How Messaging Works (SMS/MMS)
Phound numbers have individual VOICE, SMS, and MMS capability badges. A number may have some or all of these capabilities. Check the badges for the number you intend to use before calling or sending an individual text or picture message.
Phound does not support group MMS chats. An MMS badge identifies a number's multimedia messaging capability, not support for a shared carrier group conversation. In-app groups between Phound users and Wave broadcasts are different from carrier SMS/MMS groups.
This guide covers individual carrier messages, media attachments, delivery receipts, and the group messaging distinction. See Number Features for where to review a number's badges.
SMS vs. MMS: What Is the Difference?
For an individual carrier conversation, use a number with the capability required for the message:
SMS (Short Message Service)
SMS is the standard text message format that has been around for decades. SMS messages are text-only and have a limit of 160 characters per message segment. If you type a longer message, it is automatically split into multiple segments that are reassembled on the recipient's device. Most of the time, this splitting happens seamlessly and the recipient sees one continuous message.
MMS (Multimedia Messaging Service)
MMS messages can contain media, photos, videos, audio clips, and animated GIFs, in addition to text. MMS messages can also be longer than SMS messages, supporting up to approximately 1,600 characters of text along with media attachments.
Phound automatically determines which message type to use based on what you send:
- Text only (160 characters or fewer): Sent as SMS
- Text only (more than 160 characters): Sent as multi-segment SMS
- Text with an image, video, or other attachment: Sent as MMS
Tip: SMS/MMS formatting for an individual conversation does not enable group MMS. Adding recipients is not a way to create a supported carrier group chat.
How Messages Are Delivered
When you send an individual carrier text through Phound, the message follows this path:
- You compose and send the message from the Phound app.
- The message is transmitted over your data connection (Wi-Fi or cellular data) to Phound's messaging servers.
- Phound's servers route the message to the recipient's carrier using standard SMS/MMS protocols.
- The recipient's carrier delivers the message to their phone.
- The recipient sees the message appear as a normal text from your Phound number.
The recipient does not need Phound installed. Your message arrives as a regular text on their device, and they can reply just like they would to any other text message. When they reply, the response is routed back through Phound and appears in your persona's message inbox.
Delivery Speed
Most Phound messages are delivered within seconds, comparable to standard carrier messaging. However, delivery times can vary based on:
- The recipient's carrier: Some carriers process messages faster than others.
- Network conditions: High traffic periods may add slight delays.
- Media file size: Larger MMS attachments may take a few extra seconds to deliver.
- International messages: Messages sent to international numbers may experience slightly longer delivery times.
Character Limits and Message Segments
Understanding character limits helps you predict how your messages will be sent and billed:
| Message Type | Character Limit | Notes |
|---|---|---|
| Single SMS | 160 characters | Standard text characters (GSM-7 encoding) |
| Multi-segment SMS | No hard limit | Split into 153-character segments |
| SMS with special characters | 70 characters per segment | Unicode encoding (emojis, non-Latin scripts) |
| MMS text | ~1,600 characters | Text accompanying media in an individual carrier conversation |
A Note on Emojis and Special Characters
Emojis and characters from non-Latin alphabets (such as Chinese, Arabic, or Cyrillic) use Unicode encoding, which reduces the per-segment limit from 160 characters to 70 characters. This means a message with even one emoji could be split into more segments than the same message without it.
This does not change the recipient's experience, but it can affect usage. Review the current messaging allowance and segment rules shown for your account.
Warning: Very long SMS messages that span many segments may be delivered out of order on some carrier networks, especially with older phone models. If you regularly send lengthy texts, consider keeping them under 300 characters or using MMS, which handles longer content as a single message.
Group Messaging
Phound does not support group MMS chats. Do not use multiple external phone numbers to create a shared carrier group conversation in Phound.
In-App Groups and Wave Broadcasts
- Individual SMS/MMS is a carrier conversation with one recipient, using a number with the required capability.
- In-app group chats are between Phound users. They are not carrier group MMS chats. This guide does not establish an in-app group participant limit.
- Phound Wave sends broadcasts and campaigns to an audience. A Wave Blast is not a shared carrier group chat. See What Is Phound Wave?.
Incoming External Group Messages
The exact handling of incoming external carrier group messages, including whether they appear in an individual conversation and where a reply goes, has not been confirmed for this guide. Do not assume a message will be received or that a reply will reach the whole group. Contact Support about a specific case instead of relying on a group conversation for delivery.
Picture and Video Messages
Use a number with an MMS badge for picture and video messages to an individual carrier recipient. Phound supports common media formats including JPEG, PNG, GIF, and MP4.
Media Size Limits
MMS has inherent file size limitations set by carrier networks. Phound automatically compresses media to meet these requirements:
- Images: Compressed to fit within carrier limits (typically under 1 MB). Most photos are optimized without noticeable quality loss.
- Videos: Compressed to approximately 3.5 MB or less. Longer or high-resolution videos will be compressed more aggressively, which may reduce quality.
- GIFs: Animated GIFs are supported but may be compressed or resized to fit carrier size limits.
Tip: For the best quality when sharing videos, consider sending shorter clips. Carrier MMS size limits apply universally and are not specific to Phound. If you need to share a full-resolution video, a file sharing service will deliver better results than MMS.
Delivery Receipts and Read Indicators
Phound provides delivery receipts to let you know your message has been sent successfully:
- Sent: Your message has left Phound's servers and has been handed off to the recipient's carrier.
- Delivered: The recipient's carrier has confirmed receipt of the message. This appears as a small "Delivered" indicator beneath your message.
What Phound Does Not Support
Standard SMS/MMS does not support read receipts or typing indicators. These are features of proprietary messaging systems like iMessage and RCS. When you text someone through Phound, you will know the message was delivered, but you will not be able to see when (or if) it was read.
Message Storage and History
All of your Phound messages are stored within the app and organized by persona. Each persona has its own inbox with separate conversation threads, so messages from different numbers never mix together.
How Long Are Messages Stored?
Phound stores your message history on our servers as long as your account is active. You can scroll back through past conversations at any time. Messages are also cached locally on your device for faster access.
Deleting Messages
You can delete individual messages or entire conversation threads from within the app. Deleting a message removes it from your Phound account. Keep in mind that deleting a message on your end does not remove it from the recipient's phone, once a text is delivered, you cannot unsend it.
For a hands-on walkthrough of composing and sending messages, continue to our guide on how to send and receive text messages.
Tip: If you are using Phound for business communication, consider periodically reviewing and archiving important message threads. While Phound retains your history, keeping your inbox organized makes it easier to find specific conversations when you need them.
Still Need Help?
If you have questions about messaging in Phound or are experiencing delivery issues, here are your options:
- Search the Knowledge Base: Find answers to common messaging questions using the search bar at the top of any page.
- Contact Support: Get help from our support team via Settings > Help & Support in the app.
- Check your data connection: Many messaging issues are related to a weak or unstable internet connection. Try switching between Wi-Fi and cellular data to see if delivery improves.
Text messaging with Phound works just like regular texting, because it is regular texting, just from a number that keeps your real one private.