Overview
With IncaMail, messages up to 30 MB in size can be sent. However, whether a message can be successfully delivered depends not only on IncaMail but also on the size restrictions of the recipient's email server.
Important: Secure transport encryption can further increase the original size of a message. As a result, an email that complies with the allowed size before sending may still exceed the maximum acceptance limit at the recipient's end.
If an IncaMail message cannot be delivered due to a size restriction, the sender will receive a corresponding notification via email.
Recommendation
For important or time-sensitive shipments – especially in electronic legal communication (e.g., registered mail) – it is advisable to clarify the maximum allowable email size directly with the recipient in advance.
Size restrictions of common email providers
The following table shows the maximum allowable email size (including attachments) for various providers:
| Provider | Maximum Email Size (incl. attachments) |
|---|---|
| Bluewin | 15 MB |
| Gmail | 25 MB |
| GMX (free) | 20 MB |
| GMX ProMail | 50 MB |
| GMX TopMail | 100 MB |
| HIN Mail | 10 MB (external), 15 MB (internal) |
| iCloud Mail | 20 MB |
| Outlook.com | 20 MB |
| ProtonMail | 25 MB |
| Yahoo! Mail | 25 MB |
Note: These limits are set by the respective providers and can change at any time.
Electronic legal communication: Sending registered mail to authorities and courts
Special regulations apply to electronic legal communication in Switzerland. According to the Federal criteria catalog, recognized delivery platforms must support certain message sizes.
Legal requirements
According to the document “Requirements for platforms for secure delivery in legal procedures (Criteria catalog for delivery platforms)”, Article 6.4 “Sizes for electronic messages”:
The delivery platform must be able to process electronic messages with a payload size of 15 MB and a transport/delivery size of 25 MB.
This results in:
✅ Courts and authorities are required to accept electronic messages up to 25 MB in size.
Sending large files with Large File Transfer (LFT)
For larger files, IncaMail customers with domain connection (MGI) have access to Large File Transfer (LFT).
Advantages of Large File Transfer
- Sending files up to 1 GB
- Files are not sent directly as email attachments
- File size thus has only a minimal impact on the actual IncaMail message
- Reduces the risk of delivery issues due to size restrictions
For more information, see the article: Sending large files – Large File Transfer
Use of Large File Transfer in legal communication
Large File Transfer can also be used in official procedures, including:
- Administrative procedures (VeÜ-VwV, SR 172.021.2)
- Civil proceedings
- Criminal proceedings
- Debt enforcement and bankruptcy proceedings (VeÜ-ZSSV, SR 272.1)
Since IncaMail is a federally recognized secure delivery platform, the LFT function can also be used in these cases.
Summary
- IncaMail supports messages up to 30 MB.
- Actual deliverability depends on the recipient system’s limits.
- Transport encryption can further increase the message size.
- Authorities and courts must accept messages up to 25 MB.
- For larger files, Large File Transfer (up to 1 GB) is available.
- For important shipments, it is recommended to clarify the maximum allowable message size with the recipient beforehand.