# Email specifications
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If you are sending **promotional emails** using the **web interface**, use the built-in **email editor** to create, optimize, manage, and track your messages.

Check the following email specifications:

| Specification           | Value |
|-------------------------|-------|
| **Max total email size** | 25 MB |
| **Max attachment size** | The maximum supported attachment size is **25 MB**. The total request size can be **up to 26 MB**, where the remaining 1 MB is reserved for recipients and other request data, including the message content.<br/><br/>Unsupported types: ade, adp, apk, appx, appxbundle, bat, cab, chm, cmd, com, cpl, dll, dmg, ex, ex_, exe, hta, ins, isp, iso, jar, js, jse, lib, lnk, mde, msc, msi, msix, msixbundle, msp, mst, nsh, pif, ps1, scr, sct, shb, sys, vb, vbe, vbs, vxd, wsc, wsf, wsh |
| **Subject line**        | Max 200 characters (emojis count as 2 characters) |
| **Preheader**           | Max 75 characters (emojis count as 2 characters) |
| **HTML size limit**     | 10 MB |
| **Max attachments**     | 20 |
| **Content storage**     | **Early access**: Infobip offers a solution for extended email retention (up to 10 years) that stores full email content, including HTML, placeholders, and attachments. Pricing varies based on traffic volume, email size, retention period, and storage location (cloud or on-premise), and applies to all sending methods (web and API).<br/><br/>Two storage options are available:<br/><br/>- [Passive email storage (archives)](https://www.infobip.com/docs/email/email-storage-and-retrieval/passive-email-storage): Long-term retention (**from 1 to 10 years**), accessed occasionally (for example, disputes, compliance).<br/>- [Active email storage (logs/reports)](https://www.infobip.com/docs/email/email-storage-and-retrieval/active-email-storage): Short-term retention (**3 months** by default), accessed daily through logs and reports.<br/><br/>To learn more about this feature, contact [Support](mailto:support@infobip.com) or your dedicated account manager.|
| **Image handling**      | All images are externally linked (not embedded) |
| **Sensitive data masking**      | Protects confidential information by masking data in email content using configurable placeholder rules. Done by masking personal identifiers, contact details, physical addresses, and any dynamic placeholder value, with full options available under [placeholdersMasking](https://www.infobip.com/docs/api/channels/email/email-message-sending/send-email-messages-api).  |
| **PDF attachment encryption** | Secures confidential information by password-protecting and encrypting PDF attachments before delivery to prevent unauthorized access. Passwords are set during [API](https://www.infobip.com/docs/api/channels/email/email-message-sending/send-email-messages-api) upload, required to open the file, and never exposed in the email or attachment metadata. |
| **Data retention**      | See the [data retention policy](https://www.infobip.com/policies/data-retention-notice) for full data handling and retention rules. |

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