The error

Property username is missing.

occurs because your identity schema likely requires the

username

field to be present in the traits, not just when creating but also when updating the profile. In Ory Kratos, the identity schema defines which fields are required for an identity. If

username

is marked as required in your schema, then every update to the profile (even if you only want to change the email) must include the

username

field in the payload, otherwise Kratos will reject the request with this error. For example, a schema like this:

json {   "properties": {     "traits": {       "type": "object",       "properties": {         "email": { "type": "string", "format": "email" },         "username": { "type": "string" }       },       "required": ["email", "username"],       "additionalProperties": false     }   } }

means both

email

and

username

are required. When you update, you must send both fields, even if you only want to change one of them. This is standard JSON Schema behavior and is enforced by Kratos during profile updates [Customize identity schemas: Examples](https://www.ory.sh/docs/kratos/manage-identities/customize-identity-schema#username-and-email-and-password). Solution: When updating the profile, always include all required fields from your identity schema in the

traits

object. For your case, the payload should look like:

json {   "csrf_token": "{{settingFlowCsrf}}",   "method": "profile",   "traits": {     "email": "<mailto:new-email@example.com|new-email@example.com>",     "username": "VNSuser001"   } }

If you do not want

username

to be required, you need to update your identity schema and remove

username

from the

required

array. Otherwise, you must always provide it in update requests [Customize identity schemas: Multiple identifiers](https://www.ory.sh/docs/kratos/manage-identities/customize-identity-schema#multiple-identifiers). Summary: Kratos enforces the identity schema on every update. All required fields must be present in the update payload, even if you are not changing them [Settings and profile updates](https://www.ory.sh/docs/kratos/self-service/flows/user-settings#settings-form-validation).

Yes, that's correct. If you remove username from the required array in your identity schema, then Ory Kratos will not require the username field when creating a new identity. Only the fields listed in the required array are mandatory during registration or identity creation. If username is not required, users can register without providing it [Mandatory fields for registration](https://www.ory.sh/docs/kratos/manage-identities/customize-identity-schema#mandatory-fields-for-registration).