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

# Update subscriber's custom attributes

Update the custom attributes of an SMS subscriber identified by phone number. Only the custom attributes included in the request are modified; attributes that are not provided remain unchanged.

```json
{"openapi":"3.1.0","info":{"title":"Recart API","version":"2023-12"},"tags":[{"name":"Subscriber","description":"Subscribers"}],"servers":[{"url":"https://api.recart.com/app-integrations/2023-12","description":"Production"}],"security":[{"ApiKeyAuth":[]}],"components":{"securitySchemes":{"ApiKeyAuth":{"type":"apiKey","in":"header","name":"X-Recart-API-Key","description":"It can be obtained in Recart account after contacting Support"}},"schemas":{"PatchSubscriber":{"type":"object","required":["type","attributes"],"properties":{"type":{"type":"string","enum":["subscribers"]},"attributes":{"type":"object","description":"Attributes of the subscriber to update","required":["customAttributes"],"properties":{"customAttributes":{"type":"object","description":"Merchant-defined custom attributes as key/value pairs. PATCH/merge semantics: keys included in the request are set or overwritten; a key with a `null` value is deleted; keys not included are left unchanged.\n\nLimits: maximum 30 attributes per subscriber; the entire `customAttributes` object must not exceed 16 KB (enforced by the API server). Keys must match `^(?!recart_)[A-Za-z][A-Za-z0-9_]{0,63}$` (start with a letter, alphanumeric or underscore, max 64 characters, no spaces; the `recart_` prefix is reserved). Values must be a string (max 1024 characters), number, boolean, an array of up to 100 strings (each max 255 characters), or `null` to delete the attribute. Nested objects are not allowed.\n","maxProperties":30,"propertyNames":{"pattern":"^(?!recart_)[A-Za-z][A-Za-z0-9_]{0,63}$"},"additionalProperties":{"oneOf":[{"type":"string","maxLength":1024},{"type":"number"},{"type":"boolean"},{"type":"array","maxItems":100,"items":{"type":"string","maxLength":255}},{"type":"null"}]}}}}}},"HttpErrorBody":{"type":"object","required":["errors"],"properties":{"errors":{"type":"array","items":{"type":"object","required":["id","code","title","detail"],"properties":{"id":{"type":"string"},"code":{"type":"string"},"title":{"type":"string"},"detail":{"type":"string"}}}}}}},"responses":{"HttpError":{"description":"HTTP Error response","content":{"application/vnd.api+json":{"schema":{"$ref":"#/components/schemas/HttpErrorBody"}}}}}},"paths":{"/subscribers":{"patch":{"summary":"Update subscriber's custom attributes","tags":["Subscriber"],"operationId":"patchSubscriber","description":"Update the custom attributes of an SMS subscriber identified by phone number. Only the custom attributes included in the request are modified; attributes that are not provided remain unchanged.\n","parameters":[{"name":"phoneNumber","in":"query","required":true,"description":"Phone number of the subscriber","schema":{"type":"string"}}],"requestBody":{"required":true,"content":{"application/vnd.api+json":{"schema":{"type":"object","properties":{"data":{"$ref":"#/components/schemas/PatchSubscriber"}}}}}},"responses":{"204":{"description":"No content"},"4XX":{"$ref":"#/components/responses/HttpError"},"5XX":{"$ref":"#/components/responses/HttpError"}}}}}}
```


---

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