We can use this api

It looks exactly what I'm looking for !
I dont understand how to use it on my form. I would like to display a personalized message

https://www.qualtrics.com/community/discussion/comment/30843#Comment_30843After the email question in survey flow, use web service to run the api. At the place of email addredd pipe text the email text entry question.

{
"method": "get",
"url": "https://ca1.qualtrics.com/API/v3/directories/POOL_6rreF5wyXus6pJr/contacts/search",
"query": {
"pageSize": "100"
},
"headers": {
"X-API-TOKEN": "masked"
},
"body": "{\\n \\"filter\\": {\\n \\"conjunction\\": \\"and\\",\\n \\"filters\\": [\\n {\\n \\"comparison\\": \\"eq\\",\\n \\"filterType\\": \\"email\\"\\n },\\n {\\n \\"comparison\\": \\"eq\\",\\n \\"filterType\\": \\"email\\"\\n }\\n ]\\n }\\n}"
}
{
"meta": {
"httpStatus": "403 - Forbidden",
"error": {
"errorMessage": "Your brand does not have access to this API endpoint.",
"errorCode": "AuthZ_2.0"
},
"requestId": "3a138976-0f07-412e-ae1a-9a6ea12d99ca",
"notice": "Request proxied. For faster response times, use this host instead: fra1.qualtrics.com"
}
}
did I do well ?

Check with your brand admin, and ask to enable this API.