Built for agents, from first principles

Why x402 (vs. API keys + Stripe)

The 4-step flow, expanded

All four steps are HTTP. No SDK is required. The protocol is a 402 status code, two headers, and a JSON body. An end-to-end agent transaction looks like this:

GET https://www.supercomputing.news/.well-known/x402.json

GET /api/v1/articles/:slug

HTTP/1.1 402 Payment Required
PAYMENT-REQUIRED: true
X-Price: $0.03
WWW-Authenticate: x402

{
  "scheme": "exact",
  "network": "eip155:8453",
  "price": "$0.03",
  "payTo": "0x…",
  "resource": "https://www.supercomputing.news/api/v1/articles/:slug"
}

GET /api/v1/articles/:slug
X-PAYMENT: <base64-encoded signed payload>

HTTP/1.1 200 OK
PAYMENT-RESPONSE: <tx-hash + metadata>

{
  "slug": "…",
  "title": "…",
  "content": { … },
  "provenance": {
    "contentHash": "<sha256-hex>",
    "signature": "<base64 Ed25519>",
    "signingKeyId": "scn-2026-05",
    "signedAt": "2026-…",
    "publicKeyUrl": "https://www.supercomputing.news/.well-known/scn-pubkey.json"
  }
}

Pricing

All payments settle in USDC on Base. Prices below are authoritative, generated from the same PRICING constants the API enforces.

Cryptographic provenance

Every published article is signed at publication time with an Ed25519 keypair. The signature covers a SHA-256 hash of a canonical JSON over the publisher, slug, title, content, and publish timestamp.

• contentHash = SHA256(canonical({publisher, slug, title, content, publishedAt}))
• signature = Ed25519(`$${contentHash}|$${slug}|$${publishedAt}`)
• Public key is published at /.well-known/scn-pubkey.json in JWK form with a stable key ID.

Active signing key

Verify a signature (free)

The /api/v1/provenance/verify endpoint is public and unmetered. Pass ?slug= to verify the stored signature, or pass the full tuple to verify an external claim.

curl 'https://www.supercomputing.news/api/v1/provenance/verify?slug=YOUR-SLUG'

Why this matters: agents that cite Supercomputing News can prove the bytes they quoted are the bytes the publisher signed. Citations become falsifiable.

The machine-readable manifest

/llms.txt is the single discovery URL agents need. It lists the base API URL, free vs. paid endpoints with pricing, the verification endpoints, and the canonical onboarding URL (this page). The structured pricing manifest lives at /.well-known/x402.json.

Editorial principles for agent-citable journalism

Treating agents as a first-class audience is an editorial commitment, not just a technical one. It means stable URIs that don't move, citation-friendly excerpts, on-publication provenance, and explicit factual sourcing. Not every publisher will commit to this discipline. That's the point. Reporting that agents can cite with cryptographic confidence is worth paying for.

Compliance & terms

Agent access via x402 settlement is welcome and encouraged. Scraping paid endpoints without payment is not. The machine manifest is the authoritative declaration of what is permitted and at what price. See the terms of use for the full agreement.

Endpoint reference

Sourced from PRICING in the API codebase. These are the live values, not documentation drift.

Start building

The fastest path is to load the manifest, attempt a paid endpoint, and let the 402 response tell your client what to sign. Sample client and partner contact below.