Imported from davepoon/buildwithclaude (plugins/all-skills/skills/hexanon-x402-apis/SKILL.md). Install upstream with npx skills add davepoon/buildwithclaude --skill hexanon-x402-apis. Copyright stays with the author.

Hexanon x402 APIs

Eight independently operated, pay-per-call HTTP APIs that an agent can call directly with USDC micropayments over x402 on Base — no accounts, no API keys. Probe any paid route unauthenticated to get a machine-readable HTTP 402 challenge, pay with an x402 client, and retry. Responses are only charged when the work succeeds (charged: true).

All endpoint guidance an agent needs is inlined below (snapshot: 2026-08-01). Each origin also publishes a machine-readable openapi.json as its reference spec if you need parameter details.

When to Use This Skill

• Vehicle / VIN due diligence for a US or Canada used car (decode, recalls, known issues, pre-purchase report) — Vindex, api.vindexapi.dev
• Finding market gaps and product-demand signals — what buyers want but can't find — Demandex, api.demandex.dev
• Polymarket intelligence: whale positioning, signals, resolving-soon markets, track records — OrcaTrace, api.orcatrace.dev
• Developer-ecosystem intelligence: trending GitHub repositories and momentum — gitBeacon, api.gitbeacon.dev
• Narrative and content intelligence: emerging narratives, pulse content, intelligence briefs — Signalis, api.signalis.dev
• Moltbook community intelligence: digests and a Viral Advisor that scores/rewrites posts — Moltalyzer, api.moltalyzer.xyz
• Checking whether an x402 API origin conforms to what x402scan, Bazaar and agent buyers require — x402lint, api.x402lint.dev
• Polymarket weather-market bucket-transition signals — Isocast, api.isocast.dev

Endpoints (snapshot 2026-08-01)

Every product exposes free sample/index routes, so an agent can preview response shapes before paying. Prices below are USDC on Base (eip155:8453); the live 402 challenge on each route is always the exact price at call time.

Vindex — vehicle & VIN intelligence (https://api.vindexapi.dev)

Demandex — e-commerce demand signals (https://api.demandex.dev)

OrcaTrace — Polymarket whale intelligence (https://api.orcatrace.dev)

gitBeacon — GitHub trending intelligence (https://api.gitbeacon.dev)

Signalis — narrative intelligence (https://api.signalis.dev)

Moltalyzer — Moltbook community intelligence (https://api.moltalyzer.xyz)

x402lint — x402 seller conformance (https://api.x402lint.dev)

Isocast — Polymarket weather-market signals (https://api.isocast.dev)

How Payment Works

1. Probe a paid route unauthenticated — the API answers HTTP 402 with an accepts block naming the exact price, asset (USDC), network (Base) and pay-to address.
2. Pay and retry using a pinned x402 client library in your own code, e.g. @x402/fetch (npm install @x402/fetch @x402/evm viem at a pinned version and wrap fetch with your wallet signer). Avoid piping URLs through unpinned, runtime-installed CLI tools.
3. Wallet setup is a human step: fund a Base (eip155:8453) wallet with USDC and provision its key to your agent before enabling paid calls. Free routes need no wallet.

Example

User: "Decode this VIN and tell me about recalls."

Output:

1. GET https://api.vindexapi.dev/v1/decode?vin=<VIN>  -> HTTP 402 challenge
2. Pay via x402 client (USDC on Base) and retry -> normalized NHTSA vPIC decode
3. GET https://api.vindexapi.dev/v1/recalls?vin=<VIN> -> merged US (NHTSA) + Canada recalls

Tips

• Try the free sample/index routes first to see response shapes before spending anything.
• Prices in this document are a reviewed snapshot; the 402 challenge on each route is always the exact, current price — your x402 client sees it before paying, so a stale snapshot can never overcharge you.
• Each origin's openapi.json is its machine-readable reference spec for parameters and response schemas.
• Conformance or directory listing does not imply endorsement. These are eight separate APIs under the Hexanon family (hexanon.dev).