Image Specs
Post Image
| Dimensions | Up to 4000 × 4000 px |
|---|---|
| Max File Size | 2 MB per image |
| File Formats | JPG, PNG, GIF, WEBP |
| Notes | Up to 4 images per post; GIF animations are supported |
Profile Photo
| Dimensions | 1000 × 1000 px recommended |
|---|---|
| Max File Size | 1 MB |
| File Formats | JPG, PNG, WEBP |
| Notes | Displayed as a circle |
Profile Banner
| Dimensions | 3000 × 1000 px recommended |
|---|---|
| Aspect Ratio | 3:1 |
| Max File Size | 1 MB |
| File Formats | JPG, PNG, WEBP |
[Ad]
Video Specs
Post Video
| Max File Size | 300 MB |
|---|---|
| File Formats | MP4 |
| Resolution | Up to 1920 × 1080 px |
| Max Duration | Up to 10 minutes |
| Notes | H.264 codec recommended; plays inline in the feed. File size raised from an earlier 100 MB cap to 300 MB, and duration raised from 3 to 10 minutes on Aug 25, 2026 |
Text & Character Limits
Post
| Character Limit | 300 characters |
|---|---|
| Notes | Links are shortened to the domain plus up to 16 characters of path, and the shortened text counts toward the 300 limit |
Bio
| Character Limit | 256 characters |
|---|
Display Name
| Character Limit | 64 characters |
|---|
Handle
| Character Limit | 253 characters |
|---|---|
| Notes | In the format user.bsky.social or a custom domain; 3 characters minimum |
Alt Text
| Character Limit | 2,000 characters |
|---|---|
| Notes | Alt text for images; strongly encouraged for accessibility. Client-enforced UI limit (not a protocol-level limit); raised from 1,000 characters |
Profile Links
| Character Limit | 10 links |
|---|---|
| Notes | Each link can have an optional title of up to 40 characters; launched Oct 22, 2026 |
Profile Assets
Avatar
| Dimensions | 1000 × 1000 px recommended |
|---|---|
| Max File Size | 1 MB |
| File Formats | JPG, PNG, WEBP |
| Notes | Displayed as a circle |
Banner
| Dimensions | 3000 × 1000 px |
|---|---|
| Aspect Ratio | 3:1 |
| Max File Size | 1 MB |
| File Formats | JPG, PNG, WEBP |
Starter Packs & Discovery
Starter Pack Name
| Character Limit | 50 characters |
|---|---|
| Notes | Curated lists of accounts and feeds for new users to follow |
Starter Pack Description
| Character Limit | 300 characters |
|---|
Feed Generator Name
| Character Limit | 24 characters |
|---|---|
| Notes | Custom algorithm feeds built on AT Protocol |