Alt text
Alt text is a short text description of an image, read by screen readers and shown when an image fails to load. Adding it improves accessibility and can also help with SEO.
Adding alt text in the composer
- Attach an image.
- Click the image preview in the composer.
- Enter the description in the Alt text field.
Per-channel alt text is supported — different networks allow different lengths, and you may want a shorter version for one and longer for another.
Network support
| Network | Alt text via API | Notes |
|---|---|---|
| Twitter / X | Yes | Up to 1,000 chars |
| Yes | Up to 1,000 chars | |
| Yes (Pages) | ||
| Yes | Up to 100 chars recommended | |
| Threads | Yes | |
| Bluesky | Yes | |
| Yes | Combined with the description for SEO | |
| TikTok | No | Not exposed by API |
| Google Business Profile | No | |
| No | ||
| YouTube | N/A | Doesn't apply to thumbnails |
For networks that don't support alt text, the field is hidden in the composer.
Tips for good alt text
- Describe what's relevant. A photo of a coffee cup on a desk during a launch announcement: "Coffee mug branded with our new logo, sitting on a wooden desk."
- Skip the redundant. Don't write "image of" or "picture of" — screen readers already announce that.
- Match the post intent. If the visual makes a point the caption builds on, describe the visual specifically.
- Keep it short. One or two sentences is plenty.