Username Rules by Platform: The 2026 Cheat-Sheet

The biggest source of username friction isn't taste — it's hitting a platform's hidden rule (Twitter's 15-char cap; Roblox's letters-only-start; Snapchat's no-trailing-period). Here's the current rule set for every major service, as of early 2026.

The big six

Instagram

• 1–30 characters.
• Lowercase letters, digits, periods, underscores.
• No leading or trailing periods. No double periods.

TikTok

• 2–24 characters.
• Lowercase letters, digits, periods, underscores.
• Periods allowed mid-word but not at the start or end.

Twitter / X

• 4–15 characters — the tightest cap of any major platform.
• Letters, digits, underscores only. No periods. No hyphens.
• Case-insensitive but displays however you set it.

Discord

• 2–32 characters.
• Lowercase letters, digits, periods, underscores (post-2023 update).
• Display name is separate and accepts almost anything.

Roblox

• 3–20 characters.
• Letters, digits, underscore.
• Must start with a letter — this is the one most people forget.
• Underscores allowed but only one, and not at the start or end.

Minecraft (Java)

• 3–16 characters.
• Letters, digits, underscore only.
• Case is preserved on display but irrelevant for the actual identifier.

Console / gaming

Xbox (gamertag)

• 3–12 characters in the free format.
• Letters, digits, one internal space allowed.
• Premium / branded gamertags can go longer but cost money.

PlayStation

• 3–16 characters.
• Letters, digits, underscore, hyphen.
• Must start with a letter.

Steam

• 2–32 characters for the custom URL / vanity ID.
• Letters, digits, period, underscore, hyphen.
• Display name is completely free-form — change as often as you want.

Picking one that works everywhere

If you want a handle that's identical across every major platform, the binding constraint is Twitter's 15-char letters-digits-underscore-only rule. Stay under 15 characters, no periods, no hyphens, must work with Roblox's must-start-with-a-letter rule on top — and you have a handle that survives every signup form.

Start where you actually live

There's no penalty for picking a name optimised for your main platform rather than for all of them. Our generators auto-respect each platform's rules: