POST


 `POST /greengrass/definition/cores`

Operation ID: [CreateCoreDefinition](createcoredefinition-post.md)

Creates a core definition. You can provide the initial version of the core definition now or use `CreateCoreDefinitionVersion` later. Greengrass groups must each contain exactly one Greengrass core.

Produces: application/json

### Body Parameters


[**CreateCoreDefinitionRequestBody**](parameters-createcoredefinitionrequestbody.md)  
Information required to create a core definition.  
where used: body; required: true  

```
{
"Name": "string",
"InitialVersion": {
  "Cores": [
    {
      "Id": "string",
      "ThingArn": "string",
      "CertificateArn": "string",
      "SyncShadow": true
    }
  ]
},
"tags": {
  "additionalProperty0": "string",
  "additionalProperty1": "string",
  "additionalProperty2": "string"
}
}
```  
Name  
The name of the core definition.  
type: string  
InitialVersion  
Information about a core definition version.  
type: object  
Cores  
A list of cores in the core definition version.  
type: array  
items: [Core](definitions-core.md)  
Core  
Information about a core.  
type: object  
required: ["Id", "ThingArn", "CertificateArn"]  
Id  
A descriptive or arbitrary ID for the core. This value must be unique within the core definition version. Maximum length is 128 characters with the pattern `[a‑zA‑Z0‑9:_‑]+`.  
type: string  
ThingArn  
The ARN of the thing that is the core.  
type: string  
CertificateArn  
The ARN of the certificate associated with the core.  
type: string  
SyncShadow  
If true, the core's local shadow is synced with the cloud automatically.  
type: boolean  
tags  
The resource tags.  
type: object  
additionalProperties: The key-value pair for the resource tag. Type: string

### Header Parameters


[**X-Amzn-Client-Token**](parameters-clienttoken.md)  
A client token used to correlate requests and responses.  
where used: header; required: false  
type: string

### CLI


```
aws greengrass create-core-definition \
  [--name <value>] \
  [--initial-version <value>] \
  [--tags <value>] \
  [--amzn-client-token <value>]  \
  [--cli-input-json <value>] \
  [--generate-cli-skeleton]
```

cli-input-json format:

```
{
"Name": "string",
"InitialVersion": {
  "Cores": [
    {
      "Id": "string",
      "ThingArn": "string",
      "CertificateArn": "string",
      "SyncShadow": "boolean"
    }
  ]
},
"tags": {
  "additionalProperty0": "string",
  "additionalProperty1": "string",
  "additionalProperty2": "string"
},
"AmznClientToken": "string"
}
```

### Responses


**200** (CreateCoreDefinitionResponse)  
  
 [ DefinitionInformation](definitions-definitioninformation.md)   

```
{
"Name": "string",
"Id": "string",
"Arn": "string",
"LastUpdatedTimestamp": "string",
"CreationTimestamp": "string",
"LatestVersion": "string",
"LatestVersionArn": "string"
}
```  
DefinitionInformation  
Information about a definition.  
type: object  
Name  
The name of the definition.  
type: string  
Id  
The ID of the definition.  
type: string  
Arn  
The ARN of the definition.  
type: string  
LastUpdatedTimestamp  
The time, in milliseconds since the epoch, when the definition was last updated.  
type: string  
CreationTimestamp  
The time, in milliseconds since the epoch, when the definition was created.  
type: string  
LatestVersion  
The ID of the latest version associated with the definition.  
type: string  
LatestVersionArn  
The ARN of the latest version associated with the definition.  
type: string

**400**  
Invalid request.  
 [ GeneralError](definitions-generalerror.md)   

```
{
"Message": "string",
"ErrorDetails": [
  {
    "DetailedErrorCode": "string",
    "DetailedErrorMessage": "string"
  }
]
}
```  
GeneralError  
General error information.  
type: object  
required: ["Message"]  
Message  
A message that contains information about the error.  
type: string  
ErrorDetails  
A list of error details.  
type: array  
items: [ErrorDetail](definitions-errordetail.md)  
ErrorDetail  
Details about the error.  
type: object  
DetailedErrorCode  
A detailed error code.  
type: string  
DetailedErrorMessage  
A detailed error message.  
type: string