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Transcribe voice messages and classify intent with OpenAI Whisper and GPT-4o-mini

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Transcribe voice messages and classify intent with OpenAI Whisper and GPT-4o-mini preview
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1. Workflow Overview

Quick overview This workflow downloads an audio file, transcribes it with OpenAI Whisper, classifies the transcript intent using OpenAI GPT 4o mini, and returns a simple response message based on t...

Best for

  • Support Chatbot automation workflows
  • AI Summarization automation workflows
  • intermediate n8n builders looking for reusable templates

Tools used

n8n-nodes-base.manualtrigger, n8n-nodes-base.set, n8n-nodes-base.httprequest, @n8n/n8n-nodes-langchain.openai, n8n-nodes-base.stickynote, n8n-nodes-base.switch

Source and attribution

This workflow is cataloged by N8N Workflows and links back to its original n8n.io source page by Luis R..

Original n8n.io source

1.1 Workflow description

Title
Transcribe voice messages and classify intent with OpenAI Whisper and GPT-4o-mini
Workflow name
Transcribe voice messages and classify intent with OpenAI Whisper and GPT-4o-mini

Quick overview

This workflow downloads an audio file, transcribes it with OpenAI Whisper, classifies the transcript intent using OpenAI GPT-4o-mini, and returns a simple response message based on the detected category.

How it works

  1. Runs when you manually execute the workflow.
  2. Sets a sample audio URL (JFK .flac) and downloads the audio file via an HTTP request.
  3. Sends the audio file to OpenAI Whisper to generate a text transcription.
  4. Passes the transcript to OpenAI GPT-4o-mini to classify it as GREETING, QUESTION, REQUEST, or OTHER.
  5. Normalizes the model output to an uppercase intent value and routes execution based on the intent.
  6. Returns a predefined response message for the matched intent branch.

Setup

  1. Add OpenAI API credentials for both the Whisper transcription step and the GPT-4o-mini intent classification step.
  2. Replace the sample audio URL with your own audio source, or swap the manual trigger for a webhook that provides an audio URL.
  3. If you use a different audio format, ensure the downloaded file is a supported type for OpenAI transcription (and adjust the MIME type/value if you rely on it elsewhere).

Customization

  • Connect to any WhatsApp gateway — Evolution API, Twilio, or WhatsApp Cloud API
  • Add custom intent categories to match your business (COMPLAINT, APPOINTMENT, PRICING)
  • Route each intent to a different workflow — CRM update, human escalation, auto-reply
  • Swap GPT-4o-mini for Claude Haiku to reduce costs on high-volume deployments
  • Extend with RAG to give context-aware responses based on your knowledge base

Additional info

This workflow is a simplified extract from a production multi-tenant WhatsApp AI system handling real customer conversations.

Built with: n8n · OpenAI Whisper · GPT-4o-mini · Evolution API · Docker · Oracle Cloud

Tags: whatsapp, voice, audio, transcription, whisper, intent, classification, chatbot, ai-agent, automation, openai, gpt4o-mini, customer-support, nlp

1.2 Logical Blocks

This catalog entry is organized from the workflow JSON. The node-level section below shows the executable blocks available for review before importing the template.

2. Block-by-Block Analysis

Block 1 - When clicking ‘Execute workflow’

Type / Role
n8n-nodes-base.manualTrigger - manualTrigger
Config choices
Version 1

Block 2 - Sample Audio (JFK)

Type / Role
n8n-nodes-base.set - set
Config choices
Version 3.4

Block 3 - Download Audio

Type / Role
n8n-nodes-base.httpRequest - httpRequest
Config choices
Version 4.4

Block 4 - Whisper Transcription1

Type / Role
@n8n/n8n-nodes-langchain.openAi - openAi
Config choices
Version 2.1

Block 5 - Edit Fields

Type / Role
n8n-nodes-base.set - set
Config choices
Version 3.4

Block 6 - Sticky Note

Type / Role
n8n-nodes-base.stickyNote - stickyNote
Config choices
Version 1

Block 7 - Extract Intent

Type / Role
n8n-nodes-base.set - set
Config choices
Version 3.4

Block 8 - Route by Intent

Type / Role
n8n-nodes-base.switch - switch
Config choices
Version 3.4

Block 9 - Response - Greeting

Type / Role
n8n-nodes-base.set - set
Config choices
Version 3.4

Block 10 - Response - Question

Type / Role
n8n-nodes-base.set - set
Config choices
Version 3.4

Block 11 - Response - Request

Type / Role
n8n-nodes-base.set - set
Config choices
Version 3.4

Block 12 - Response - Others

Type / Role
n8n-nodes-base.set - set
Config choices
Version 3.4

Block 13 - Intent Classifier

Type / Role
@n8n/n8n-nodes-langchain.openAi - openAi
Config choices
Version 2.1

3. Summary Table

Workflow Transcribe voice messages and classify intent with OpenAI Whisper and GPT-4o-mini
Complexity intermediate
Nodes 13
Categories Support Chatbot, AI Summarization
Author Luis R.
Published 24 May 2026

4. Reproducing the Workflow from Scratch

  1. 1. Download the workflow JSON

    Use the JSON export at /data/workflows/15927/15927.json as the source template for this automation.

  2. 2. Import the template into n8n

    Open n8n, import the downloaded JSON, and review each node before activating the workflow.

  3. 3. Configure credentials and variables

    Replace placeholder credentials, API keys, webhook URLs, account IDs, and environment-specific values with your own settings.

  4. 4. Test with sample data

    Run the workflow manually or in a staging workspace, inspect node output, and confirm downstream systems receive the expected data.

  5. 5. Activate and monitor

    Enable the workflow only after testing, then monitor executions, errors, and rate limits during the first production runs.

5. General Notes & Resources

Review imported nodes carefully before activation. This catalog entry is intended to help you inspect the workflow structure, understand required services, and find related templates faster.

Node names, credentials, schedules, webhook paths, and external service limits may need adjustment for your workspace.

Frequently asked questions

What does Transcribe voice messages and classify intent with OpenAI Whisper and GPT-4o-mini do?

Quick overview This workflow downloads an audio file, transcribes it with OpenAI Whisper, classifies the transcript intent using OpenAI GPT 4o mini, and returns a simple response message based on t...

What do I need before importing this workflow?

Review the workflow JSON, configure any required credentials in n8n, and test the automation in a safe workspace before using it in production.

Can I customize this workflow?

Yes. Use the block-by-block analysis and the downloadable JSON to inspect each node, then adjust credentials, prompts, schedules, filters, or destinations for your Support Chatbot, AI Summarization use case.