SMS and MMS Messaging in JustCall: What You Can Send
SMS and MMS Messaging in JustCall: What You Can Send
JustCall lets you send text messages (SMS) and media messages (MMS) from your business phone numbers. Both message types land in your customer's native messaging app — no downloads, no apps, no friction.
Available on: All plans (MMS on Team plan and above)
SMS vs MMS: When to Use Each
| SMS | MMS | |
|---|---|---|
| Content | Text only | Text + images, videos, PDFs, vCards, GIFs |
| Character limit | 160 characters per segment (up to 10 segments) | 1,600 characters + up to 5 MB media |
| Best for | Quick replies, confirmations, reminders, links | Product photos, documents, marketing visuals |
| Cost | 1 message credit per segment | 3 message credits per message |
| Delivery | All carriers, all countries with SMS support | US and Canada only |
Tip: If your message is under 160 characters and text-only, send it as SMS. If you need to include an image or your text exceeds 160 characters and you want it delivered as a single message, use MMS.
SMS Character Limits and Segments
A single SMS segment is 160 characters using standard GSM-7 encoding. If your message exceeds 160 characters, JustCall automatically splits it into multiple segments.
| Encoding | Characters per segment | When it applies |
|---|---|---|
| GSM-7 | 160 (first segment), 153 (subsequent) | Standard Latin letters, numbers, common punctuation |
| Unicode (UCS-2) | 70 (first segment), 67 (subsequent) | Emojis, non-Latin scripts (Chinese, Arabic, Hindi, etc.) |
Why subsequent segments are shorter: Multi-part messages include a header that tells the recipient's phone how to reassemble the segments in order. This header uses 7 characters (GSM-7) or 3 characters (Unicode) per segment.
Characters that trigger Unicode encoding
A single emoji or non-Latin character switches the entire message to Unicode, cutting your per-segment limit from 160 to 70. Common triggers:
- Emojis (including simple ones like ✓ or ★)
- Accented characters beyond GSM-7 (e.g., certain diacritics)
- Chinese, Japanese, Korean, Arabic, Hindi, Thai characters
Tip: JustCall's compose area shows a live character count and segment estimate. Watch it as you type to avoid unexpected multi-segment charges.
Sending MMS Messages
MMS lets you attach media files to your messages. Supported file types:
| Media type | Supported formats | Max size |
|---|---|---|
| Images | JPEG, PNG, GIF | 5 MB |
| Video | MP4, 3GP | 5 MB |
| Audio | MP3, WAV, AMR | 5 MB |
| Documents | PDF, vCard (.vcf) | 5 MB |
How to send an MMS
- Open a conversation in the SMS Inbox.
- Click the attachment icon (paperclip) in the compose area.
- Select your file. JustCall validates the format and size.
- Add optional text in the compose field.
- Click Send.
Limitations:
- MMS is available for US and Canadian numbers only.
- Toll-free numbers support MMS but some carriers may render media as a link.
- International numbers are SMS-only.
Delivery Status Tracking
JustCall tracks delivery status for every message you send:
| Status | What it means |
|---|---|
| Sent | Message accepted by the carrier network |
| Delivered | Message confirmed delivered to the recipient's device |
| Failed | Carrier rejected the message (invalid number, blocked, etc.) |
| Undelivered | Carrier accepted but could not deliver (phone off, full inbox, etc.) |
View delivery status in the conversation thread or in your SMS Logs under the Analytics section.
Opt-Out Handling
JustCall automatically processes standard opt-out keywords. When a contact replies with STOP, UNSUBSCRIBE, CANCEL, END, or QUIT, JustCall:
- Sends a confirmation message: "You have been unsubscribed. Reply START to resubscribe."
- Marks the contact as opted out.
- Blocks all future outbound messages to that number from your account.
If the contact replies START or UNSTOP, JustCall automatically re-subscribes them.
You cannot override opt-out status manually. This is a carrier-level compliance requirement.