Slack

Renta posts rows from your data warehouse to a Slack channel: a message for every row that changed, several rows per message, a text table, or a CSV file.

You write the message once as a template with {{ column }} placeholders, and Renta fills it in for every row. A changed row can show the previous value next to the new one.

Authentication

Renta authenticates with Slack OAuth. The authorization is per workspace, so pick the Slack workspace the pipeline should post into.

Slack asks for permission to list public and private channels, post messages, post to public channels the bot has not joined, post under a custom name and icon, and upload files. Renta reads the channel list to fill the Channel dropdown and uses the other permissions when a pipeline runs.

To post into a private channel, open the channel in Slack and type /invite @Renta. Public channels need no invitation.

Prepare a data model

A Reverse ETL pipeline reads from a data model: a SQL query saved in the Context layers section that decides which warehouse rows to sync and what each row holds. Build it before the pipeline, because the template editor and the column mapper are filled from its columns.

Name the columns the way you want to reference them in a message. A column named email is inserted as {{ email }}. A column whose name has spaces or starts with a digit is still available as {{ row["signup date"] }}.

Mark the column that identifies a row as the key when you save the model. In Message mode Renta uses the key to tell a changed row from a new one. The steps are the same for every warehouse, see Create a data model.

Pipeline configuration

On the final step, choose how Renta posts the rows, where they go, and what each message says. The form adapts to the mode you pick, so choose it first.

How Renta sends your data

Pick one of four modes. The first one follows changes in the model. The other three post the whole model result on every run.

Data model and channel

Point the pipeline at the data and at the channel.

1. Data model.
   Choose the data model to send. Renta reads the rows and the column names from it.
2. Channel.
   Choose the channel to post into. The list holds the public channels of the workspace and the private channels the bot was invited to.
3. Channel from a column.
   Available in Message mode. Pick a column that holds a Slack channel ID, such as C0123456789, to route each row to its own channel. A row whose value is empty is skipped and reported in the run log. The bot has to be able to post into every channel the column names.

Message format and first run

Choose how Renta reads your templates and what the first run does with the rows that already exist.

1. Message format Choose the syntax of the templates.

   Format	Description
   Plain text	Renta sends the rendered template as the message text. Slack formatting works: *bold*, _italic_, <https://example.com|link text>, and <@USER_ID> mentions.
   Slack Block Kit	The template is a JSON array of Block Kit blocks. Renta checks that it is valid JSON when you save and fills the placeholders for every row. Use mrkdwn text objects inside the blocks.

2. First run Available in Message mode.

   Option	Description
   Skip existing rows	The first run records the rows and posts nothing. Messages start with the next change. This is the default.
   Send a message for every row	The first run posts the "row added" message for every row in the model.

Message templates

In Message mode you write up to three templates, one per kind of change. Type {{ in the editor to pick a column or a variable, or click a chip under the editor. The counter in the corner shows the template length against the limit of 4,000 characters.

Besides the model columns, every template can use the run variables.

Renta escapes the characters &, <, and > in column values, so a value that looks like markup is shown as text. If a column already holds Slack markup, such as a ready link, add the safe filter: {{ link_column | safe }}.

Removed rows and the bot

Finish the message settings with the removed-row template and the look of the bot.

1. Message when a row is removed.
   Posted for a row that left the model. The template sees the last known values of the row.
2. Bot name.
   Renta posts under this name, up to 80 characters. Leave it empty to post under the Slack app name.
3. Bot icon emoji.
   An emoji code with the colons, such as :chart_with_upwards_trend:. Leave it empty to keep the app icon.

When a source row is deleted

Set what happens in Slack when a row disappears from the data model. The setting is available in Message mode.

Then name the pipeline. Integration name is the name of your pipeline. Edit it to match your preferences.

Batch message

In Batch message mode Renta renders the body template for every row and groups the rows into messages.

1. Rows per message.
   How many rows go into one message, from 1 to 50.
   Default: 10
2. Message header.
   Text at the top of each message. The header sees the run variables, such as {{ model_name }}, but not the columns.

3. Text for each row.
   The template Renta repeats once per row. Required.
4. Message footer.
   Text at the bottom of each message. Like the header, it sees the run variables only.

A message whose rows render to more than 4,000 characters is rejected with a hint to lower Rows per message. In Slack Block Kit format the row template has to render to a JSON array of blocks. The header and the footer become section blocks around the rows, and a message carries at most 50 blocks.

Table and CSV

In Table and CSV modes there are no templates. Map the model columns to the columns of the table or the file instead.

All model columns are mapped when the pipeline is created. Remove the ones you don't need, rename the headers, or use Add mapping to add more:

In Table mode Renta posts the result as a monospaced table in one or more messages, with the header row in each message. A cell longer than 60 characters is cut with an ellipsis. In CSV mode Renta uploads one file named after the model and the run date, for example signups_2026-10-21.csv, with the headers in the first row. In both modes the optional Message header is posted as the text above the table or the file.

Schedule

Choose how often the pipeline runs.

For Daily schedules, set the Update time (the exact time each run starts), then click Create pipeline.

The new pipeline appears in the Pipelines section under the Reverse ETL tab, where you can track its runs and progress.

Sync strategy

In Message mode Renta syncs incrementally. A run compares the data model against the state the previous run recorded and posts a message only for the rows that moved. The first run has nothing to compare against, so it records the rows and posts nothing, unless First run is set to post every row.

Batch message, Table, and CSV post the whole result of the model on every run, whether the rows changed or not.

Limits

The table lists the ceilings a run can hit and what Renta does when it happens.