SMS
To send attachments via Twilio, your Twilio phone number must have MMS (Multimedia Messaging Service) capability. Twilio allows a maximum of 10 attachments per message, provided that the combined size of the message text and all attachments does not exceed 5 MB.
It's important to note that carriers also limit attachment sizes. On average, these limits range from 300 KB to 600 KB, but for tier 1 providers such as AT&T and Verizon, the limit can be as high as 3.5 MB.
Here are the attachment size limits imposed by some common US carriers:
The mentioned file sizes are typically transmitted to wireless carriers. However, considering variations in handsets, file types, and transcoding processes, it is advisable to limit attachments to a maximum of 500 KB to enhance the likelihood of successful delivery.
The supported image file types for attachments include JPEG, PNG, and GIF.
Please be aware that Toll-Free MMS numbers have a specific limitation regarding file size support. For these numbers, it is crucial to ensure that any attachments, including images, are no larger than 600 KB.
For further details, refer to the following resource: Twilio Programmable SMS Supported File Types and Size Limits for MMS Media Messages.
Email server providers impose maximum email size limits primarily for security purposes. Without such limitations, email servers would be vulnerable to disruptions caused by the influx of extensive emails, leading to impaired functionality.
Certain free email address providers also set restrictions on email sizes for commercial reasons. Free accounts typically have lower maximum email size limits, but users can increase this limit by upgrading to a paid version.
If you attempt to send an email that exceeds the maximum email size limit set by the recipient's email provider, your email will be rejected, and you will receive an error notification in your Conversations tab. Common error messages include:
- "Attachment size exceeds the allowable limit."
- "552: Message size exceeds the maximum permitted."
- "System Undeliverable, message size exceeds the outgoing message size limit."
- "The size of the message you are trying to send exceeds the global size limit of the server. The message was not sent; reduce the message size and try again."
Mailgun, for example, supports a maximum message size of 25MB.
Here are the attachment size limits for different Email Providers:
FAQs
Q: Is it possible to send mp4 files via SMS?
A: No, attaching mp4 files directly to SMS messages is not supported. Recording a video using our mobile app will generate a link that recipients can click to view the video.
Q: Can the maximum email size limits be bypassed?
A: In short, bypassing these maximum size limits is impossible. However, there is a workaround available. You can upload the files you want to attach to cloud storage servers such as Dropbox, Google Drive, or SkyDrive and then include the download link in your email.