Trello integration with Slack comes from Atlassian in two parts. The Trello app for Slack turns a Slack message into a Trello card and shows card previews in Slack. The Slack Power-Up, added to each board, posts alerts to a Slack channel when cards move or change. You can also post to Slack from Butler automations, or use Zapier. Where they stop: a message saved from Slack lands in your Trello Inbox for someone to sort, alerts are set up board by board, private boards don't preview, and nothing follows up when a card goes quiet. AI agents do that sorting and chasing.
What a Trello integration with Slack has to do
Requests come in through Slack. The work is tracked in Trello. In between, someone reads the message, makes the card, adds the owner and due date, and later tells the person who asked that it's done. When that someone is busy, the request sits in a thread and nobody owns it.
So a good connection does two things. It turns a Slack request into a Trello card with an owner and a date, without retyping. And it tells the right people in Slack when that card moves, is late, or needs them.
Four ways to connect Slack and Trello
The first three come from Atlassian. The app and the Power-Up work together.
The Trello app for Slack
- How it works
- Atlassian's app in the Slack Marketplace. You make a card with /trello create, or save a message with Save for later, the inbox tray emoji, or Create card from message. Linked boards and cards show a preview in Slack.
- Good for
- Teams that want to save requests from Slack as cards in a few clicks.
- Where it breaks
- Saved messages go to your Trello Inbox, where someone still sorts them onto a board. Only workspace-visible boards and cards preview; private boards don't. Atlassian warns that saving a message to a board can show it to people who couldn't see it in Slack. The AI fill-in needs Trello Standard or higher.
The Slack Power-Up
- How it works
- You add it to a board, open it from the board header, select Add Slack alert, and set the Slack channel and the card actions to send.
- Good for
- Teams that want a channel to hear about card moves, comments and due dates on a few boards.
- Where it breaks
- Alerts are set board by board. Atlassian's staff say only mentions in comments reach Slack, not mentions in a card description, and each person turns on their own mention alerts per board. In Atlassian's community, alerts to private channels stopped until the Trello app was invited again.
Butler automations
- How it works
- Trello's built-in automation can post a message to a Slack channel as part of a rule, button or command, once Slack is added under Connected Apps. Its Slack listing gives the example of a message when a card is added to a list.
- Good for
- Teams that want one message at one moment, like a card moving to Done.
- Where it breaks
- Butler has to be added to each channel it posts in. In Atlassian's community, a Slack post from a Butler button worked for the admin who made it and failed for the rest of the team.
A Zapier zap
- How it works
- Zapier can create a Trello card, comment or checklist item from a new Slack message, mention, reaction or saved message, with fields you map yourself.
- Good for
- Teams that want a set rule, like each message in a requests channel becoming a card on one list.
- Where it breaks
- It copies the message as is. It doesn't read the request to set the owner or due date, and it doesn't follow up when the card goes quiet.
Arkeo agents
- How it works
- Agents read requests posted in Slack, make the card on the right board with an owner and due date, post updates back in the thread when the card moves, and flag work that is late.
- Good for
- Teams where requests come in through Slack and the board has to show where the work really is.
- Where it breaks
- Anything your rules keep for a person, like a request with no clear owner, goes to the right lead in one message.
How to connect Trello and Slack
These follow Atlassian's guide for the Trello app for Slack. Open it for the screens.
- 1Add the Trello app to Slack
Find Trello in Slack under Apps, or ask your Slack admin to add it. Then type /trello login in any channel, select Link account, and select Allow twice.
- 2Link your Trello Workspace to Slack
In Trello, open the Workspace settings, select Add to Slack under Slack workspaces linking, select your Slack workspace, then Allow twice. You'll get a message from the Trello app when it's done.
- 3Invite Trello to each channel
Type /invite @Trello in each channel that should show card previews or get alerts, private channels too.
- 4Add Slack alerts to each board
On the board, add the Slack Power-Up, open it from the board header, select Add Slack alert, then the channel and the card actions to send. Each person adds their own mention alerts.
- 5
Test with one request
Save one Slack message as a card, move it on the board, and check the alert lands in the right channel.
What still has to be done by hand
The app and the Power-Up move messages and alerts. The work in the middle is turning a request into owned work and seeing it through.
Saved messages wait to be sorted. Atlassian's guide says a message you save from Slack shows up in your Trello Inbox. Someone still has to move it to the right board and list, give it an owner and set a due date.
Alerts are narrow and set up by hand. Each board needs its own Slack alert. Atlassian's team wrote in its community that only mentions in comments reach Slack, not mentions in a card description, and that each person has to turn on mention alerts on each board.
Alerts stop without much warning. In one Atlassian community thread, alerts to private channels stopped with a channel cannot be found warning, and others saw no longer authorized to post alerts. The fix was to invite the Trello app back or reset and set up the link again. In another, a Butler button posted to Slack for its admin and failed for the rest of the team.
And nothing chases the work. When a card goes quiet or a due date passes, no one in the Slack thread hears about it unless someone writes back by hand.
The agents that do it
Each agent does one job from start to finish, in your own Slack and Trello. Your team talks to them in Slack.
Ask once in Slack. Someone owns it.
- Takes requests posted in your Slack channelas they come
- Turns each one into a task with an ownerright away
- Follows up until it's doneevery day
Late work gets caught before the client asks.
- Checks open cards and due datesevery morning
- Sends deadline notices to clients and staffahead of each date
- Flags late work to the ownerright away
Know where each client stands without opening Trello.
- Counts cards by list, owner and due dateevery Monday
- Finds work that is late or not movingper card
- Sends the report to the ownersMonday morning
Questions
Is my customers' information safe?
Yes. Agents work in your own Slack and Trello and see only what their job needs. Customer details never go into public AI. Agents connect to AI through business-grade connections audited under SOC 2.
Is the Trello integration with Slack free?
You need a Trello account to use the Trello app for Slack. Its Slack Marketplace listing says the AI fill-in for cards needs Trello Standard or higher.
Why did my Trello alerts stop posting to Slack?
In Atlassian's community, the usual fix is to invite the Trello app back to the channel with /invite @Trello, mostly for private channels. If that doesn't work, Atlassian's guide says to revoke the Trello Slack App in your Trello account settings, then log out and back in with /trello logout and /trello login.
Can I get a Slack message only when I'm tagged on a Trello card?
Yes. Open the board, select Slack in the header, and add mention notifications. Atlassian's team says only mentions in comments are sent, not mentions in a card description.
What does it cost?
You get the price on the call, along with the hours it saves your team.
Sources
- support.atlassian.com: the trello app for slack
- slack.com: A074YH40Z trello
- slack.com: AUJUMB00N butler by trello
- community.atlassian.com: slack powerup stopped working no more slack alerts are posted from tre
- community.atlassian.com
- community.atlassian.com: trello butler action is not posting to slack for everyone only the adm
- zapier.com: trello