Make calls in Slack

Sometimes it helps to talk things out. With Slack Calls, you can make a voice or video call with any member of your Slack team. 📞✨

 

The basics 

Before you dive in, get familiar with Slack's call features and availability. 

Features 

Voice call   Talk with your teammates in Slack.
Video call   Talk or video conference in Slack.
Share your screen Present your screen to the other call participants.* 

 *Available only to paid teams.

Availability

  Mac Windows Linux iOS Android
Voice calls   ✓  ✓  ✓  ✓  ✓
Video calls   ✓      
Screen sharing   ✓  ✓      

 

Supported browsers: Using Google Chrome, you can make voice and video calls; you’re also able to view a teammate's screen, but you’re unable to share your own. At this time, Firefox is not supported.

 

Start a call

Desktop

iOS 

Android

There are two ways to start a call: from a direct message or a channel

From a direct message

Both free and paid teams can start a call from a direct message. Here's how:

  1. Open a direct message.
  2. Click the  phone icon at the top of your screen.
  3. In one-to-one and group DMs, your call will start right away, and the team member(s) you're calling will receive a pop-up notification.
  4. If you use Slack on your Mac or Windows desktop, you can click the  camera icon to turn it into a video call. 

Note: If the team member you're calling is set to away or if they're in Do Not Disturb mode, they'll get a missed call notification.


From a channel

If you're on a paid team, you can also start calls in channels. To do so, follow the steps below.

  1. Open a channel and click the  phone icon at the top of your screen.
  2. In a channel, we'll first confirm you'd like to start a call. Name the call if you'd like, and click Start new call when you're ready. 
  3. Your call will post to the channel and any member — up to 15 total — will be able to join by clicking Join this call in the channel.
  4. If you use Slack on your Mac or Windows desktop, you can click the   camera icon in the call window to turn it into a video call.
  1. Tap the channel or direct message name to expand the Channel or Conversation Settings.
  2. Tap Start a call.
  1. Tap the channel or direct message name to expand the Channel or Conversation Info pane.
  2. Tap Start a call from the Actions Menu.

Tip: Want a shortcut for making calls? We've got a slash command for that! Use /call in a DM or channel to start a call.

 

Share and invite others to a call

If you're on a paid team, you can share calls and invite others to join them.

Desktop

iOS

Android

To invite a specific team member to join your current call, follow these steps:

  1. Click the  plus icon in the upper-right corner of the call window.
  2. Start typing a name to filter the list.
  3. Select a team member to invite.

If you'd like to share a call in other channels, here's how:
  1. Click the  plus icon in the upper-right corner of the call window.
  2. Click Share this call.
    share-call-in-channel.png
  3. Select a channel from the drop-down menu and click Share. Or, to get a link for the call you can manually share, click Copy link.

 

  1. Tap Invite.
  2. Tap the names of the people you'd like to invite to the call
  3. Tap Invite again
  1. Tap Invite.
  2. Tap the names of the people you'd like to invite to the call
  3. Tap Invite again

 

Join a call

Answer a direct message call

Desktop

iOS

Android

When another team member calls you in a one-to-one or group DM, you'll see a pop-up call notification. Click the green  phone icon to answer the call.

Tap the green  phone icon to answer the call.
Tap Answer from the pop-up notification or on the call message in the direct message.

Join a channel call

Desktop

iOS

Android

Click Join this call from the in-channel invitation. A call window will open where you can see who else is on the call, and who is speaking.call-full-layout.png

 

Tap Join this call from the channel where the call is taking place.
Tap Answer from the channel where the call is taking place.

 

Share your screen

Meetings are meant for sharing ideas. If you use the Slack on Mac or Windows desktop apps, during a call, any participant can present their screen by clicking the  Share your screen icon.

Full_Layout_-_screensharing__1_.png

Note: Screen sharing isn't available for Slack's mobile apps at this time.

Helpful tips

Take turns

Only one person can share their screen at a time during a call. When you're done presenting, unshare your screen to allow the next person to take the reins.

 

Active speaker 

Whoever is sharing their screen becomes the active speaker on the call by default. This means that your other teammates on the call will only see your screen, even when others are speaking.

 

Google Chrome

If you're using Google Chrome, you can view your teammates shared screen, but you're unable to initiate a screen share on your end.

 

Call actions

Desktop

iOS

Android

You'll find built-in controls in your call window:

Action Icon
Add a team member to a call or share a call in a channel  
Mute or unmute your microphone    
Enable or disable a video call  
Enable or disable screen share  
Call settings (call name + voice and video settings)  
Send an emoji reaction   
Exit a call   

 

You can also use keyboard shortcuts:

Action Key
Toggle mute on and off M
Toggle video on and off V
Show the invite list + or A
View Channel sharing options S
View and select and emoji reaction E then 1 - 9

Start a call

Tap the channel or direct message name to expand the Channel or Conversation Info pane. Next, tap Start a call from the Actions Menu.


End a call

Press the red End button.


Answer a call

Tap Answer from the pop-up notification or on the call message in the channel or direct message where the call is taking place.


Decline a call

Press Dismiss on the pop-up notification. 

Start a call

Tap the channel or direct message name to expand the Channel or Conversation Settings, and choose Start a call.


End a call

Press the red  End button.


Answer a call

Tap the green  phone icon to accept a call in a direct message or Join this call from the channel where the call is taking place.


Decline a call

Press Decline to dismiss an incoming call.

 

Troubleshooting

Connection errors

Audio errors

Video errors

Tip: Firewalls are the most common reason for call connection issues. Below are tips for resolving these errors.

 

Call connection error

If Slack is having trouble establishing a call connection, check that your network is set to allow outbound UDP connections to port 22466 and whitelist *.slack-core.com, or ask your IT admin to do so. Our servers are reassigned dynamically within our hosting environment Amazon Web Services (AWS), so we don't have a list of static IP addresses to share.

Below is a list of bandwidth requirements for optimal performance: 

Type of call  Download speed  Upload speed 
 Voice call  200 kbps  100 kbps
 Video call* (2 participants)  600 kbps  600 kbps
 Video call* (3 participants)  2 Mbps  600 kbps
 Video call* (5+ participants)  4 Mbps  600 kbps

*Requirements are the same for screen sharing.

 

Server connection error

If you're trying to make a call and Slack is having trouble connecting to the server, try opening slack.com in a browser.

  • If slack.com does not load, please check that your network is set to allow outbound TCP connections to port 443.
  • If slack.com does successfully load and you still see a server error, write to us and we'll investigate to see what the connection trouble may be.

If you're running into issues with the audio, ask all members on the call to try the following: 

  • If you're using Slack on a desktop, check the audio settings by clicking the   gear icon in the call window and make sure the correct input and output device is selected.
  • Check the device’s system preferences to make sure the audio is not muted and that the correct input and output device is selected.
  • Restart Slack, then try to make your call again.
  • If you're using Slack in Google Chrome, quit Chrome, relaunch your browser, and then reopen Slack.

WebGL unavailable

Slack Calls relies on a technology called WebGL to for video and screen sharing to work. There are a number of reasons why WebGL may be unavailable:

  • Your computer’s graphics card drivers are out of date or they’re simply not working. These drivers control how graphic components work with the rest of your computer.
  • Your computer’s graphics card may not be working or the operating system isn’t switching to the correct graphics card.
  • Your computer’s graphics processing unit (GPU) is blacklisted for performance reasons. For example, some 2011 MacBooks with an Intel 3000 HD graphics card may be blacklisted.
  • If you have USB to DVI adapter plugged into your monitor, it can sometimes fake a graphics driver, causing your actual graphics driver not to work.
  • If you’re using multiple monitors during a video call, this could cause repeated graphics process crashes.

Tip: Are you experiencing an issue with video or screen sharing? Try restarting Slack to see if that helps, but let us know if you’re still having trouble.

 

Video connection error

If the video on your call is out of sync, freezes, or disconnects, give the following tips a try:

  • Make sure you have a strong network connection.
  • To check that your bandwidth meets the video call requirements, run a speed test.

 

Your video fails to display

If your video doesn't display during a call, try these tips:

  • If you're using an external camera, make sure to plug it in before you start a call. Your video will fail to display if the camera is plugged in during a call.
  • If you've plugged in your camera before starting a call and you're still having trouble, try the following:
    1. Click the   gear icon in the call window to check your Video settings.
    2. Make sure the correct camera is selected.
  • If you continue to have trouble, try manually selecting a different camera, then select your desired camera again.

 

High CPU

If you notice your computer runs more slowly when you're on a video call, this may be due to high CPU (central processing usage). For calls with many participants, we recommend turning video off when it’s not needed and re-enabling video when it is.

 

Security

Slack's voice and video calls use Opus and VP8 to encode audio and video respectively, and all traffic is encrypted in transit to protect the integrity and confidentiality of a call. Slack uses DTLS for the media stream and HTTPS for signaling with the media server. 

Some metadata from a call is stored in Slack, including the following: the name of a call, location a call was started (channel, group, or direct message), who started and participated in a call, and performance metrics (latency, jitter, etc.), which helps with debugging, support, and improving the quality of the service. The time a call starts, ends, and when members join or leave a call is also captured.

Note: Logs or copies of calls are not recorded or stored in Slack. Slack's voice and video calls fall under the same security program as the rest of Slack. For more information, visit our Security policy.

Who can use this feature?
  • By default, all members and Guests can use this feature. 
  • Available to teams on free and paid plans.

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