GPTHotline

Enables real-time chat with GPT models directly through WhatsApp's messaging interface by routing user messages to OpenAI's API backend and streaming responses back as WhatsApp messages. Uses WhatsApp Business API webhooks to receive incoming messages, processes them through OpenAI's chat completion endpoints, and formats responses within WhatsApp's 4096-character message limit, maintaining conversation context across multiple message exchanges within a single chat thread.

Leverages GPT's text generation capabilities to produce written content (emails, social posts, blog outlines, creative copy) directly from WhatsApp prompts. Routes user requests through OpenAI's GPT models with system prompts optimized for content creation tasks, returning formatted output within WhatsApp's message constraints. Supports iterative refinement through follow-up messages in the same conversation thread.

Processes user queries through GPT to retrieve, synthesize, and summarize information based on GPT's training data and knowledge cutoff. Does not perform live web search—instead relies on GPT's parametric knowledge to answer factual questions, explain concepts, and provide summaries. Responses are constrained by GPT's training data recency and accuracy limitations, delivered as WhatsApp messages.

Maintains conversation state across multiple WhatsApp messages by storing and referencing prior messages within a single chat thread. Implements context management by passing previous message history to GPT's API with each new request, allowing the model to understand references, follow-ups, and multi-turn dialogue. Context window is limited by OpenAI's token limits and GPTHotline's backend state management (likely storing recent message history in a database keyed by WhatsApp chat ID).

Implements tiered access control where paid subscribers receive defined message quotas and rate limits enforced by GPTHotline's backend. Tracks API usage per WhatsApp account (keyed by phone number), enforces rate limits (e.g., messages per hour/day), and gates access to GPT models based on subscription tier. Likely uses a metering service to count API calls to OpenAI and bill users accordingly, with quota exhaustion triggering error messages in WhatsApp.

Implements server-side webhook handlers that receive incoming WhatsApp messages via the WhatsApp Business API, parse message payloads, route them to OpenAI's API, and send responses back through WhatsApp's message sending API. Uses OAuth or API key authentication to WhatsApp Business API, implements idempotency handling for duplicate webhook deliveries, and manages message delivery status callbacks. Architecture likely uses a message queue (e.g., Redis, RabbitMQ) to buffer incoming messages and ensure reliable delivery to OpenAI.

Enables users to refine GPT outputs through follow-up messages that modify tone, length, format, or content direction. Implements refinement by passing the original prompt, initial response, and refinement request to GPT as a new conversation turn, allowing the model to adjust output based on user feedback. Supports common refinement patterns like 'make it shorter', 'more formal', 'add examples', etc., which are interpreted as natural language instructions to GPT.

Processes incoming WhatsApp messages to extract text content, handle special characters, emojis, and formatting, and normalize input for GPT processing. Handles WhatsApp-specific message types (text, media captions, quoted replies) and converts them to plain text suitable for GPT. Formats GPT responses to fit WhatsApp's 4096-character limit by implementing smart text splitting (e.g., breaking at sentence boundaries) and sending multi-message sequences when needed.