What types of limits apply to MMS Messages?
There are 2 types of limits that apply to all MMS messages:
Bandwidth’s File Size Limit - this is the maximum size file that Bandwidth will accept as an attachment for MMS messages, either as external media or as stored media.
Downstream Message Size Limit - downstream providers and carriers enforce a limit on the size of the payload entire MMS messages (which includes headers, text and media) on their network.
These limits are described in more detail below.
What are Bandwidth’s file size limits for MMS?
Bandwidth’s file size limits are the maximum file size that Bandwidth will accept. This size depends on the way that customers send their MMS traffic to Bandwidth.
Important: These sizes are the maximum size that Bandwidth’s platform will support. However, downstream providers enforce additional limits, and variations in handsets, file types, or transcoding can affect the ultimate deliverable of messages. For this reason, we recommend limiting messages to:
Maximum of 1000 characters for text
Maximum of 500 KB total combined size for all attachments.
For API Customers
There are 2 types of media upload available to customers: external media and stored media. Both upload types have a maximum file size of 3.5 MB.
Method | Description | Size limit | Attachment Limit |
External Media | The customer provides a URL from which Bandwidth will fetch media. | 3.5 MB per file | Maximum of 10 attachments |
Stored Media | The customer uploads their content to the Bandwidth Application Platform media server. | 3.5 MB per file | Maximum of 10 attachments |
For MM4 Customers
For MM4 Customers, Bandwidth’s limit applies to the entire message payload.
Method | Description | Size Limit |
MMS Payload | The customer provides media in the MMS Payload. The limit applies to the entire message payload (see “How is Message Payload Size Calculated") | 5 MB total payload. |
What are the Downstream Size Limits
Downstream provider and carrier limits are based on the total message payload size, which includes headers, text and media, as well as additional overhead for encoding (see “How is Message Payload Size Calculated”). Limits are set on a per-channel basis for each destination carrier. Current downstream limits are described in the table below.
Notes:
Due to variations in handsets, file types, and transcoding, we recommend limiting the total message as follows to provide the best chance for delivery:
Maximum of 1000 characters for text
Maximum of 500 KB total combined size for all attachments.
Because these limits are often enforced downstream, customers may be able to send higher than the published limit in some cases.
Number of Attachments - both downstream providers and carriers may enforce a limit on the number of attachments they will accept.
Carrier | 10DLC | Short Code | Toll-Free |
AT&T | 1 MB | 1 MB | 525 KB |
T-Mobile | 3MB | 1 MB | 525 KB |
Verizon | 1.2 MB | 1 MB | 525 KB |
US Cellular | 500 KB | 500 KB | 525 KB |
How is Message Payload Size Calculated
The message payload includes all headers, text, and media files. Additionally, encoding will add approximately 1/3 (33% ) to the message size. The graphic below shows how the message payload is calculated.
The message_size field in MDRs, when available, will reflect this payload size. Note that for some failure scenarios, message_size is not available at this time.
Note:
For BAA customers, the added encryption may add up to an additional 15% to the encoded size
What happens if my MMS message is too large?
For Toll-Free and Short Code MMS, if your overall message payload size is too large for the target carrier, either Bandwidth or a downstream provider may reject the message as being oversized, and customers will receive a DLR with the appropriate error code:
Bandwidth rejects: (4)411
Downstream carrier rejects: (4)711
For 10DLC MMS, images and video may be resized to meet the acceptable carrier limits (see “Will Bandwidth resize or transcode images and video for MMS Messaging?”).
Can I programmatically determine the destination carrier’s maximum MMS file size?
No, not at this time.
Will Bandwidth resize or transcode images and video for MMS Messaging?
For 10DLC MMS messages with a single attachment, images and video will be resized to meet acceptable carrier limits. Media for messages that have multiple attachments will not be resized, and may be rejected if the total payload is over the destination carrier limit. Bandwidth recommends that you only send messages that do not exceed a payload of 500KB to ensure the best chance of delivery.
For Toll-Free and Short Code, media transcoding/resizing is not provided, and either Bandwidth or a downstream provider will reject messages that are over the destination carrier’s allowed limits.