Documentation

Call it like it is already yours.

The specification is public and machine-readable, the catalogue is live, and the free verification routes need no credential of any kind. The only thing that ever asks to be paid is a pay-per-call call — and it states its price in the response.

01Start here

Three calls and you understand it.

Base URL https://x402.synthexforge.com. Everything below is reachable right now — the free routes answer immediately and the pay-per-call ones answer 402 with their terms.

# the contract
curl -s https://x402.synthexforge.com/openapi.json | head

# a free route — no key, no payment
curl -s https://x402.synthexforge.com/health

# a pay-per-call route — answers 402 with the terms
curl -s -X POST https://x402.synthexforge.com/v1/receipts/mint \
  -H 'content-type: application/json' \
  -d '{}'

# 402 carries scheme, network, asset, amount and payTo.
# Sign an EIP-3009 authorisation and retry with it.

Catalogue captured 06 Oct 2026. Prices are per request and settle in USDC on Base mainnet.

02Endpoint reference

Every pay-per-call route, priced.

40 routes across 7 families, from $0.02–$29.00 per request. Select any route to see its method, family, price and the exact 402 contract it returns before you pay.

Priced catalogue · 40 pay-per-call routes
Endpoint
POST /v1/mcp/threatmodel/tool-permission
Family
Agent Infrastructure
Price
$0.25 USDC
Settlement
Base mainnet

402 response contract

HTTP/1.1 402 Payment Required

{
  "x402Version": 2,
  "resource": {
    "url": "https://x402.synthexforge.com/v1/mcp/threatmodel/tool-permission",
    "description": "Tool Permission Threatmodel",
    "mimeType": "application/json"
  },
  "accepts": [
    {
      "scheme": "exact",
      "network": "eip155:8453",
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "amount": "250000",
      "payTo": "0xc8fF67FAE72596478599EAAcfad8656fAe1113c8",
      "maxTimeoutSeconds": 60,
      "extra": {
        "name": "USD Coin",
        "version": "2",
        "assetTransferMethod": "eip3009"
      }
    }
  ]
}

Contract shape derived from the live settlement parameters. An unpaid request to this route returns 402 with these fields — the price is in the response.

03The surface

What is published, counted.

101Total routes
40Pay-per-call
61Free
7Families
17Verify routes
22Public keys

Counted from the live specification, not from a roadmap. Receive address 0xc8fF67FAE72596478599EAAcfad8656fAe1113c8 · exact on Base mainnet.

04Verification

Check us without paying us.

Every family that issues an attestation publishes a free verification route and a public key. A third party — a counterparty, a regulator, another agent — can confirm a claim without a credential, without a fee and without contacting us.

Governance/v1/bureau/anchor/verify/v1/bureau/verify/v1/governance/verify
Trust & Reputation/v1/agent-reputation/trusted-route/verify/v1/agent-reputation/verify/v1/identity/control-proof/verify/v1/readiness/attest/verify/v1/receipts/verify/v1/veritrack/verify
Forensics & Evidence/v1/data/verify/v1/evidence/verify
Security & Compliance/v1/compliance/verify/v1/containment/verify
Agent Infrastructure/v1/mcp/eval/judge/verify/v1/memory/verify
Documents & Data/v1/utils/verify
Research & Synthesis/v1/synthesis/verify

Public keys are published alongside these routes. Verification is free by design: a claim nobody can check is not worth much.