What does a phone number reveal on Signal?
Whether an account is registered, at most, and only from inside the app.
Signal's privacy policy puts the registration plainly: "You register a phone number when you create a Signal account." It adds that contact information "may be cryptographically hashed and transmitted to the server in order to determine which of your contacts are registered", which is the whole of the discovery mechanism.
The support article on the subject is blunter still. "Registration notifications are never transmitted by anyone in any direction at all; these notifications are created by your phone." People already holding your number simply see that they can now message you there.
So there is no Signal equivalent of a wa.me or a t.me address. Nothing resolves in a browser, and the confirmation a number gives you is a line in your own app that nobody else sees.
Which setting decides whether your number finds you?
Two settings, and the second of them is the only thing between a number and a confirmation.
Signal's phone number privacy article names them as Who can see my number and Who can find me by my number. The second, it says, "determines whether someone is able to see that they can message you on Signal by searching for your phone number". The default is already narrow: a number is "not visible in your profile details page to people who don't already have it saved".
The two are coupled by design. To set finding to Nobody you must first set seeing to Nobody, and then, in Signal's words, "nobody can find you on Signal unless you message them or they have an existing chat with you".
Saved numbers stay visible. Signal is explicit that people who have your number saved in their own contacts will still see it whatever you choose, because they already knew it. The settings govern strangers, not the address books you are already in.
What does a Signal username expose?
Far less than a username exposes anywhere else, and Signal said so in the sentence that introduced them.
The announcement of 20 February 2024 describes them as "not logins or handles that you'll be known by on the app – they're simply a quick way to connect without sharing a phone number". The same post states that Signal "does not provide a searchable directory of usernames", so an exact string is the only way in.
The support article adds that a username "does not appear in your profile details", and that the format runs from three to 32 characters, lower-case letters, digits and underscores only, with at least two digits on the end.
They are also not property. Signal says a username cannot be transferred or held for somebody else, and that once you change yours "anyone can claim it soon" — the opposite of Telegram's collectible handles.
The profile is a name the owner typed. Signal's servers cannot read it, and nothing checks it against anybody.
The profile name is not a verified identity
It is a string the owner typed, and Signal's own servers cannot read it.
The profiles article defines it as "a name and picture that you set up within the app", with a first name required and the photo and last name optional. On what the service knows it is categorical: "The Signal service does not have any knowledge of the name you have chosen or the image you have set."
That is why there is nothing to search. The profile is end-to-end encrypted under a profile key, shared with your saved contacts, with people and groups whose conversations you create, and with anybody whose message request you accept.
Read a new one accordingly. A warm name and a friendly photograph arriving with a message request cost the sender nothing, and a reverse image search is worth more than either of them.
What does sealed sender mean for metadata?
That Signal stopped writing the sender's address on the outside of the envelope. The change is aimed at the service rather than at a stranger.
The announcement of 29 October 2018 starts from what is already absent, saying the service "does not store a record of your contacts, social graph, conversation list, location, user avatar, user profile name, group memberships, group titles, or group avatars". Sealed sender goes after the next item, "hiding another piece of metadata: who is messaging whom".
The mechanism has two halves. A short-lived sender certificate attests to the sender for the recipient, and a delivery token derived from the profile key stops the feature becoming an open spam channel.
The limit is in the same post. Signal writes that the service "always needs to know where a message should be delivered", so the destination stays visible even when the origin does not.
What does verifying a safety number prove?
That the channel has not been tampered with. Signal adds in the same breath that it "does not verify anyone's identity".
The support article gives each one-to-one chat its own safety number and says comparing it verifies "the security of your messages and calls with specific contacts", ideally by scanning the other person's QR code in person. Marking it verified applies "on your side only".
A change alert is not evidence of an attack either. Signal names a contact switching to a new device or reinstalling as the common causes, and notes that "these actions don't always result in a safety number change".
So the verified tick answers a narrow question well. It says the key you are encrypting to is the key you checked, and nothing whatever about who is holding the device.
Signal, WhatsApp and Telegram publish different things
All three register accounts to a phone number, and then they diverge completely on what a stranger is handed.
WhatsApp's documented defaults give any user your profile photo and online status, which is why a wa.me link and the profile behind it settle so much. Telegram publishes a handle that opens in any browser together with whatever public channels sit behind it. Signal publishes a name the owner typed, to people the owner accepted.
| App | Readable without contact | Where it is readable | What it will not give |
|---|---|---|---|
| Profile photo and online status | The app, once a wa.me link opens a chat | About text and last seen, which default to contacts | |
| Telegram | Display name, photo, bio, public channels | Any browser, at t.me/handle | The number, and any account creation date |
| Signal | Whether the number is registered, at most | The app, and only if the owner's setting allows | Profile name, photo and username |
Read the third row as the finding it is. An empty result on Signal describes the platform rather than the person.
A grand jury asked, and Signal had almost nothing
Signal publishes the legal demands it receives, and the most recent of them measures the gap precisely.
A grand jury subpoena from the United States District Court for the District of Columbia, published on 6 March 2026 and read here on 4 August 2026, asked for the account creation date and time and the last connection date and time for a list of 37 numbers.
Signal's response was short. Seven of those accounts did not exist, for 24 there was no responsive information for the period at issue, and for the remaining six the dates were produced. Signal's framing of why is the line worth keeping: it cannot share data "in response to valid legal requests that we never had in the first place".
The limit matters as much as the result. That describes what Signal's servers hold, not what a device holds, and an unlocked handset in somebody's possession is an entirely different problem.
Does a lookup here check Signal?
No, and there is nothing on Signal for it to check.
The DetectiveCheck phone module reaches 8 sources: the line's own validity, its carrier and line type, account-existence checks against PayPal, Binance and Facebook, and a sweep for public mentions, with Brazilian numbers additionally getting the region behind the area code, PicPay and Pix. Signal is not among them, and the phone lookup page lists what is.
The username module gives the same answer for the same reason. It reads 71 platforms, each of which exposes a profile at a predictable address, and Signal exposes none, so there is no directory to query.
What is worth running is the line itself and the person's other identifiers. Our reverse phone lookup guide covers the first, and an email address reaches 71 sources by comparison.
Common questions
Can you find someone's Signal account by phone number?
Only to the extent of learning that an account exists, and only from inside the app. Signal's Who can find me by my number setting determines whether a search by number shows that you can be messaged there. If it is set to Nobody, even people holding your number in their contacts will not see that you are on Signal.
Does Signal have a public profile page?
No. There is no Signal address that resolves in a browser, so there is no equivalent of a wa.me link or a t.me page to open. The profile name and picture are end-to-end encrypted and shared only with saved contacts, with conversations you create, and with people whose message request you accept.
Are Signal usernames searchable?
No. Signal's own announcement states that it does not provide a searchable directory of usernames, so somebody has to know your exact username, including the digits on the end, before they can start a chat with it. The username also does not appear in your profile details, so accepting a message request does not reveal it.
What are the rules for a Signal username?
Between three and 32 characters, using lower-case letters, digits and underscores only, with at least two digits required at the end. Usernames are case insensitive and you can hold one at a time. The trailing digits exist so that common names can be shared without anybody needing to claim a unique word.
Will the person know I searched for their number?
Not from the search itself. Signal states that registration notifications are never transmitted in any direction and are created by your own phone, so nothing reaches the other account. Sending a message request is different: they see your profile name and picture along with the request, before they decide anything.
What does a Signal safety number actually verify?
The encryption channel, not the person. Signal's support article says a safety number lets you verify the security of your messages and calls with a specific contact and immediately adds that this does not verify anyone's identity. Marking one as verified applies on your own side only and has no effect on theirs.
What is sealed sender on Signal?
A change that removes the sender's address from the outside of the message envelope, so the service handling delivery does not learn who is messaging whom. Signal announced it in October 2018. It does not hide the destination: the same post says the service always needs to know where a message should be delivered.
What does Signal give law enforcement?
Very little, and it publishes the demands. A 2026 grand jury subpoena from the District of Columbia asked only for account creation and last connection times; seven of the accounts named did not exist, 24 produced no responsive information, and six returned dates. Signal cannot share data it never held.
Can a Signal username be bought or transferred?
No. Signal states that you cannot transfer a username to another person or hold one for somebody else to claim, and that once you change yours anyone can claim it soon afterwards. That is the opposite of Telegram, where collectible handles are sold and reassigned, so a Signal username identifies nobody over time.
Does a DetectiveCheck lookup cover Signal?
No. The phone module reaches 8 sources, covering the line's validity, carrier and line type, account-existence checks against PayPal, Binance and Facebook, and a sweep for public mentions. Signal is not one of them and could not be, because it publishes no profile for any checker to read.
