> ## Documentation Index
> Fetch the complete documentation index at: https://shinydapps-bd9fa40b.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# White Paper — Extended Edition

> The complete technical specification of l402-kit. 100 sats. Served by l402-kit itself.

# White Paper — Extended Edition

**Version 1.1 — May 2026 · \~25 pages**

*Payment is the credential.*

***

This is the complete technical specification of l402-kit — the founding principles in full, design decisions with tradeoffs, expanded threat model, architectural properties, L402 vs x402 comparison, and versioning commitments.

The document is served by l402-kit itself. Paying 100 sats is an end-to-end test of the protocol in production.

***

## What's inside

| Section                           | Contents                                                                       |
| --------------------------------- | ------------------------------------------------------------------------------ |
| **Preface**                       | Author's note — why this was built                                             |
| **§1 Founding Principles**        | All 7 principles in full (80–120 words each)                                   |
| **§2 The Problem**                | HTTP was built for humans — 25 years of dormancy                               |
| **§3 Protocol in 5 Minutes**      | Four-step sequence, token format, three properties                             |
| **§4 Architecture**               | Two modes, replay protection layers, agent discovery                           |
| **§5 Design Decisions**           | Why 4 languages, why Blink, why MIT, what's excluded                           |
| **§6 Threat Model**               | Full table: 11 threats, mitigations, responsibilities                          |
| **§7 Architectural Properties**   | Invariants: constant-time, horizontal scale, memory                            |
| **§8 Use Cases**                  | Pay-per-call, AI agents, content gating                                        |
| **§8.1 Autonomous Agent Economy** | The complete loop: earn → accumulate → spend → reputation — zero human capital |
| **§9 L402 vs x402**               | Honest comparison table — including where x402 is better                       |
| **§10 Economic Model**            | 0.3% fee, Pro, Founder — with reasoning                                        |
| **§11 Versioning**                | Patch/minor/major commitments, wire format stability                           |
| **Appendix A**                    | Glossary — 7 terms                                                             |
| **Appendix B**                    | References — 6 sources                                                         |
| **Appendix C**                    | Document changelog — v1.0 → v1.1                                               |
| **Appendix D**                    | Design notes: Macaroons vs JWT, Blink, 0.3%, stateless                         |

***

## Pay and read

```bash theme={null}
# Step 1 — Request the document (get invoice)
curl -i https://l402kit.com/whitepaper-extended

# HTTP/1.1 402 Payment Required
# WWW-Authenticate: L402 macaroon="<macaroon>", invoice="lnbc..."
# {"priceSats":100,"invoice":"lnbc...","macaroon":"<macaroon>"}

# Step 2 — Pay the invoice with any Lightning wallet
# Get the preimage from your wallet after payment

# Step 3 — Access the document
curl -H "Authorization: L402 <macaroon>:<preimage>" \
     -H "Accept: text/html" \
     https://l402kit.com/whitepaper-extended \
     -o whitepaper-extended.html

# Open whitepaper-extended.html in your browser → File → Print → Save as PDF
```

***

## One-liner with l402-kit client

```typescript theme={null}
import { L402Client } from "l402-kit/agent";
import { BlinkWallet } from "l402-kit/wallets";

const client = new L402Client({
  wallet: new BlinkWallet(process.env.BLINK_API_KEY!),
  budget: { maxSats: 200 },
});

const html = await client.fetch("https://l402kit.com/whitepaper-extended", {
  headers: { Accept: "text/html" },
});
// Paid automatically. html is the complete document.
```

***

## Price

**100 sats** (approximately the cost of an SMS, in any country).

The public version — abstract, architecture, quickstart, and seven principles in brief — is free at [docs.l402kit.com/whitepaper](/whitepaper).

<Note>
  This endpoint is served by l402-kit itself using the ManagedProvider. When you pay, the split runs automatically: 99.7 sats to ShinyDapps, 0.3 sats as protocol fee. The entire flow — invoice creation, payment, verification, document delivery — runs without human intervention.
</Note>