whatsapp-formatter 0.1.0

Transform LLM output to WhatsApp Business API JSON format

WhatsApp Formatter

Transform LLM output to WhatsApp Business API JSON format.

This library uses an LLM to parse free-form text (with options, headers, footers) and automatically converts it to valid WhatsApp message formats (plain text, quick reply buttons, or interactive lists).

Installation

pip install whatsapp-formatter

Quick Start

import os
from whatsapp_formatter import format_for_whatsapp

# Set your API key (OpenRouter or OpenAI)
os.environ["OPENROUTER_API_KEY"] = "your-api-key"
os.environ["OPENROUTER_BASE_URL"] = "https://openrouter.ai/api/v1"

# Format LLM output for WhatsApp
raw_text = """
I can help with your account. What would you like to do?

1. Check your balance
2. Transfer funds
3. View recent transactions
"""

result = format_for_whatsapp(raw_text)
print(result.whatsapp_json)

Output:

{
  "type": "interactive",
  "interactive": {
    "type": "button",
    "body": { "text": "I can help with your account. What would you like to do?" },
    "action": {
      "buttons": [
        { "type": "reply", "reply": { "id": "check_your_balance", "title": "Check your balance" } },
        { "type": "reply", "reply": { "id": "transfer_funds", "title": "Transfer funds" } },
        { "type": "reply", "reply": { "id": "view_recent_transac", "title": "View Transactions" } }
      ]
    }
  }
}

Features

• Automatic format selection based on option count:

  • 0 options → Plain text message
  • 1-3 options → Quick reply buttons
  • 4-10 options → Interactive list
  • 11+ options → Plain text fallback with numbered list

• Smart truncation to fit WhatsApp constraints:

  • Button titles: max 20 characters
  • List row titles: max 24 characters
  • Body text: max 1024 characters (interactive) or 1600 (plain text)

• Automatic deduplication of option titles with suffixes

• Header/footer extraction from structured messages

• Multiple option formats supported:

  • Numbered lists (1. Option)
  • Bullet points (- Option, • Option)
  • Inline choices (Yes, No, or Cancel)

API Reference

format_for_whatsapp(text: str) -> TransformResult

The main entry point. Parses text and returns WhatsApp-ready JSON.

from whatsapp_formatter import format_for_whatsapp

result = format_for_whatsapp("Your balance is $500.")
print(result.format_used)      # FormatType.PLAIN_TEXT
print(result.whatsapp_json)    # {"type": "text", "text": {"body": "..."}}
print(result.fallback_used)    # False
print(result.modifications)    # List of any truncations applied

transform(llm_output: LLMOutput) -> TransformResult

Transform pre-parsed data to WhatsApp format (skip LLM parsing step).

from whatsapp_formatter import transform, LLMOutput, Option

llm_output = LLMOutput(
    body="Choose an option:",
    options=[
        Option(title="Yes"),
        Option(title="No"),
    ]
)
result = transform(llm_output)

parse(text: str) -> LLMOutput

Parse text using LLM (requires API key).

from whatsapp_formatter import parse

llm_output = parse("Select: 1. Apple 2. Banana 3. Cherry")
print(llm_output.body)     # "Select:"
print(llm_output.options)  # [Option(title="Apple"), ...]

Data Types

LLMOutput

class LLMOutput:
    body: str                    # Main message text (required)
    options: list[Option] | None # Flat list of options
    sections: list[Section] | None # Grouped options (for list format)
    header: str | None           # Optional header text
    footer: str | None           # Optional footer text

TransformResult

class TransformResult:
    success: bool                # Always True unless error
    whatsapp_json: dict          # Ready-to-send WhatsApp payload
    format_used: FormatType      # PLAIN_TEXT, QUICK_REPLY, or LIST
    fallback_used: bool          # True if format was downgraded
    fallback_reason: str | None  # Reason for fallback
    modifications: list[str]     # Truncations/deduplications applied

FormatType

class FormatType(Enum):
    PLAIN_TEXT = "plain_text"
    QUICK_REPLY = "quick_reply"
    LIST = "list"

Configuration

Environment Variables

Variable	Description	Required
OPENROUTER_API_KEY	OpenRouter API key	Yes*
OPENAI_API_KEY	OpenAI API key	Yes*
OPENROUTER_BASE_URL	API base URL	No
OPENROUTER_MODEL	Model to use (default: openai/gpt-4o-mini)	No

*One of OPENROUTER_API_KEY or OPENAI_API_KEY is required.

Recommended Models

For best results with structured extraction:

• qwen/qwen3-30b-a3b-instruct-2507 (91%+ accuracy)
• openai/gpt-4o-mini (with JSON mode)

WhatsApp Constraints

The library automatically handles these WhatsApp Business API limits:

Element	Max Length
Quick reply button title	20 chars
Quick reply buttons	3 max
List row title	24 chars
List row description	72 chars
List sections	10 max
List rows total	10 max
Interactive body	1024 chars
Plain text body	1600 chars
Header	60 chars
Footer	60 chars

Examples

Plain Text (no options)

result = format_for_whatsapp("Your balance is $500.")
# → {"type": "text", "text": {"body": "Your balance is $500."}}

Quick Reply (1-3 options)

result = format_for_whatsapp("""
Was this transaction authorized?
1. Yes
2. No
""")
# → {"type": "interactive", "interactive": {"type": "button", ...}}

List (4-10 options)

result = format_for_whatsapp("""
Select a service:
1. Balance
2. Transfer
3. Cards
4. Loans
5. Support
""")
# → {"type": "interactive", "interactive": {"type": "list", ...}}

With Header and Footer

result = format_for_whatsapp("""
⚠️ Security Alert

We detected a login from a new device. Was this you?

1. Yes, it was me
2. No, secure my account

Reply within 24 hours.
""")
# Extracts header: "Security Alert"
# Extracts footer: "Reply within 24 hours."

Development

# Clone the repository
git clone https://github.com/dnivra26/whatsapp-formatter.git
cd whatsapp-formatter

# Install with dev dependencies
pip install -e ".[dev]"

# Run tests
pytest

License

MIT License