> For the complete documentation index, see [llms.txt](https://help.mimeeq.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.mimeeq.com/api/custom-fields/list-custom-fields.md).

# List Custom Fields

List custom-field definitions for the requested `resourceType`, including system parameters.

Use `resourceType` to discover the definition keys and data types for one kind of record before reading or changing a field.

### Behaviour

Localized fields are translated to `lang` when supplied.

Requires the `customFields:read` scope.

```json
{"openapi":"3.1.0","info":{"title":"Mimeeq External API","version":"1.1.0"},"tags":[{"name":"Custom Fields","description":"Define additional fields for option-set options, cart submissions and product data-grid (bill of materials) items. A field definition describes the field’s key, label, data type, validation and display configuration; it is not the value entered on an individual record.\n\nUse this section to discover existing fields or configure the metadata an integration needs. For example, define an internal reference on an option or an additional field on a cart submission.\n\n## What you can do\n\n| Task | Reference |\n| --- | --- |\n| Find available custom fields | [List Custom Fields](https://help.mimeeq.com/developers/custom-fields/list-custom-fields) |\n| Add a new custom field | [Create Custom Field](https://help.mimeeq.com/developers/custom-fields/create-custom-field) |\n| Read one custom field | [Get Custom Field](https://help.mimeeq.com/developers/custom-fields/get-custom-field) |\n| Change custom field | [Update Custom Field](https://help.mimeeq.com/developers/custom-fields/update-custom-field) |\n| Remove custom field | [Delete Custom Field](https://help.mimeeq.com/developers/custom-fields/delete-custom-field) |\n\n## Before you start\n\nYour API key needs `customFields:read` to read these resources. Use `customFields:write` for write operations.\n\n## Important behaviour\n\nChoose `resourceType` on every request: `OPTION_SET`, CART or `PRODUCT_DATA_GRID`. The same field ID must be interpreted in its resource context. Lists include `SYSTEM` and `CUSTOM` definitions; system definitions cannot be changed. Updates replace the definition, so preserve every setting you want to keep. Deleting a definition is a schema change; do not assume it edits existing record values."}],"servers":[{"url":"https://admin.mimeeqapi.com","description":"Production API"}],"security":[{"apiKey":[]}],"components":{"securitySchemes":{"apiKey":{"type":"http","scheme":"bearer","description":"API key sent as a bearer token (mk_live_… / mk_test_…)."}},"schemas":{"CustomFieldsList":{"type":"object","properties":{"data":{"type":"array","items":{"type":"object","properties":{"parameterId":{"type":"string","pattern":"^PARAM-[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$"},"resourceType":{"type":"string","enum":["OPTION_SET","CART","PRODUCT_DATA_GRID"],"description":"The resource whose records carry this custom field."},"key":{"type":"string"},"name":{"anyOf":[{"anyOf":[{"type":"string"},{"type":"object","propertyNames":{"type":"string"},"additionalProperties":{"type":"string"}}]},{"type":"null"}],"description":"Translated text when `lang` is set, otherwise the full `{ language: text }` map. Languages with no text are omitted, and a field with no text at all is null."},"description":{"anyOf":[{"anyOf":[{"type":"string"},{"type":"object","propertyNames":{"type":"string"},"additionalProperties":{"type":"string"}}]},{"type":"null"}],"description":"Translated text when `lang` is set, otherwise the full `{ language: text }` map. Languages with no text are omitted, and a field with no text at all is null."},"type":{"type":"string","enum":["TEXT","NUMBER","TRANSLATABLE_TEXT","MULTI_LINE_TRANSLATABLE_TEXT","CHECKBOX","SINGLE_SELECT","MULTI_LINE_TEXT","FILE","META_OBJECT"]},"source":{"type":"string","enum":["SYSTEM","CUSTOM"]},"status":{"type":"string","enum":["ACTIVE","INACTIVE"]},"validationConfig":{"type":"object","properties":{"min":{"type":"number","minimum":0},"max":{"type":"number","minimum":0},"decimalPlaces":{"type":"integer","minimum":0,"maximum":9007199254740991},"regexExpression":{"type":"string"},"validationMessage":{"anyOf":[{"anyOf":[{"type":"string"},{"type":"object","propertyNames":{"type":"string"},"additionalProperties":{"type":"string"}}]},{"type":"null"}],"description":"Translated text when `lang` is set, otherwise the full `{ language: text }` map. Languages with no text are omitted, and a field with no text at all is null."},"isRequired":{"type":"boolean"},"isUnique":{"type":"boolean"},"showOnFrontend":{"type":"boolean"}},"additionalProperties":false},"typeConfig":{"anyOf":[{"type":"object","properties":{"checkboxContent":{"type":"object","properties":{"showInFooter":{"type":"boolean"},"content":{},"checkedLabel":{"anyOf":[{"anyOf":[{"type":"string"},{"type":"object","propertyNames":{"type":"string"},"additionalProperties":{"type":"string"}}]},{"type":"null"}],"description":"Translated text when `lang` is set, otherwise the full `{ language: text }` map. Languages with no text are omitted, and a field with no text at all is null."},"uncheckedLabel":{"anyOf":[{"anyOf":[{"type":"string"},{"type":"object","propertyNames":{"type":"string"},"additionalProperties":{"type":"string"}}]},{"type":"null"}],"description":"Translated text when `lang` is set, otherwise the full `{ language: text }` map. Languages with no text are omitted, and a field with no text at all is null."}},"required":["content","checkedLabel","uncheckedLabel"],"additionalProperties":false},"selectOptions":{"type":"array","items":{"type":"object","properties":{"id":{"type":"string"},"name":{"anyOf":[{"anyOf":[{"type":"string"},{"type":"object","propertyNames":{"type":"string"},"additionalProperties":{"type":"string"}}]},{"type":"null"}],"description":"Translated text when `lang` is set, otherwise the full `{ language: text }` map. Languages with no text are omitted, and a field with no text at all is null."},"value":{"type":"string"}},"required":["id","name","value"],"additionalProperties":false}},"fileContent":{"type":"object","properties":{"fileLimit":{"type":"string","enum":["SINGLE_FILE","MULTIPLE_FILE"]},"minFiles":{"type":"number"},"maxFiles":{"type":"number"},"fileTypes":{"type":"object","properties":{"acceptAllFileTypes":{"type":"boolean"},"images":{"type":"boolean"},"videos":{"type":"boolean"},"documents":{"type":"boolean"},"archives":{"type":"boolean"}},"additionalProperties":false},"fileExceptions":{"type":"object","properties":{"allowAdditionalFileTypes":{"type":"array","items":{"type":"string"}},"blockSpecificFileTypes":{"type":"array","items":{"type":"string"}}},"additionalProperties":false}},"required":["fileLimit"],"additionalProperties":false},"metaObjectContent":{"type":"array","items":{"type":"object","properties":{"parameterId":{"type":"string","pattern":"^PARAM-[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$"},"key":{"type":"string","minLength":1,"pattern":"^[a-zA-Z0-9-_]+$"},"type":{"type":"string","enum":["TEXT","NUMBER","TRANSLATABLE_TEXT","MULTI_LINE_TRANSLATABLE_TEXT","CHECKBOX","SINGLE_SELECT","MULTI_LINE_TEXT","FILE"]},"name":{"anyOf":[{"anyOf":[{"type":"string"},{"type":"object","propertyNames":{"type":"string"},"additionalProperties":{"type":"string"}}]},{"type":"null"}],"description":"Translated text when `lang` is set, otherwise the full `{ language: text }` map. Languages with no text are omitted, and a field with no text at all is null."},"description":{"anyOf":[{"anyOf":[{"type":"string"},{"type":"object","propertyNames":{"type":"string"},"additionalProperties":{"type":"string"}}]},{"type":"null"}],"description":"Translated text when `lang` is set, otherwise the full `{ language: text }` map. Languages with no text are omitted, and a field with no text at all is null."},"validationConfig":{"type":"object","properties":{"min":{"type":"number","minimum":0},"max":{"type":"number","minimum":0},"decimalPlaces":{"type":"integer","minimum":0,"maximum":9007199254740991},"regexExpression":{"type":"string"},"validationMessage":{"anyOf":[{"anyOf":[{"type":"string"},{"type":"object","propertyNames":{"type":"string"},"additionalProperties":{"type":"string"}}]},{"type":"null"}],"description":"Translated text when `lang` is set, otherwise the full `{ language: text }` map. Languages with no text are omitted, and a field with no text at all is null."},"isRequired":{"type":"boolean"},"isUnique":{"type":"boolean"},"showOnFrontend":{"type":"boolean"}},"additionalProperties":false},"typeConfig":{"type":"object","properties":{"checkboxContent":{"type":"object","properties":{"showInFooter":{"type":"boolean"},"content":{},"checkedLabel":{"anyOf":[{"anyOf":[{"type":"string"},{"type":"object","propertyNames":{"type":"string"},"additionalProperties":{"type":"string"}}]},{"type":"null"}],"description":"Translated text when `lang` is set, otherwise the full `{ language: text }` map. Languages with no text are omitted, and a field with no text at all is null."},"uncheckedLabel":{"anyOf":[{"anyOf":[{"type":"string"},{"type":"object","propertyNames":{"type":"string"},"additionalProperties":{"type":"string"}}]},{"type":"null"}],"description":"Translated text when `lang` is set, otherwise the full `{ language: text }` map. Languages with no text are omitted, and a field with no text at all is null."}},"required":["content","checkedLabel","uncheckedLabel"],"additionalProperties":false},"selectOptions":{"type":"array","items":{"type":"object","properties":{"id":{"type":"string"},"name":{"anyOf":[{"anyOf":[{"type":"string"},{"type":"object","propertyNames":{"type":"string"},"additionalProperties":{"type":"string"}}]},{"type":"null"}],"description":"Translated text when `lang` is set, otherwise the full `{ language: text }` map. Languages with no text are omitted, and a field with no text at all is null."},"value":{"type":"string"}},"required":["id","name","value"],"additionalProperties":false}},"fileContent":{"type":"object","properties":{"fileLimit":{"type":"string","enum":["SINGLE_FILE","MULTIPLE_FILE"]},"minFiles":{"type":"number"},"maxFiles":{"type":"number"},"fileTypes":{"type":"object","properties":{"acceptAllFileTypes":{"type":"boolean"},"images":{"type":"boolean"},"videos":{"type":"boolean"},"documents":{"type":"boolean"},"archives":{"type":"boolean"}},"additionalProperties":false},"fileExceptions":{"type":"object","properties":{"allowAdditionalFileTypes":{"type":"array","items":{"type":"string"}},"blockSpecificFileTypes":{"type":"array","items":{"type":"string"}}},"additionalProperties":false}},"required":["fileLimit"],"additionalProperties":false}},"additionalProperties":false}},"required":["parameterId","key","type","name","validationConfig"],"additionalProperties":false}}},"additionalProperties":false},{"type":"null"}]},"createdAt":{"anyOf":[{"type":"string"},{"type":"null"}],"description":"ISO 8601 creation timestamp."},"modifiedAt":{"anyOf":[{"type":"string"},{"type":"null"}],"description":"ISO 8601 last-modified timestamp."}},"required":["parameterId","resourceType","key","name","description","type","source","status","validationConfig","typeConfig","createdAt","modifiedAt"],"additionalProperties":false}}},"required":["data"],"additionalProperties":false,"description":"Data schema used by List Custom Fields (GET /v1/custom-fields). Read that operation for usage, permissions and update rules. Required fields and allowed values are defined below; request and response shapes can differ."},"PublicError":{"description":"An API error response. Use code and the HTTP status to classify the failure, message and optional details for context, and requestId when reporting it. Edge firewall responses may omit requestId.","type":"object","required":["code","message"],"properties":{"code":{"type":"string"},"message":{"type":"string"},"requestId":{"type":"string","description":"Present on every error the API itself returns; absent when the edge firewall rejected the request."},"details":{"description":"Optional error-specific details (e.g. per-field validation reasons)."}}}}},"paths":{"/v1/custom-fields":{"get":{"summary":"List Custom Fields","tags":["Custom Fields"],"description":"List custom-field definitions for the requested `resourceType`, including system parameters.\n\nUse `resourceType` to discover the definition keys and data types for one kind of record before reading or changing a field.\n\n## Behaviour\n\nLocalized fields are translated to `lang` when supplied.\n\nRequires the `customFields:read` scope.","responses":{"200":{"description":"Successful response.","headers":{"RateLimit-Limit":{"description":"Requests that can be admitted at once (the tier burst).","schema":{"type":"integer"}},"RateLimit-Remaining":{"description":"Tokens left after this request.","schema":{"type":"integer"}},"RateLimit-Reset":{"description":"Seconds until the bucket is full again.","schema":{"type":"integer"}}},"content":{"application/json":{"schema":{"$ref":"#/components/schemas/CustomFieldsList"}}}},"400":{"description":"Invalid request data.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/PublicError"}}},"headers":{"RateLimit-Limit":{"description":"Requests that can be admitted at once (the tier burst).","schema":{"type":"integer"}},"RateLimit-Remaining":{"description":"Tokens left after this request.","schema":{"type":"integer"}},"RateLimit-Reset":{"description":"Seconds until the bucket is full again.","schema":{"type":"integer"}}}},"401":{"description":"Missing or invalid API key.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/PublicError"}}}},"403":{"description":"The API key lacks the required scope (`scope_denied`), or the operation is not permitted for this account (`operation_not_permitted`).","content":{"application/json":{"schema":{"$ref":"#/components/schemas/PublicError"}}},"headers":{"RateLimit-Limit":{"description":"Requests that can be admitted at once (the tier burst).","schema":{"type":"integer"}},"RateLimit-Remaining":{"description":"Tokens left after this request.","schema":{"type":"integer"}},"RateLimit-Reset":{"description":"Seconds until the bucket is full again.","schema":{"type":"integer"}}}},"429":{"description":"The API key exceeded its request rate (`rate_limit_exceeded`) or its monthly quota (`quota_exceeded`). Both carry `Retry-After`; the `RateLimit-*` headers accompany `rate_limit_exceeded` only, since a spent quota says nothing about the bucket.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/PublicError"}}},"headers":{"Retry-After":{"description":"Seconds to wait before retrying.","schema":{"type":"integer"}},"RateLimit-Limit":{"description":"Requests that can be admitted at once (the tier burst).","schema":{"type":"integer"}},"RateLimit-Remaining":{"description":"Tokens left after this request.","schema":{"type":"integer"}},"RateLimit-Reset":{"description":"Seconds until the bucket is full again.","schema":{"type":"integer"}}}},"500":{"description":"Internal server error.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/PublicError"}}},"headers":{"RateLimit-Limit":{"description":"Requests that can be admitted at once (the tier burst).","schema":{"type":"integer"}},"RateLimit-Remaining":{"description":"Tokens left after this request.","schema":{"type":"integer"}},"RateLimit-Reset":{"description":"Seconds until the bucket is full again.","schema":{"type":"integer"}}}}},"parameters":[{"name":"resourceType","in":"query","required":true,"schema":{"type":"string","enum":["OPTION_SET","CART","PRODUCT_DATA_GRID"],"description":"The resource whose records carry this custom field."}},{"name":"lang","in":"query","required":false,"schema":{"type":"string","minLength":2,"maxLength":10,"description":"Language code to translate localized fields to (falls back if unavailable)."}}]}}}}
```


---

# Agent Instructions
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## Querying This Documentation
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Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://help.mimeeq.com/api/custom-fields/list-custom-fields.md?ask=<question>&goal=<user_goal>
```

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