What is Preimage Research?

Preimage Research is payment infrastructure for machine-to-machine commerce. It enables APIs to accept USDC micropayments using the x402 protocol (HTTP 402 + blockchain payments).

The Problem

Traditional API monetization requires:

Complex authentication systems
Subscription management
Payment processing (credit cards, invoices)
Usage tracking and billing
Customer account management

This creates significant overhead for API providers and friction for API consumers.

The Solution

With Preimage Research:

API Providers add one line of middleware
API Consumers use a simple client library
Payments happen automatically via USDC on Base/Ethereum/Polygon
No subscriptions, no accounts - just pay-per-use

✓

Pay-per-call pricing: Charge $0.001 per API call, $0.01 per LLM token, or $0.05 per compute second. Payments as granular as 1/1,000,000th of a USDC (6 decimals).

Key Features

x402 Protocol

Preimage Research implements the x402 protocol, a standard for HTTP payments developed by Coinbase:

402 Payment Required HTTP status code
Challenge-response pattern for authentication
EIP-3009 USDC transfers with authorization
Macaroons for time-limited access tokens
JWS receipts for verifiable proof of payment

Non-Custodial

You control your wallet. Payments go directly to your address. Preimage Research never holds funds.

┌──────────────┐         ┌──────────────┐
│   Buyer      │ ──USDC─→│   Provider   │  (98%)
│   Wallet     │         │   Wallet     │
└──────────────┘    ↓    └──────────────┘
                    │
                    └───→ Preimage Research (2%)

Dual Invoice Architecture

Every payment is split automatically:

98% to the API provider
2% to Preimage Research platform

Both payments happen atomically in a single blockchain transaction.

Verifiable Receipts

Every API call that involves payment generates a cryptographically signed receipt:

{
  "paymentId": "pay_abc123",
  "providerId": "prov_xyz789",
  "endpointId": "ep_weather",
  "totalUsdc": "1000",
  "providerUsdc": "980",
  "platformUsdc": "20",
  "timestamp": "2024-01-15T10:30:00Z",
  "signature": "eyJhbGciOiJFUzI1NiJ9..."
}

These receipts are:

Signed with JWS (JSON Web Signature)
Verifiable by anyone with the public key
Immutable proof of payment
Finance-ready for accounting and compliance

💡

Receipts are returned in the Preimage-Receipt HTTP header on successful requests. Store them for auditing and reconciliation.

Supported Languages

Preimage Research provides 6 production-ready SDKs:

Client SDK (Buyer Side)

TypeScript - @preimage/client

Provider SDKs (Seller Side)

Express (Node.js) - @preimage/express
FastAPI (Python) - preimage-fastapi
Django (Python) - preimage-django
Gin (Go) - github.com/preimage-labs/preimage-go-gin
Axum (Rust) - preimage-axum

All SDKs implement the same x402 protocol and work seamlessly together.

Use Cases

AI API Monetization

Charge per token for LLM inference:

pricing: {
  usdcPerUnit: 0.00001,  // $0.00001 per token
  unitKind: 'token'
}

Data APIs

Charge per request:

pricing: {
  usdcPerUnit: 0.001,  // $0.001 per request
  unitKind: 'operation'
}

Compute APIs

Charge per second of compute:

pricing: {
  usdcPerUnit: 0.05,  // $0.05 per second
  unitKind: 'second'
}

Content APIs

Charge per article, video, or file:

pricing: {
  usdcPerUnit: 0.10,  // $0.10 per article
  unitKind: 'operation'
}

How Much Does It Cost?

For API Providers

Preimage uses 4-tier dynamic pricing that's 50-95% cheaper than traditional processors:

Payment Amount	Preimage Fee	Stripe Fee	You Save
$0.10 (micro)	$0.005 (5%)	Can't process	Only option!
$1.00	$0.08 (8%)	$0.329 (33%)	76% cheaper
$5.00	$0.20 (4%)	$0.445 (9%)	55% cheaper
$50.00	$1.30 (2.6%)	$1.745 (3.5%)	26% cheaper