SMS, MMS, and Bulk SMS FAQs
SMS, MMS, and Bulk SMS FAQs
Quick answers to the most common messaging questions.
General SMS
Q: Why didn't my SMS get delivered? Common reasons: the recipient's number is invalid, they've opted out (STOP), your number isn't 10DLC registered (US), or carrier filtering blocked the message. See SMS Delivery Troubleshooting for a full checklist.
Q: Can I send SMS internationally? Yes. JustCall supports SMS to 70+ countries. Rates vary by destination. Check your rate card under Settings → Billing.
Q: What's the difference between SMS and MMS? SMS is text-only (up to 160 characters per segment). MMS supports images, video, and documents (up to 5 MB). See SMS/MMS Overview.
Q: Do emojis affect my message cost? Yes. Emojis switch encoding from GSM-7 (160 chars/segment) to Unicode (70 chars/segment), which can increase segment count and cost. See SMS Segments Explained.
MMS
Q: Which countries support MMS? MMS is primarily available for US and Canadian numbers. International MMS support varies by carrier and country.
Q: What file types can I send via MMS? JPG, PNG, GIF, MP4, 3GP, PDF, and VCF. Maximum file size is 5 MB.
Q: How much does MMS cost? MMS is billed per message (not per segment) at a higher rate than SMS. See MMS Pricing.
Bulk SMS
Q: How many messages can I send in a bulk campaign? There's no hard cap on campaign size, but throughput depends on your number type and 10DLC trust score. High-trust 10DLC numbers and toll-free numbers have the highest throughput.
Q: Can I schedule a bulk SMS campaign? Yes. When creating a campaign, select Schedule instead of Send Now and choose a date and time.
Q: Can I personalize bulk messages?
Yes. Use dynamic variables like {{contact_name}} in your message template. Variables are replaced with contact-specific data from your CSV or CRM import.
Q: How do I stop a campaign that's already sending? Go to Bulk SMS → Campaigns → find the active campaign → click Pause or Cancel.