Convert Telegram Voice Messages to Professional Emails with Whisper, GPT-4 & Gmail

Created by

Baptiste Fort

Last update

Last update a day ago

Telegram Voice Message → Automatic Email

Imagine: What if you could turn a simple Telegram voice message into a professional email—without typing, copying, pasting, or even opening Gmail?

This workflow does it all for you: just record a voice note, and it will transcribe, format, and write a clean HTML email, then send it to the right person—all by itself.

Prerequisites

Create a Telegram bot (via BotFather) and get the token.
Have an OpenAI account (API key for Whisper and GPT-4).
Set up a Gmail account with OAuth2.
Import the JSON template into your automation platform.

🧩 Detailed Flow Architecture

1. Telegram Trigger

Node: Telegram Trigger
This node listens to all Message events received by the specified bot (e.g., “BOT OFFICIEL BAPTISTE”).
Whenever a user sends a voice message, the trigger fires automatically.

⚠️ Only one Telegram trigger per bot is possible (API limitation).

Key parameter:

Trigger On: Message

2. Wait

Node: Wait
Used to buffer or smooth out calls to avoid collisions if you receive several voice messages in a row.

3. Retrieve the Audio File

Node: Get a file

Type: Telegram (resource: file)
Parameter:
- fileId = {{$json["message"]["voice"]["file_id"]}}
  This node fetches the voice file from Telegram received in step 1

4. Automatic Transcription (Whisper)

Node: Transcribe a recording

Resource: audio
Operation: transcribe
API Key: Your OpenAI account
The audio file is sent to OpenAI Whisper: the output is clean, accurate text ready to be processed.

5. Optional Wait (Wait1)

Node: Wait1
Same purpose as step 2: useful if you want to buffer or add a delay to absorb processing time.

6. Structured Email Generation (GPT-4 + Output Parser)

Node: AI Agent
This is the core of the flow:

The transcribed text is sent to GPT-4 (or GPT-4.1-mini here, via OpenAI Chat Model)

Prompt used:

You are an assistant specialized in writing professional emails.

Based on the text below, you must: {{ $json.text }}

1. Detect if there is a recipient's email address in the text (or something similar like "send to fort.baptiste.pro")
   - If it’s not a complete address, complete it by assuming it ends with `@gmail.com`.
2. Understand the user's intent (resignation, refusal, application, excuse, request, etc.)
3. Generate a relevant and concise email subject, faithful to the content
4. Write a professional message, structured in HTML:
   - With a polite tone, adapted to the situation
   - Formatted with HTML tags (`&lt;p&gt;`, `&lt;br&gt;`, etc.)
   - No spelling mistakes in French
   - My first name is jeremy and if the text says he is not happy, specify the wish to resign

⚠️ You must always return your answer in the following strict JSON format, with no extra text:
```

```json
{
  "email": "[email protected]",
  "subject": "Objet de l’email",
  "body": "&lt;p&gt;Contenu HTML de l’email&lt;/p&gt;"
}
```

Everything is strictly validated and formatted with the Structured Output Parser node.

7. Automatic Email Sending (Gmail)

Node: Send a message

To: {{$json.output.email}}
Subject: {{$json.output.subject}}
HTML Body: {{$json.output.body}}
This node takes the JSON structure returned by the AI and sends the email via Gmail, to the right recipient, with the correct subject and full HTML formatting.