> For the complete documentation index, see [llms.txt](https://docs.messageflow.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.messageflow.com/rcs/first-steps/technical-specifications.md).

# Technical Specifications

This section outlines the key technical guidelines to consider when preparing materials for an RCS campaign.

Following these recommendations ensures that your assets display correctly across different devices.

### Dimensions and File Formats

| Component                  | Dimensions / Aspect Ratio                      | Supported Formats                                                                   |
| -------------------------- | ---------------------------------------------- | ----------------------------------------------------------------------------------- |
| Video (Standalone Message) | 16:9 or 9:16                                   | h263, m4v, mp4, mpeg, mpeg4, webm                                                   |
| Rich Card (Media)          | Suggested: 770 × 335 px (for horizontal media) | <p>Images: GIF, JPG, JPEG, PNG <br><br>Video: h263, m4v, mp4, mpeg, mpeg4, webm</p> |
| Carousel (Media)           | Suggested: 605 × 452 px (4:3 aspect ratio)     | Images: JPG, JPEG, PNG                                                              |
| File (Audio / PDF)         | Not applicable                                 | <p>Audio: MP3, WAV <br><br>Document: PDF</p>                                        |

### Character Limits and File Sizes

#### Character Limits

| **Component**                      | **Maximum Character Count (UTF-8)** |
| ---------------------------------- | ----------------------------------- |
| RCS Basic / Lite                   | 160 characters                      |
| Single Text (description)          | 1,000 characters                    |
| Rich Card / Carousel (title)       | 100 characters (24 recommended)     |
| Rich Card / Carousel (description) | 1,000 characters (77 recommended)   |
| Suggestions (button text)          | 25 characters                       |

#### File Sizes

| **Component**               | **Maximum / Recommended Size** |
| --------------------------- | ------------------------------ |
| Video (Standalone Message)  | Maximum: 20 MB                 |
| Audio File                  | Maximum: 20 MB                 |
| Rich Card (Image)           | Recommended max: 4 MB          |
| Rich Card (Video)           | Maximum: 5 MB                  |
| Document (PDF)              | Recommended max: 5 MB          |
| Graphics in Cards (General) | Recommended size: 40–100 kB    |

### Safe Area (Padding)

Due to variations in device displays and system overlays, key graphic elements (such as logos, text, or main product visuals) should be placed within the defined safe area.

This ensures they remain fully visible across all screen types.

**For Rich Card (single card):**

* Top and bottom margins: 20 px
* Left and right margins: 180 px

**For Card Carousel:**

* Top and bottom margins: 121 px
* Left and right margins: 75 px