Overview
The HTTP 402 Paywall Protocol is the technological foundation of 402Gate a system that revives the unused HTTP status code 402 Payment Required as a native crypto monetization layer for the Internet.
It enables any API, website, or digital service to charge users instantly and automatically for access, without the need for centralized accounts, recurring subscriptions, or manual billing.
When a client requests a paid resource, the server responds with:
HTTP/1.1 402 Payment Required :
along with payment details such as amount, wallet address, and token type (e.g., USDC, SOL).
Once the payment is made and verified on-chain, the client retries the same request this time receiving a 200 OK response with the requested data or content.
This architecture establishes a trustless, frictionless, and programmable pay-per-use ecosystem, perfectly aligned with the high throughput and low-cost environment of Solana.
Core Purpose
Transform the legacy web request cycle into a transaction-aware economic layer.
Provide developers with a drop-in paywall API for digital services and data endpoints.
Remove friction between content access and value exchange, allowing direct, micro-scale payments with no intermediaries.
Core Capabilities
Instant Crypto Monetization
Turn any REST API, file server, or web endpoint into a pay-per-use gateway.
The protocol responds dynamically to user requests, issuing automatic payment prompts and unlocking access within seconds once payment is confirmed.
No Accounts, No Subscriptions
Users don’t need to register or log in. Each interaction is stateless identity is verified through wallet signatures and on-chain proof of payment, not user credentials.
Programmable Access Rules
Developers can define access logic (pricing, tokens accepted, expiry duration, retry limit) directly in API metadata or smart-contract configs.
This allows customized monetization flows per request, per file, or per session.
Dynamic Pricing Engine
The protocol supports adaptive fee calculation based on demand, data size, or resource tier.
Example: API endpoints that fetch high-frequency data (like price feeds) can cost more per request, while cached or static content can cost less.
Pricing formulas can be bound to oracles or smart contracts to ensure fairness and transparency.
On-Chain Verification Layer
Each transaction proof (via Solana RPC or smart contract event) is validated automatically before delivering content.
This layer guarantees:
Exact amount = required price
Correct recipient
Valid memo / request ID
Single-use payment token
This eliminates fraud, spoofed headers, or replayed payments.
Developer Integration SDK
The 402 SDK provides a plug-and-play client library for integrating the protocol into apps and services:
fetchWith402() for browser or Node API calls
Middleware templates for Express, Fastify, or Next.js API Routes
Helper functions for Solana transaction verification
With the SDK, Web2 developers can adopt pay-per-use payments without touching smart-contract logic, bridging traditional apps with decentralized monetization.
Why It Matters
The HTTP 402 Paywall Protocol represents a new standard for digital value exchange a bridge between traditional web infrastructure and blockchain-based payments.
It’s lightweight, open, and interoperable giving developers and businesses the ability to monetize at any scale, from one-cent API calls to complex AI data feeds.
With 402Gate, the web evolves from “read and write” to “read, write, and pay” instantly, securely, and autonomously.
