How to Send Asana Milestone Updates to Slack with Zapier

zapier.com > Dashboard > Create Zap

Create a new Zap

Log in to zapier.com and click the orange 'Create Zap' button in the left sidebar. The Zap editor opens in a two-panel view: the left panel shows your steps, the right panel shows the configuration for the selected step. You'll build the Zap top-to-bottom — trigger first, then action. Give the Zap a clear name at the top, like 'Asana Milestone → Slack #project-updates', before you configure anything else.

1. 1Click 'Create Zap' in the left sidebar
2. 2Click the name field at the top and type a descriptive Zap name
3. 3Click '1. Trigger' in the left panel to begin trigger configuration

Zap Editor > Trigger > Search Apps > Asana

Select Asana as the trigger app

In the trigger search box, type 'Asana' and select it from the dropdown. Zapier will ask you to choose a trigger event — this is the most important decision in the Zap. For milestone completions, select 'Completed Task in Project'. For deadline proximity alerts, you'll need a separate Zap using a Schedule by Zapier trigger combined with an Asana search step — pick one approach now and finish the other later. Stick with 'Completed Task in Project' for this walkthrough.

1. 1Type 'Asana' in the trigger app search box
2. 2Click 'Asana' in the results
3. 3Click the 'Event' dropdown
4. 4Select 'Completed Task in Project'
5. 5Click 'Continue'

Zap Editor > Trigger > Connect Asana > OAuth popup

Connect your Asana account

Click 'Sign in to Asana' and a popup will open asking you to authorize Zapier. Log in with the Asana account that has access to the projects you want to monitor. Zapier requests read access to your Asana workspace. Once authorized, the popup closes and you return to the Zap editor with your Asana account listed. If your organization uses Asana SSO, you'll authenticate through your identity provider in this popup.

1. 1Click 'Sign in to Asana'
2. 2Enter your Asana credentials or use SSO in the popup
3. 3Click 'Allow' to grant Zapier access
4. 4Confirm your account name appears in the account selector
5. 5Click 'Continue'

Zap Editor > Trigger > Configure > Project dropdown

Select the Asana project to monitor

Zapier now asks you to configure the trigger. Open the 'Project' dropdown — it pulls a list of all projects visible to your connected Asana account. Select the specific project containing your milestone tasks. If you want to monitor multiple projects, you'll need one Zap per project. There is no multi-project trigger in Zapier's Asana integration. You can optionally filter by Section if your milestones are organized into a dedicated section like 'Milestones' or 'Phase Gates'.

1. 1Click the 'Project' dropdown
2. 2Type the project name to filter the list
3. 3Select your target project
4. 4Optionally select a Section to narrow the trigger to milestone tasks only
5. 5Click 'Continue'

Zap Editor > Trigger > Test Trigger

Test the trigger and load sample data

Click 'Test trigger' — Zapier polls Asana for recently completed tasks in the selected project and returns up to 3 sample records. You need at least one completed task in the project for the test to return data. If the project is brand new, complete a test task in Asana first, then return and run the test. Review the sample data to confirm the fields you'll need are present: task name, completion date, assignee, due date, project name, and the direct link to the task.

1. 1Click 'Test trigger'
2. 2Wait 5-10 seconds for Zapier to poll Asana
3. 3Click the returned record to expand all fields
4. 4Confirm 'Name', 'Completed At', 'Assignee Name', and 'Permalink URL' are present

Zap Editor > + > Filter by Zapier

Add a Filter step to isolate milestone tasks

Click the '+' icon between the trigger and the next action to insert a Filter by Zapier step. This ensures only milestone tasks send a Slack message. Set the filter condition to: 'Name' contains 'Milestone' — or whatever naming convention your team uses for milestone tasks. If your team uses a custom field in Asana called 'Task Type', you can filter on that value instead. The Zap will stop and send nothing to Slack if the condition is not met.

1. 1Click the '+' between trigger and action
2. 2Select 'Filter by Zapier'
3. 3Set field to 'Name' (from Asana trigger data)
4. 4Set condition to '(Text) Contains'
5. 5Type your milestone identifier, e.g. 'Milestone' or 'Phase'
6. 6Click 'Continue'

Zap Editor > + > Slack > Send Channel Message

Add Slack as the action app

Click the '+' after the filter step and search for 'Slack'. Select 'Send Channel Message' as the action event. This posts a message to a public or private Slack channel. Do not select 'Send Direct Message' — this use case is about team-wide visibility, not individual pings. You'll configure the exact channel and message content in the next two steps.

1. 1Click the '+' to add an action
2. 2Type 'Slack' in the search box
3. 3Click 'Slack'
4. 4Select 'Send Channel Message' as the event
5. 5Click 'Continue'

Zap Editor > Action > Connect Slack > OAuth popup

Connect your Slack workspace

Click 'Sign in to Slack' and authorize Zapier to post messages on behalf of a Slack bot. The OAuth screen lists the permissions Zapier requests: posting to channels and optionally reading channel lists. Choose the correct workspace from the dropdown if you belong to multiple. After authorization, Zapier creates a bot called 'Zapier' in your Slack workspace — messages will appear to come from this bot unless you customize the bot name in the action configuration.

1. 1Click 'Sign in to Slack'
2. 2Select the correct workspace from the dropdown
3. 3Click 'Allow' to grant permissions
4. 4Confirm your workspace name appears under 'Connected Account'

Zap Editor > Action > Configure > Channel + Message Text

Configure the Slack message

Now map your Asana fields into the Slack message. Set the Channel field to your target channel — type '#' to search by name. In the Message Text field, build a clear status update using Asana data. Click into the Message Text box and use the purple data pill picker to insert dynamic fields. A well-structured message should include the milestone name, the project it belongs to, who completed it, when it was completed, and a direct link. See the field mapping section below for the exact fields to use.

1. 1Click the 'Channel' field and type the channel name or select from the list
2. 2Click into the 'Message Text' field
3. 3Type your message template, inserting Asana data pills where needed
4. 4Set 'Bot Name' to something recognizable like 'Asana Updates'
5. 5Optionally set 'Bot Icon' to an Asana logo emoji :asana:
6. 6Click 'Continue'

📬 New entry: {{1.name}}
Email: {{1.email}}
Details: {{1.description}}

Zap Editor > Insert Step > Formatter by Zapier > Date / Time > Format

Add a Formatter step to clean up the timestamp

Go back and insert a Formatter by Zapier step between the Filter and the Slack action. Choose 'Date / Time' as the transform type and 'Format' as the action. Map the 'Completed At' field from Asana as the input. Set the output format to 'MMMM D, YYYY [at] h:mm A' — this produces output like 'March 15, 2024 at 2:32 PM'. Then return to the Slack action and swap the raw timestamp data pill for the Formatter output. This one step makes the Slack message readable to non-technical teammates.

1. 1Click '+' between Filter and Slack action
2. 2Select 'Formatter by Zapier'
3. 3Choose 'Date / Time' then 'Format'
4. 4Set Input to the 'Completed At' data pill from Asana
5. 5Set 'To Format' to 'MMMM D, YYYY [at] h:mm A'
6. 6Click 'Continue', then update the Slack message to use the Formatter output

📬 New entry: {{1.name}}
Email: {{1.email}}
Details: {{1.description}}

This Code by Zapier step runs after the Formatter step and before the Slack action. It compares the task's due date against the completion date and appends a late indicator to the message if the milestone was finished after its due date. Paste this into a 'Run Python' Code by Zapier step and map 'input_data' fields to the Asana due date, completed date, task name, project name, assignee name, and permalink from earlier steps.

# Code by Zapier — Python
# Adds late/on-time indicator to Slack message before sending
# Map these in the input_data section of the Code step:

# Code by Zapier — Python
# Adds late/on-time indicator to Slack message before sending
# Map these in the input_data section of the Code step:
# due_date, completed_date, task_name, project_name, assignee_name, permalink

from datetime import datetime

# Parse dates from Asana (date fields arrive as 'YYYY-MM-DD' strings)
due_raw = input_data.get('due_date', '')
completed_raw = input_data.get('completed_date', '')
task_name = input_data.get('task_name', 'Unknown Task')
project_name = input_data.get('project_name', 'Unknown Project')
assignee = input_data.get('assignee_name', 'Unassigned')
permalink = input_data.get('permalink', '')

# Default timing label
timing_label = ''

if due_raw and completed_raw:
    try:
        due_date = datetime.strptime(due_raw, '%Y-%m-%d')
        # Completed date comes as ISO 8601 — strip time component
        completed_date = datetime.strptime(completed_raw[:10], '%Y-%m-%d')
        delta = (completed_date - due_date).days
        if delta > 0:
            timing_label = f'⚠️ ({delta} day{"s" if delta > 1 else ""} late)'
        elif delta == 0:
            timing_label = '✅ On time'
        else:
            timing_label = f'🚀 {abs(delta)} day{"s" if abs(delta) > 1 else ""} early'
    except ValueError:
        timing_label = ''

# Compose the final Slack message
message = (
    f'✅ *Milestone Complete:* {task_name}\n'
    f'*Project:* {project_name}\n'
    f'*Completed by:* {assignee}\n'
    f'*Due date:* {due_raw} {timing_label}\n'
    f'🔗 View in Asana: {permalink}'
)

output = [{'slack_message': message, 'timing_label': timing_label}]

Zap Editor > Action > Test Action > Publish

Test and activate the Zap

Click 'Test action' in the Slack step — Zapier will post a real test message to your selected Slack channel using the sample Asana data. Go to Slack and verify the message looks correct: readable date, proper milestone name, working link, and the right channel. If anything looks off, click back into the Slack action and edit the message text. Once the test message looks right, click 'Publish' at the top of the Zap editor to turn it on. The Zap is now live and polling Asana every 1-15 minutes depending on your plan.

1. 1Click 'Test action' in the Slack step
2. 2Check your Slack channel for the test message
3. 3Review the message for formatting, data accuracy, and link validity
4. 4Click 'Back' to edit if anything needs adjustment
5. 5Click 'Publish' to activate the Zap