Medium can present the same profile at an @username address, a username subdomain, and a custom domain. Treat these as address formats rather than identity checks: a custom domain shows how the owner chose to publish, not who they are. Record which forms you actually saw, note any username change as a separate event, and keep the map dated to your own observations.
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Start with the three formats you may see
Medium supports an @username profile address, a username subdomain, and a custom-domain profile address. The practical move is to copy each address exactly as it appears, note where you found it, and mark whether the page opened. Do not assume one form is more official than another; they are supported ways to reach a profile, and the owner may use more than one. [Medium Help: profile URL schemes and username changes]
- Copy the address exactly, including any prefix or subdomain
- Note the page or artifact where you found it and the date you checked
Separate a scheme change from a username change
These are different events and should sit in different notes. A scheme change is the same named profile reached through a different supported address form, such as enabling a subdomain, which redirects the earlier profile and story address scheme. A username change is a change of handle: the old profile link stops showing the profile, old story addresses redirect, and earlier mentions still point at the profile. Mixing the two creates a false story about a person changing names when only the address format changed. [Medium Help: profile URL schemes and username changes]
- Log scheme changes as an address observation
- Log username changes as a handle observation with the date you noticed it
Build a one-profile map you can defend
Use a small table with one row per address you actually saw. Keep the observation column factual, the limit column honest, and the next step modest.
- Keep the map small and add a date to every row
- Delete or correct rows you cannot re-check
| observation | limit | next step |
|---|---|---|
| An @name address was published on a public profile | Shows a supported address form; does not confirm who runs it | Re-check the same public page later and date the note |
| A username subdomain opened the same visible profile | Consistent with one profile using another supported form | Record it as a scheme observation, not a new person |
| A custom domain opened what looks like the same profile | A custom domain is a publishing choice, not verification | Keep it as one mapped address and do not upgrade it to proof |
| The handle in an older mention differs from the current one | Consistent with a username change leaving old mentions intact | Note the change separately and avoid merging the two handles without context |
Why a custom domain is not identity verification
A custom domain can point a reader to a Medium profile, but the setup itself does not establish who is behind the profile. Treat it as one more supported address, not a badge of authenticity. The same caution applies to a matching photo, a filled bio, or a privacy setting; each is an observation with limits, not proof of identity, intent, or current activity.
- Use neutral wording such as appears to be the same profile
- Avoid words like verified, confirmed, or official unless a source says so
Decide what the map is for before adding rows
A one-profile map is useful when you need to follow an author across address formats, cite a stable public link, or check whether two public addresses resolve to the same visible profile. It is not useful for guessing at private accounts or inferring intent. Write down the decision the map supports, then stop once the map answers that question. [Medium Help: profile URL schemes and username changes]
- State the decision in one sentence before collecting anything
- Stop when no new address form appears in the permitted material
When something is unavailable, stop at the boundary
If a documented control or a permitted public artifact is not available, record it as unavailable and stop. Do not substitute a guess, a similarity match, or a workaround. The safer route is to check the official current help for that feature or ask the owner for a voluntary current link, and then resume only with what they choose to share. [Medium Help: profile URL schemes and username changes]
- Write unavailable next to the row rather than leaving it blank
- Never fill a gap with a matching image or an assumed handle
A couple more questions
Does a custom domain prove the same person runs an @name and a subdomain profile?
No. A custom domain is one supported address form, and seeing similar content across forms is an observation with limits, not confirmation that one person controls every address. Map them as separate addresses unless the public material gives you a clear reason to link them.
How do I record a username change without confusing it with a subdomain switch?
Put the handle change in its own row and note that the old profile link no longer shows the profile while old story addresses and earlier mentions may still point at it. Record the subdomain switch separately as an address-format observation on the same profile.
What if the address I found no longer opens a profile?
Note it as unavailable and stop at that boundary. Check the official current help or ask the owner for a voluntary current link rather than guessing at a replacement handle.
Should a matching profile photo strengthen my map?
It can be listed as an observation, but it is not identity proof. Keep it in the limit column and avoid treating visual similarity as confirmation, especially when building a map from public material only.
Sources & editorial notes
Official references checked on October 23, 2026. Checklists, comparison tables and example wording are DateClues editorial tools, not official tests or validated risk scores.
General information. No guide or tool can certify a person’s identity, intentions or safety. Read our editorial standards.