When you share an image or video on Mastodon that contains nudity, violence, or spoilers, you want to warn viewers before they see it. Mastodon includes a built-in toggle that marks a post as containing sensitive media. This feature blurs the attached files and requires viewers to click through a warning before they can see the content. This article explains how to enable the sensitive media toggle on individual posts and what the feature does to protect your audience.
Key Takeaways: Mastodon Per-Post Sensitive Media Toggle
- Post composer > Mark media as sensitive checkbox: Blurs attached images and videos behind a content warning on the web and mobile apps.
- Preferences > Appearance > Mark media as sensitive by default: Automatically marks all future posts as sensitive without needing the per-post toggle.
- Content warning field in the composer: Hides the entire post text and media behind a warning label, distinct from the media-only toggle.
What the Sensitive Media Toggle Does and When to Use It
The sensitive media toggle is a checkbox that appears in the post composer on both the Mastodon web interface and mobile apps. When you check this box, any images or videos attached to that post are blurred in the timeline. Viewers see a warning label and must click to reveal the media. The toggle applies only to the current post, not to future posts.
This feature is separate from the Content Warning field. The Content Warning field hides the entire post text behind a clickable label. The sensitive media toggle only affects the visual media attachments. You can use both together: add a Content Warning for the text and check the media toggle for the images.
Use the sensitive media toggle when you post images that contain nudity, graphic violence, gore, or strong spoilers for movies, TV shows, or games. The toggle does not require moderator approval. You decide on each post whether to mark it as sensitive.
How the Blur Behaves for Different Users
When you mark a post as sensitive, users who follow you see the blurred media in their home timeline. If a user has the setting Always show media marked as sensitive enabled in their preferences, the media appears unblurred. If they have Hide media marked as sensitive enabled, the media stays blurred until they click. The per-post toggle respects each viewer’s personal preference.
How to Set the Sensitive Media Toggle on a Single Post
- Open the post composer
Click the compose button on the Mastodon web interface or tap the compose icon in the mobile app. The composer opens with a text area and attachment controls. - Attach one or more media files
Click the attachment icon (paperclip or camera) and select images or videos from your device. The files upload and appear as thumbnails below the text area. - Locate the sensitive media checkbox
Look directly below the media thumbnails. You see a checkbox labeled Mark media as sensitive. On the web interface, the checkbox appears next to each media thumbnail. On mobile, one checkbox applies to all attached media. - Check the box
Click or tap the checkbox. A checkmark appears. The media thumbnails remain visible to you while composing, but the post will be blurred for other users after publishing. - Optionally add a Content Warning
If you want to hide the post text as well, click the CW button above the text area. Type the warning label in the field that appears. The media toggle works independently of the Content Warning field. - Publish the post
Click the Publish button. The post appears in timelines with blurred media. Viewers see a banner that says Sensitive content and must click to reveal the images or videos.
Verifying the Toggle Worked After Publishing
After you publish, open your profile page and find the post. If the media is blurred and shows the sensitive content banner, the toggle worked. If you see the full image, you may have forgotten to check the box or your instance theme may override the blur. Check the post again in a private browser window to confirm the blur is applied for viewers who are not logged in.
What to Avoid and Limitations of the Per-Post Toggle
Accidentally Publishing Without the Toggle
If you forget to check the sensitive media box, the post publishes with visible media. You cannot edit the post later to add the toggle. Mastodon does not allow editing attachments after publishing. You must delete the post and create a new one with the toggle checked. Always double-check the checkbox before pressing Publish.
Confusing the Toggle with the Default Instance Setting
Some Mastodon server administrators enable a server-wide rule that marks all media as sensitive. If your instance has this rule, the per-post toggle may appear already checked. In that case, unchecking the box may not remove the sensitive label because the server overrides your choice. Check with your instance admin or look in Preferences > Appearance to see if the default is set.
Using the Toggle for Non-Media Content
The sensitive media toggle only affects attached images and videos. It does not blur links, polls, or text. If your post contains a link to sensitive material, use the Content Warning field instead. The Content Warning hides the entire post until the viewer clicks the warning label.
Mobile App Differences
On the official Mastodon mobile app for iOS and Android, the sensitive media checkbox appears below the media attachments after you add them. Third-party apps like Tusky or Mammoth may place the checkbox in a different location or label it differently. If you cannot find the checkbox, open the post in the official app or web interface to set the toggle.
| Item | Per-Post Toggle | Default Setting in Preferences |
|---|---|---|
| Scope | Only the current post | All future posts |
| How to access | Checkbox in the composer below media thumbnails | Preferences > Appearance > Mark media as sensitive |
| Override by server | Can be overridden if instance forces sensitive media | Respected unless server forces sensitive media |
| Works with Content Warning | Yes, independent | Yes, independent |
Comparison: Per-Post Toggle vs Default Setting vs Content Warning
The per-post sensitive media toggle is one of three ways to control how Mastodon displays potentially objectionable content. The table below compares the three methods.
| Feature | Per-Post Toggle | Default Setting | Content Warning |
|---|---|---|---|
| What it affects | Only attached media on the current post | All attached media on future posts | Entire post text and media |
| Where to set | Composer checkbox below media | Preferences > Appearance | CW button in composer |
| Can toggle be changed after posting | No | Yes, changes apply to future posts only | Yes, you can edit the Content Warning text after posting |
| Visibility for viewer | Media blurred, text visible | Media blurred, text visible | Entire post hidden behind a warning label |
Now you can use the per-post sensitive media toggle to blur images and videos on individual Mastodon posts. Check the box in the composer before publishing to warn viewers about nudity, violence, or spoilers. If you mark sensitive content often, enable the default setting in Preferences > Appearance to save time. Remember that you cannot edit the toggle after posting, so verify the checkbox is checked before you click Publish.
For posts that require hiding the entire message, use the Content Warning field instead of the media-only toggle. Combining both gives you full control over how your audience sees your content. To customize the behavior for your own timeline, adjust the settings in Preferences > Appearance > Hide media marked as sensitive or Always show media marked as sensitive.