Lemlist replies sorted by AI and sent to HubSpot and Slack

Lemlist replies sorted by AI and sent to HubSpot and Slack

An n8n workflow that reads the first reply a lead sends to a lemlist campaign and sorts it with an OpenAI model. A
positive reply marks the lead as interested in lemlist, makes a HubSpot deal and posts a Slack message. An out of office
reply makes a HubSpot follow-up task. An unsubscribe takes the lead out of the campaign. Anything else goes to Slack.

What is inside

• workflow.json: the workflow as n8n exports it, 13 nodes and no sticky note. It holds no credential.
• README.md: these notes.
• The original copy had stray text after its JSON, which Mindket's copy drops.

What we changed from the original copy

• The reply was sorted by n8n's legacy OpenAI text node, which sends a completion request and has no model set, so it
  used gpt-3.5-turbo-instruct. OpenAI shut that model down on 28 September 2026, and its replacement does not take
  completion requests. The step is now Classify reply with OpenAI, a Basic LLM Chain, with an OpenAI Chat Model set
  to gpt-5.6-terra. The old limit of 6 tokens and the temperature of 0 are not carried over. A system message asks for
  the category name only.
• The prompt listed the categories in lower case, while Switch compares exact text and expects Interested,
  Out of Office and Unsubscribe. The prompt now uses those spellings, and Other for the rest.
• lemlist Mark as interested had a typed YOUR_CAMPAIGN_ID in its address. It now takes the campaign from the reply,
  as Lemlist Unsubscribe does.
• HubSpot Create Deal held its author's deal stage ID, and Slack held its author's HubSpot account number in the link.
  They are now YOUR_DEAL_STAGE_ID and YOUR_HUBSPOT_PORTAL_ID.
• Six node names lost a spaced hyphen. The trigger is now Lemlist Lead Replied and the deal node is `HubSpot Create
  Deal`. The other four follow the same pattern.
• Every credential reference is removed, so you pick your own.

Before you start

• An n8n instance with a public address, on n8n Cloud or your own server, because lemlist posts each reply to it.
• A lemlist account with an API key and a running campaign.
• An OpenAI API key.
• A HubSpot account and a HubSpot OAuth2 credential.
• A Slack workspace, a channel and a Slack OAuth2 credential.

Set it up

1. In n8n, create a workflow, open its menu and choose Import from File. Pick workflow.json.
2. Add a lemlist credential with your API key. Select it in Lemlist Lead Replied, Lemlist Unsubscribe and
   lemlist Mark as interested.
3. Add an OpenAI credential and select it in OpenAI Chat Model.
4. Add a HubSpot OAuth2 credential. Select it in HubSpot Get contact ID, HubSpot Get contact ID1,
   HubSpot Create Deal and follow up task.
5. Add a Slack credential and select it in Slack and Slack1. In both, replace Your channel name with your channel.
6. In HubSpot Create Deal, choose the deal stage that replaces YOUR_DEAL_STAGE_ID.
7. In Slack, replace YOUR_HUBSPOT_PORTAL_ID with your HubSpot account number. It follows /contacts/ in your HubSpot
   address, and the link uses the EU server app-eu1, so change that part if your account lives elsewhere.
8. To watch one campaign, set it in the options of Lemlist Lead Replied. Without it, every campaign of your team is
   watched.
9. Save and press Publish. Publishing makes n8n register its webhook in lemlist. Send a test reply to a test lead.

How a run goes

1. Lemlist Lead Replied fires on the first reply of a lead, because its Is First option is on.
2. Classify reply with OpenAI reads the reply text with the line breaks removed and answers with a category.
3. Merge puts the category in the text field, over the reply text, and keeps the lead's other fields.
4. Switch sends the item down one of four lines. Unsubscribe, Interested and Out of Office match exactly. Anything
   else takes the last line.
5. Unsubscribe: Lemlist Unsubscribe removes the lead from the campaign.
6. Interested: lemlist Mark as interested flags the lead in lemlist. At the same time HubSpot Get contact ID finds or
   creates the contact by email with the lead's names, HubSpot Create Deal opens a deal and links it to that contact, and
   Slack posts a message with a link to the deal.
7. Out of Office: HubSpot Get contact ID1 finds or creates the contact and follow up task adds a HubSpot task for it.
   The task subject starts with OOO and holds the contact's name.
8. Other: Slack1 posts that a lead replied, with a link to the campaign report in lemlist.

Change the look

• The categories: the system message in Classify reply with OpenAI and the rules in Switch. Keep the spellings equal.
• The deal: the name and the stage in HubSpot Create Deal.
• The messages: the text of Slack and Slack1.
• The task: the subject of follow up task.
• The model: OpenAI Chat Model.
• Which replies count: the Is First option and the campaign in Lemlist Lead Replied.

Good to know

• An answer that is not exactly one of the three names goes down the last line and reaches Slack1. A wrong answer in
  the first line removes a lead from the campaign, so read the first results before you trust them.
• gpt-5.6-terra is the replacement that OpenAI's deprecations page names for gpt-3.5-turbo-instruct.
• lemlist's developer pages, read on 12 November 2026, call API version 1 deprecated and name version 2 as the one to use.
  The pages for the campaign unsubscribe and mark as interested requests carry no deprecation note. lemlist's help
  article says the old /unsubscribes routes stop on 1 November 2026, and this workflow does not use them.
• HubSpot's legacy API page, read on 12 November 2026, says the numeric versions v1 to v4 will be deprecated in a future
  release and gives no date. The HubSpot nodes here are version 1, which uses the v1 contacts, deals and engagements APIs.
• HubSpot Get contact ID and its twin create the contact when the email is new, or update its names when it exists.
• The trigger is set to the first reply only, so a lead's later replies start nothing.
• OpenAI bills one model call for each first reply, and each reply's text goes to OpenAI.
• Lead details go to HubSpot and Slack.