Edit Template
SuprSend provides two ways to design Slack templates:- Text Editor: For simple text-based messages with variable interpolation
- JSONNET Editor: For rich, interactive templates using Slack’s Block Kit with buttons, images, and complex layouts
Text Editor
The text editor is ideal for simple text messages with variable content. You can add variables in Handlebars syntax as{{...}}
. If the output has special html text, enclose variable in triple curly braces as {{{url}}}
to avoid HTML escaping.
JSONNET Editor
The JSONNET editor enables rich template design using Slack Block Kit Builder. This allows you to create interactive templates with buttons, images, checkboxes, and styled text. It is essentially JSON template where variables can be added in JSONNET syntax asdata.variable_name
or data["$variable_name"]
.

Template Examples
1. Simple Text Template
1. Simple Text Template

2. With Buttons: Approval Request
2. With Buttons: Approval Request
3. With Image: Anomaly Alert
3. With Image: Anomaly Alert

4. With Array List: Pending Task Digest (Batched Alert)
4. With Array List: Pending Task Digest (Batched Alert)

Adding dynamic content
Here’s how you can different types of variables in both handlebars and JSONNET syntax.Variable Type | Handlebars Syntax | JSONNET Syntax |
---|---|---|
Parent Level variables | {{user_name}} | data.user_name |
Nested Object | {{org.name}} | data.org.name |
Print Array element at Index | {{task_list.[0].task_name}} | data.task_list[0].task_name |
Recipient | {{$recipient.name}} | data["$recipient"].name |
Actor | {{$actor.name}} | data["$actor"].name |
Tenant | {{$tenant.brand_name}} | data["$tenant"].brand_name |
Preview Template
- Add mock JSON data using the
Mock data
button for all variables used in the template - Click
Load Preview
to see the rendered template - For JSONNET templates, click
View in Slack Block Kit
to see the actual Slack UI preview
You must add mock data for all variables in your template. Missing mock data will cause rendering errors and prevent the preview from loading.

Publish Template
Once your template is ready, click Publish Draft and provide a version name to publish it. The published template becomes the live version and will be used whenever the associated workflow is triggered.Test Template
Use this option to send a test message in Slack and preview how it will appear in user’s device. Click the Test button, then enter the user’s distinct_id and select the Slack channel where the test message should be sent.Template testing only uses the published Live version, so make sure to publish your changes before testing.
Promote to Production
You can clone template across workspaces by using Clone -> Outside Template option. Clone -> Within template can be used to clone within different languages and versions of the same template.Best Practice: Always design templates in your staging workspace first, then promote them to production. This ensures thorough testing of the changes without impacting end users.