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Messaging identity and contact linkage

Signal usernames, phone numbers and identity links

A Signal username can start contact without sharing a phone number. Existing chats, profile details and verification still affect what the other person can connect.

Sources checked .

Conceptual illustration

A username is a contact route, not the displayed profile name

Signal describes usernames as optional ways to initiate contact without sharing a phone number. A phone number is still required to register, and the username differs from the profile name shown in chats. Signal: usernames, existing chats and phone-number settings

Number visibility and number discovery are separate controls

Signal provides one setting for showing the number and another for finding an account by searching the number. Restricting discovery can make it harder for known contacts to start a conversation. Signal: phone-number privacy, usernames and chat linkage

Existing number and username conversations can merge

Signal says an existing phone-number chat can merge with a later username conversation, revealing that both routes reach the same person. Its FAQ says this can happen even when number discovery is restricted. Signal: phone-number privacy, usernames and chat linkage

Changing a username does not end existing chats

Signal says creating, changing or deleting a username does not notify contacts or groups. Changing or deleting it does not affect conversations already established through the earlier username. Signal: usernames, existing chats and phone-number settings

A profile label is not a verified real-world identity

Signal states that it does not verify profile names or identities. A familiar displayed name should not establish who controls an account. Signal: profile identity, blocking and recipient copies

Key verification has a different purpose

Signal says automatic key verification depends on having a contact's phone number and may be unavailable for username-based contact. Its absence does not establish a compromised chat. The feature checks encryption keys, not real-world identity. Signal: key verification availability and identity limits

Questions and answers

Does a username remove the phone-number registration requirement?

Signal says a phone number is still required. Signal: usernames, existing chats and phone-number settings

Does a username make an existing number conversation unrelated?

Signal says the conversations can merge. Signal: phone-number privacy, usernames and chat linkage

Does automatic key verification certify a person's identity?

Signal says it does not verify real-world identity. Signal: key verification availability and identity limits

Sources and scope

Signal's public help checked 10-24-2026. Signal's help pages conflict about number visibility to saved contacts. A number someone already knows should not be treated as erased. Username chat linkage and key-verification limits are provider descriptions, not independent traffic or account tests.

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