Before you compose a message, check whether Reply or Add note is selected. If you are replying to a contact, also confirm that you have selected the correct messaging channel and that the channel supports the content you want to send.

Messaging capabilities and restrictions vary by channel. This article explains how to compose and send common types of content in Inbox. For exact messaging windows, supported formats, file limits, template requirements, and other restrictions, refer to the guide for the channel you are using.

Understand the message text box

The message text box appears at the bottom of an open conversation. It includes two tabs:

The tools available under Reply depend on the selected messaging channel. Channel messaging policies do not apply under Add note because internal notes are not sent through an external channel. General SleekFlow limits, such as file upload limits, may still apply.

Select a messaging channel

If a contact can be reached through more than one connected channel, a channel selector appears beside the Reply and Add note tabs. The channel you select determines where your reply is sent and which messaging tools are available.

To select a channel:

1. Open the conversation in Inbox.
2. Select Reply.
3. Click the channel selector beside the Reply and Add note tabs.
   
4. Select the channel you want to use.
5. Review the available messaging tools and any warnings displayed for the channel.

Before you send a reply, confirm that:

• You selected the correct customer channel.
• The channel is connected.
• The contact can receive messages through the channel.
• The channel supports the message type you want to send.
• The applicable messaging window is open.
• You are using a template if the channel requires one.

Changing the channel can change the tools and warnings shown in the message text box. The reply will appear in the conversation history for the channel through which it was sent.

Understand channel-specific messaging capabilities

Each messaging platform has its own capabilities and requirements. The channel you select can affect:

• Supported message types and file formats
• File size limits
• Messaging windows
• Template requirements
• Other platform-specific restrictions

SleekFlow may show only the tools supported by the selected channel. In other cases, the external platform may reject unsupported content when you try to send it. Platform capabilities can also change over time.

Content that is supported by one messaging channel might not be supported by another.

For the latest requirements, refer to the relevant channel guide:

• WhatsApp Business API: Supported message types
• WhatsApp Business API: Unsupported message types
• Facebook Messenger
• Instagram
• LINE Business
• Telegram
• WeChat
• Viber
• SMS

Reply to a contact

Use Reply to send customer-facing content through the selected messaging channel.

Send a text message

To send a text message:

1. Open a conversation in Inbox.
2. Select “Reply”.
3. Confirm the selected channel.
4. Enter your message in the message text box.
5. Press “Enter” or click “Send”.

Press “Shift + Enter” to start a new line without sending the message. Emojis form part of the message text and count toward the selected channel’s character limit.

Before sending, check that the message does not exceed the channel’s text limit and that the conversation is within the applicable messaging window. If free-form messages are unavailable, select an approved template instead.

After you send the message, it appears in the conversation history. Depending on the channel, its status can change from sending to sent, delivered, read, or failed. See Understanding message statuses and delivery issues for details.

Add emojis

Click the emoji  icon in the message toolbar, then select an emoji to insert it into your message. You can send an emoji with text or on its own, subject to the selected channel’s restrictions.

Emojis count toward the selected channel’s text limit.

Attach files and media

You can add files to a reply in any of the following ways:

• Click the attachment [screenshot] icon and select files from your device.
• Drag and drop files into the message text box.
• Paste files from your clipboard.

You can review or remove attachments before sending. Upload progress and errors appear in the message text box when applicable.

General upload limits are:

Common attachment types include images, videos, audio files, documents, and stickers in .WebP format. The selected channel may support fewer formats or impose a smaller size limit. Some platforms may also convert, compress, or reject files.

Refer to the relevant channel guide before sending an attachment if you are unsure whether it is supported.

Insert a Saved reply

Saved replies are reusable responses prepared by your workspace. They can include text and, where supported, attachments.

Before sending a Saved reply, review its content and confirm that its text and attachments are supported by the selected channel. Saved replies remain subject to the channel’s character limits, messaging windows, template requirements, and attachment restrictions.

To learn how to create, manage, and use Saved replies in Inbox, see Manage Saved replies in Inbox settings.

Send a voice message

If the selected channel supports voice messages, a microphone icon appears in the message toolbar.

To send a voice message:

1. Click the microphone  icon.
2. Record your message.
3. Review the recording. You can cancel it if you want to record again.
4. Send the voice message.

Voice messages can be up to 16 MB. This limit applies to recorded and uploaded audio messages. The channel may impose additional format or size restrictions.

If the microphone icon does not appear, the selected channel might not support voice messages. Refer to the relevant channel guide for its supported audio formats and limits.

Reply to a specific message

To quote an existing message in your reply:

1. Hover over the message.
2. Click the message action   icon beside it.
3. Select Reply.
4. Review the quoted message shown above the message text box.
5. Enter and send your response.

Quoted replies are not supported by every channel. Availability can also depend on the original message type. For other actions, such as copying and forwarding messages, see Working with conversations and messages in Inbox.

Schedule a message

You can schedule a customer reply to be sent later. Internal notes cannot be scheduled.

To schedule a reply:

1. Compose the message under Reply.
2. Confirm the selected channel.
3. Click the scheduling icon beside Send.
   
4. Select a preset time, or select Custom schedule to choose a future date and time.
5. Confirm the schedule.

Preset options include 5, 10, 15, 30, and 45 minutes, and 1 hour. A custom scheduled time must be at least 1 minute in the future.

The scheduled message appears in the conversation with its scheduled send time. A banner above the message text box also indicates that the conversation contains a scheduled message.

To cancel a scheduled message:

1. Hover over the scheduled message.
2. Click the message action  icon.
3. Select Cancel schedule.
   
4. Confirm the cancellation.

Warning: Scheduling a message does not guarantee that the channel will allow it when the scheduled time arrives. The message can fail if the messaging window has closed, a template has become required, the channel is disconnected, or the content is no longer valid for the channel.

Send product or payment content

If your workspace has the required commerce features and permissions, additional options may appear in the message toolbar. Depending on your setup, you can:

• Use Product catalog to browse products, add items to a cart, and share product details.
• Use Payment links to create and send a payment link in the conversation.

These options appear only when the relevant integrations, such as Shopify, a custom catalog, Stripe, or SleekPay, are configured. Availability also depends on the selected channel and your workspace configuration.

To learn more about sending payment links through Shopify, see Shopify integration: Payment.

Leave an internal note

Use Add note to share workspace-only information in a conversation. Contacts cannot see internal notes or teammate mentions.

Internal notes are useful when you need to record context, hand off a conversation, document follow-up actions, or ask a teammate for help.

Add a text note

To add an internal note:

1. Select Add note.
   
2. Enter your note in the message text box.
3. Confirm that Add note is still selected.
4. Press Enter to add the note.

Press Shift + Enter to start a new line without adding the note.

Mention a teammate

To mention a teammate in an internal note:

1. Enter @ followed by the teammate’s name.
   
2. Select the teammate from the list.
3. Finish writing your note.
4. Add the note.

The mentioned teammate receives a notification and can find the conversation under Mentions in the Inbox sidebar. Contacts cannot see the note or mention.

See Navigating and managing conversations in Inbox to learn more about Inbox views.

Add content to an internal note

You can also:

• Attach files by clicking the attachment icon, dragging and dropping files, or pasting from your clipboard.
• Insert a Saved reply by entering / at the start of the message text box and selecting a reply.
• Add emojis from the emoji picker.

External channel restrictions do not apply because internal notes are not sent to the contact. SleekFlow’s general upload limits still apply to attachments.

Use AI-assisted messaging tools

If AI features are enabled for your workspace, AI-assisted tools may appear in the message text box. Available tools can include:

• AI Smart Reply, which suggests a reply based on the conversation context.
• AI Writing Assistant, which can refine, shorten, translate, or change the tone of text you have written.
• AI Smart Summary, which summarizes a conversation for internal notes or handovers.

Review AI-generated content before sending or adding it. AI-generated replies follow the same messaging windows, template requirements, character limits, and format restrictions as manually written content.

Refer to the dedicated SleekFlow AI guides for setup and detailed instructions.

Resolve unsupported or failed messages

A message may fail to send if:

• The messaging window has closed.
• The channel requires a template.
• The message or attachment type is unsupported.
• The attachment is too large.
• The text exceeds the channel’s limit.
• The channel is disconnected.
• The contact cannot be reached through the selected channel.
• A required feature or integration is unavailable.
• The external platform rejects the content.

To resolve the issue:

1. Review the warning or failed-message information.
2. Confirm the selected channel.
3. Check the channel’s messaging window.
4. Replace unsupported content or reduce the file size.
5. Select an approved template if required.
6. Confirm that the channel is connected.
7. Review the channel-specific guide for exact requirements.
8. Retry the message after correcting the underlying issue.

For more help, see Understanding message statuses and delivery issues and the connection or troubleshooting guide for the selected channel.