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Mark spoilers on Reddit posts (web and apps)

User guide · Updated Nov 6, 2026 · about 3 minutes to read

Blur thumbnails and hide previews so readers choose when to reveal plot-heavy posts.

SubMouse Editorial guide — independent and not affiliated with Reddit. Steps cite public Reddit Help pages; menu labels can change.

What a spoiler tag does

A spoiler tag labels a post so readers can decide before they see the content. Reddit Help states that a spoiler-tagged post shows a SPOILER label, blurs its thumbnail, and hides the preview until someone clicks to reveal it.

The original poster can add the tag while creating the post. Moderators can also mark a post as a spoiler after it is live, if the community has the spoiler setting enabled.

When to use it

Use a spoiler tag when the title or thumbnail alone would ruin a book, show, game, or other plot for someone who is not caught up. Prefer a neutral title plus the tag instead of packing the twist into the title.

  • Good fit: episode discussion, ending reactions, major game story reveals.
  • Poor fit: everyday tips or news with no surprise to protect.
  • Still follow the community’s rules — some rooms require spoilers for a window of time; others ban certain spoilers entirely.

Hypothetical: you finished a series finale and want to talk about the last scene. Title it without the twist, turn Spoiler on, and put the reveal in the body so a scrolling reader is not spoiled from the feed alone.

Mark a spoiler while posting (web)

  1. Go to create a post on reddit.com.
  2. Click Add flair and tags.
  3. Move the Spoiler slider to on.
  4. Finish the post and click Post.

Reddit’s posting Help also notes you can mark NSFW or add a spoiler when the content may ruin a surprise. Community rules still decide whether that post belongs there at all.

Mark a spoiler while posting (apps)

  1. Tap Create to make a post on iOS or Android.
  2. Tap the Add tags and flair option.
  3. Tap the Spoiler slider to on.
  4. Tap Post when the rest of the draft is ready.

On some app flows, tags sit under the overflow menu after you start the draft — look for Spoiler next to other post tags rather than inventing a different path.

Title words that auto-tag

Reddit Help documents automatic spoiler tagging when a title contains “spoiler” or “spoilers.” Titles that contain “no spoiler” or “no spoilers” are not auto-tagged. The same pattern applies to NSFW wording.

Do not rely on auto-tag alone. If the body or thumbnail can spoil someone, turn the Spoiler slider on explicitly.

If you moderate the community

Before mods can mark posts as spoilers, the community setting must allow it. On desktop Mod Tools, open Post & Comments under settings and enable the Spoiler tag toggle. Reddit Help notes that enabling is desktop-configured, then works on desktop and mobile afterward.

To mark a live post: open the mod shield (or overflow with mod mode on) and choose the spoiler action (Help lists “Mark as spoiler” / “Add spoiler tag” depending on surface).

Quick checklist

  • Does the feed preview or thumbnail give away a plot point? → Spoiler on.
  • Is the title itself the spoiler? → Rewrite the title; keep the reveal in the body.
  • Does this community require spoilers for a release window? → Follow that rule even if you think everyone is caught up.
  • Are you a mod cleaning up an unmarked reveal? → Confirm Spoiler tag is enabled in Post & Comments, then mark the post.

Related on SubMouse

  • Choosing where to post → article How to choose which subreddit to post in.
  • What moderators can do in general → article Reddit moderators explained.
  • Reporting a post that breaks rules → guide Report, block, and mute.

More on SubMouse

Reddit Help sources