> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chat402.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Whitepaper

> Chat402 Technical Whitepaper - Privacy-First Pay-Per-Use AI

# Chat402 Whitepaper

The Chat402 whitepaper provides a comprehensive technical overview of our privacy-first, pay-per-use AI platform built on Solana.

## Download

<Card title="Download Whitepaper (PDF)" icon="download" href="https://www.chat402.xyz/whitepaper.pdf">
  Version 6 - December 2025
</Card>

## Key Topics Covered

<CardGroup cols={2}>
  <Card title="Privacy Model" icon="shield-check">
    How Chat402 achieves true privacy through client-side storage and zero server-side data retention.
  </Card>

  <Card title="Payment Mechanism" icon="wallet">
    SPL token delegation for seamless, signless micropayments on Solana.
  </Card>

  <Card title="Game Theory" icon="chess">
    Economic incentives that align user, operator, and network interests.
  </Card>

  <Card title="Technical Architecture" icon="diagram-project">
    System design including API gateway, payment verification, and model routing.
  </Card>
</CardGroup>

## Abstract

Chat402 is a privacy-first LLM API gateway that enables anonymous access to frontier AI models through cryptocurrency micropayments. Unlike traditional AI services that require accounts, collect user data, and sell subscriptions, Chat402 offers:

* **True Privacy**: No accounts, no login, no tracking. Conversations stored only in your browser's localStorage.
* **Pay-Per-Use**: No subscriptions. Pay only for tokens consumed, starting at \$0.001 per message.
* **Multi-Model Access**: GPT-5.2, Claude Opus 4, GPT-4o, Gemini, Grok, DeepSeek - all in one place.
* **Crypto-Native**: USDC payments on Solana with sub-second settlement.

## Core Innovation: SPL Token Delegation

Chat402 uses Solana's SPL token delegation mechanism to enable signless payments:

1. User approves a one-time delegation of USDC to Chat402's delegate address
2. For each prompt, Chat402 automatically transfers the exact cost from user's wallet
3. No signature popups - just seamless conversation flow
4. User can revoke delegation at any time

This approach combines the user experience of subscriptions with the privacy and flexibility of pay-per-use.

## Pricing Model

Chat402 operates on a transparent 2x markup model:

| Model         | Chat402 Price     | Provider Cost |
| ------------- | ----------------- | ------------- |
| GPT-5.2       | \$0.023/1K tokens | \~\$0.012/1K  |
| Claude Opus 4 | \$0.090/1K tokens | \~\$0.045/1K  |
| GPT-4o        | \$0.005/1K tokens | \~\$0.003/1K  |
| DeepSeek Chat | \$0.001/1K tokens | \~\$0.0005/1K |

## Rate Limits

* **Per API Key**: 1,000 requests/minute
* **Per IP Address**: 200 requests/minute

These limits ensure fair usage while accommodating high-volume applications.

***

For the complete technical details, security analysis, and implementation specifics, [download the full whitepaper](https://www.chat402.xyz/whitepaper.pdf).