The honest answer about Roblox's filter — what gets hashed into # symbols, what shows as boxes, and the one configuration that sometimes slips through.
Partially — and less every year. Roblox filters combining marks aggressively: heavy zalgo becomes ##### or boxes (□) in chat, and usernames can't contain it at all. Very light zalgo — one or two marks per letter, above and below only, never through the middle — sometimes passes in chat, but it varies by experience and is never guaranteed. If you want a corrupted look on Roblox, generate the lightest possible version and test it in-game before committing.
Roblox's chat filter is designed to catch filter evasion and disruptive text, and a run of stacked combining marks looks exactly like both. When the filter can't verify text as safe, it replaces it with # symbols. Marks that survive the filter can still fail at the rendering stage — Roblox's fonts don't support every combining mark, so survivors often show as boxes.
Middle (overlay) marks are the first to die. Strikethrough-style marks that cross through letters are both the most aggressively filtered and the most likely to render as boxes on players' devices. Whatever you try, leave the middle position off.
Usernames: impossible. Roblox usernames accept letters, numbers, and one underscore — combining marks are rejected when you create or change a name.
Display names: stricter than chat. Some Unicode passes, but zalgo stacks are rejected or rendered as boxes for other players. If a glitchy identity is the goal, a display name that hints at corruption (a single mark, or a substitution font) outlives anything heavier.
Plain-substitution Unicode fonts (bold, gothic, bubble and similar) are separate characters rather than stacked marks, so the filter treats them like normal text far more often — they're the reliable way to stand out on Roblox. See how to change your Roblox username for the naming rules, and which symbols game usernames allow for what passes in other games too.
The Subtle preset + Up & Down position is the best-chance Roblox recipe — one click, then test in-game.
Open the Zalgo Text Generator →Related: worried a zalgo message could be dangerous? See is zalgo text safe. Received corrupted text you can't read? Here's how to remove zalgo.