SMS and Email Attachment Size Limits in Sparkforge

By Sparkforge Support Team ·Last reviewed May 3, 2026

MMS attachments should stay under 500KB to clear every carrier. Email attachments cap at 20MB inside Sparkforge before files auto-route to Media Library links. Video uploads get auto-generated thumbnails.

SMS and MMS limits

SMS itself only carries text. The moment you add an image, video, or audio file, Sparkforge converts the message to MMS. Supported MMS file types are JPEG, PNG, and GIF. MP3, MP4, and PDF may work depending on the carrier and device.

Carrier-specific MMS size caps

Keep MMS attachments under 500KB to clear every major carrier. Specific caps:

Carrier	Long Code	Toll-Free	Short Code
AT&T	1.0 MB	0.6 MB	0.6 MB
T-Mobile	1.5 MB	0.6 MB	1.0 MB
Verizon	1.0 MB	0.6 MB	1.2 MB

Number type support for MMS

Type	MMS support	Recommended max size
Long Code (10DLC)	Yes	500KB – 1MB
Short Code	Yes	Up to 5MB
Toll-Free	Yes (since Oct 2022)	Up to 5MB

Email attachment limits

The Sparkforge email composer accepts up to 20MB in attachments. Files above 20MB auto-upload to the Media Library and ship as clickable links inside the email.

Limits at major email providers

Provider	Max attachment size
Gmail	25 MB
Yahoo Mail	25 MB
Outlook.com	10 MB
Mailgun	25 MB

How to attach files in Conversations

Open the conversation and click the three-dot icon (•••) in the message composer.
Select Attach Files. Choose Upload from System or Choose from Media Library.
For files over 20MB on email or oversize MMS, Sparkforge auto-uploads to the Media Library and inserts a clickable link.

Video thumbnails

Video files uploaded through the Media Library get an auto-generated GIF thumbnail rendered inside the email. The thumbnail makes the message more visual and clickable without manual editing.

Paste from clipboard

Skip the menu by pasting. Copy a supported file or image, click inside the message composer, and press Ctrl + V on Windows or Cmd + V on Mac.

Frequently Asked Questions

What's the largest file I can attach to an email in Sparkforge?

The composer accepts up to 20MB inline. Files larger than 20MB auto-upload to the Media Library and arrive as clickable links inside the email.

What MMS file types are supported?

JPEG, PNG, and GIF are fully supported. MP3, MP4, and PDF may work depending on the carrier and recipient device.

Why should I keep MMS files under 500KB?

AT&T, T-Mobile, and Verizon each cap toll-free MMS at 0.6MB and apply tight limits on long codes. Staying under 500KB clears all three with margin.

Do video email attachments get thumbnails?

Yes. Videos uploaded through the Media Library get an auto-generated GIF thumbnail that renders inside the email.

Can I paste an image into the message composer?

Yes. Copy the file or image, click inside the composer, and press Ctrl + V on Windows or Cmd + V on Mac.