# Route human-in-the-loop approval requests with Slack: n8n workflow

> Started by another system calling it, and works across Postgres and Slack. 17 steps, 2 branches: a working afternoon to understand properly.

Source: https://millionrounds.com/workflow/route-human-in-the-loop-approval-requests-with-slack (Millionrounds; every figure on the page links to its filing or article)

[Automation library](https://millionrounds.com/workflows) · [Content](https://millionrounds.com/workflows?category=Content#library)

# Route human-in-the-loop approval requests with Slack

Started by another system calling it, and works across Postgres and Slack. 17 steps, 2 branches: a working afternoon to understand properly.

Medium

[Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Froute-human-in-the-loop-approval-requests-with-slack)

**17 steps** Medium: a working afternoon

**2** Branches: places the flow splits

**0** Loops or waits

**2** Services it connects to

## The flow

Starts it 3 Logic 9 Service 5

The steps in the order they run, from what starts it.

- 1 **Receive Slack POST Request** Webhook *Starts it*
- 2 **Verify Slack Request Signature** Code *Logic*
- 3 **Determine Slack Request Type** Code *Logic*
- 4 **Route by Request Type** If *Logic*
- 5 **Create Slack Block Message** Code *Logic*
- 6 **Handle Slack Callback Data** Code *Logic*
- 7 **Send Message to Slack Channel** Slack *Service*
- 8 **Acknowledge Slack Callback Fast** Respond To Webhook *Starts it*
- 9 **Check Slack Response Validity** Code *Logic*
- 10 **Retrieve Context from Database** Postgres *Service*
- 11 **Log Request in Database** Postgres *Service*
- 12 **Combine Callback with DB Context** Code *Logic*
- 13 **Acknowledge Intake with 200 OK** Respond To Webhook *Starts it*
- 14 **Update Slack Message Content** Code *Logic*
- 15 **Modify Slack Message to Final** Slack *Service*
- 16 **Record Decision in Database** Postgres *Service*
- 17 **Determine Next Action Taken** If *Logic*

## How it's built

- **Starts on:** Another system calling it
- **Steps:** 17, with 2 branches
- **Size:** Medium: a working afternoon
- **Connects to:** Postgres, Slack
- **Model:** None. This is plumbing, not judgement

## Questions

What does it need to run?

An n8n account, plus your own Postgres and Slack accounts. You connect your own accounts after importing it; none are included.

What starts it?

It starts on another system calling it.

Does it use AI?

No. Every step is fixed logic or a call to a service, so it does the same thing every time.

How long does it take to set up?

Plan an afternoon. 17 steps is enough that you should read each one before running it.

How do I import it?

Copy the workflow, open a new workflow in n8n and paste. The steps appear on the canvas, ready for your own accounts.

**Before you run it**

Nothing here has been tested by us. It is somebody's working automation, read and described from its own steps. Treat the connections it wants as a list of accounts it will touch, and read the 17 steps before you point it at anything that matters.

## Run it in n8n

- **Create your n8n account** Free to start. n8n is where the workflow runs. [Create an n8n account ↗](https://millionrounds.com/n8n)
- **Download the workflow** Free with a Millionrounds account. [Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Froute-human-in-the-loop-approval-requests-with-slack)
- **Paste it into n8n** Open a new workflow in n8n and paste. Then connect your own accounts.

Stored with the author's traces removed: canvas notes, instance identifiers, saved credential names and any live document they had left behind.

## Connects to

Each opens the other workflows that use it.

[Postgres](https://millionrounds.com/workflows?service=Postgres#library)[Slack](https://millionrounds.com/workflows?service=Slack#library)

## Workflows like it

Also content, with the same services where possible, closest in size first.

- [**Turn forwarded business document images into structured records** 17 steps · Gmail, Postgres](https://millionrounds.com/workflow/turn-forwarded-business-document-images-into-structured-reco)
- [**Add internal links to WordPress posts with OpenAI and Notion** 17 steps · calls a model · Notion, Slack](https://millionrounds.com/workflow/add-internal-links-to-wordpress-posts-with-openai-and-notion)
- [**Create daily AI and blockchain social posts with SerpAPI** 17 steps · calls a model · Google Drive, Google Sheets](https://millionrounds.com/workflow/create-daily-ai-and-blockchain-social-posts-with-serpapi)
- [**Daily space image gallery with Google Drive** 17 steps · calls a model · Google Drive, Slack](https://millionrounds.com/workflow/daily-space-image-gallery-with-google-drive)
- [**Generate multilingual audio content with OpenAI and ElevenLabs** 17 steps · calls a model · Google Drive, Slack](https://millionrounds.com/workflow/generate-multilingual-audio-content-with-openai-and-elevenla)
- [**Long-Form Content into Social Snippets with OpenAI** 17 steps · calls a model · Airtable, Slack](https://millionrounds.com/workflow/long-form-content-into-social-snippets-with-openai)