x402lint — scan, check, improve, ship

Lint your x402 listing before agents skip it.

25 read-only checks against your live origin — the 402 handshake, your agent docs, your directory standing — return an A–F grade with per-check evidence and a one-line fix for each finding. SSL Labs, for x402 sellers.

https://

Free grade lookup and full report. An always-fresh scan is a paid x402 call — no signup, no keys here.

x402lint report

api.example.dev

B
SCORE82 / 100
PASS

19

WARN

4

FAIL

2

P5head-no-settle
S5bazaar-post-extensions
P2x402-challenge

sample report · your grade varies

// THE MARKET TRUTH

Most x402 listings are silently broken. Agents just move on.

~2,900

x402 origins registered

~127

made a sale last month

the rest

silently broken or invisible

There is no error message when an agent skips you — it just picks the next origin that answers the handshake cleanly. x402lint finds the exact reasons, before your buyers do:

P2Dead 402s — a paid route that never returns a valid x402 challenge.
P8Oversized CDP descriptions that get truncated or rejected on listing.
S5Missing Bazaar POST extensions, so paid POSTs never get discovered.
S3Free ops missing security: [], so x402scan mis-indexes them.
P5No-settle guard broken — a garbage payment header served a 200.
D1Not registered on x402scan at all, so no agent can find you.

// 25 CHECKS · v2026-07-25.1

What we check

Every check is read-only and versioned. We fetch your live surfaces — never send a real payment (the only payment-ish probe is a literal garbage header) — and grade three categories.

Protocol & payment surface

8 checks

402 challenge validity, accepts[] schema, price integrity, HEAD-does-not-settle, and payment-header correctness.

Discovery & agent docs

12 checks

OpenAPI x402 conventions, security schemes, Bazaar extensions, .well-known surfaces, llms.txt, agent-card, robots, and favicon.

Ecosystem standing

5 checks

Registration/freshness on x402scan, recent on-chain settlement, trust tier, and x402.org presence.

25 checks across 3 categories — the full per-check findings and fixes are free to read in the cached report; pay only to force an always-fresh re-scan.

// DIRECTORY

Previously scanned

The recently-scanned archive of graded origins (5159 total). Branding is auto-collected and unverified.

Grades measure x402 protocol conformance only — not legitimacy or safety. A well-built scam can score an A. Always do your own diligence before paying any service.

x402Orang Apes Mint

x402orangapes.vercel.app

F

Protocol 26·Docs 77·Standing 99

RE-ROLLED ORANG APES 🟧 EACH APE IS UNIQUE 🟧 NOT AFFILIATED WITH BAYC OF YUGA LABS 🟧🟧

on x402scan

x402 Leaderboard

leaderboard.0000402.xyz

B

Protocol 100·Docs 54·Standing 99

Pay to create or update public leaderboards through a single write endpoint. Public reads stay free and writes are gated by a secret leader…

on x402scan

Social Intel API

api.socialintel.dev

B

Protocol 86·Docs 63·Standing 99

Instagram influencer discovery API for AI agents. Search influencers by keyword, niche, country, city, demographics, or follower range. Ret…

on x402scan

x402 IPFS Pinning - Powered by openx402.ai

ipfs.openx402.ai

F

Protocol 5·Docs 74·Standing 99

on x402scan

OpenVPS — Servers that AI agents buy themselves

openvps.sh

F

Protocol 5·Docs 74·Standing 99

AI-agent VPS hosting. Pay USDC, get SSH in seconds. No signups, no API keys.

on x402scan

X4A • X402 USDC Paywall (Solana)

facilitator.x4a.app

F

Protocol 5·Docs 74·Standing 99

on x402scan

Frego x402 AI Shipping Agent

ship.frego.ai

F

Protocol 5·Docs 74·Standing 99

AI-powered shipping labels with crypto payments. Get instant shipping quotes from USPS, UPS, FedEx with natural language descriptions and x…

on x402scan

Grok Image Generation API

grok-image-api.natsukichan4.workers.dev

B

Protocol 90·Docs 64·Standing 99

AI image generation with fewest content restrictions. Pay-per-request via x402 micropayments, no API keys needed. USDC on Base.

on x402scan

vindex

api.vindexapi.dev

A

Protocol 90·Docs 100·Standing 99

Vehicle Intelligence for AI agents. Pay per call with x402 (USDC on Base) to decode any 17-char VIN with its original factory new-vehicle w…

✓ Verified owneron x402scan

Stablebase

stablebase.dev

F

Protocol 26·Docs 74·Standing 99

On-demand Postgres databases via Stablebase. Pay per request with x402 micropayments. No API keys needed.

on x402scan

AurelianFlo

aurelianflo.com

B

Protocol 90·Docs 79·Standing 99

AurelianFlo is a pay-per-call API for OFAC wallet screening, crypto wallet sanctions checks, exposure forecasts, review queue optimization,…

on x402scan

GEO x402 API

x402geo.com

B

Protocol 86·Docs 71·Standing 99

Paid GEO and SEO audit service with x402 payment-gated endpoints and ACP-compatible job tracking.

on x402scan

ATXP

hub.atxp.ai

B

Protocol 96·Docs 66·Standing 99

ATXP is the account for AI agents — identity, payments, communication, and tools in one platform. Fully compatible with x402 and MPP: ATXP-…

on x402scan

locally-merit-nest-specific.trycloudflare.com

locally-merit-nest-specific.trycloudflare.com

F

Protocol 5·Docs 74·Standing 99

on x402scan

SimpleFi — Simple Crypto Infrastructure

www.simplefi.tech

B

Protocol 90·Docs 74·Standing 99

SimpleFi builds simple, privacy-preserving tools that make crypto payments accessible to everyone.

on x402scan

x402-sentinel.fly.dev

x402-sentinel.fly.dev

B

Protocol 86·Docs 68·Standing 99

on x402scan

b3-marketplace-production.up.railway.app

b3-marketplace-production.up.railway.app

F

Protocol 26·Docs 77·Standing 99

on x402scan

egov-laws-data-api.kasanegi123.workers.dev

egov-laws-data-api.kasanegi123.workers.dev

F

Protocol 26·Docs 77·Standing 99

on x402scan

Fast Token

apitoken.clawwallet.cc

F

Protocol 5·Docs 74·Standing 99

Fast Token is an x402-powered prepaid API key gateway for OpenAI-compatible Azure inference endpoints.

on x402scan

lending-liquidation-sentinel

liquidation-sentinel.up.railway.app

F

Protocol 26·Docs 77·Standing 99

on x402scan

Safuclaw — Security Audit Skill for AI Agents

api.safuclaw.com

F

Protocol 26·Docs 77·Standing 99

Safuclaw is a security audit skill for AI agents. Scan any skill for malware, prompt injection, and data exfiltration.

on x402scan

x402.rye.com

x402.rye.com

F

Protocol 5·Docs 74·Standing 99

on x402scan

PreReason

api.prereason.com

B

Protocol 86·Docs 65·Standing 99

Financial market context for AI agents: macro, rates, bonds, FX, commodities, companies and Bitcoin. 33 briefings covering Treasury yields,…

on x402scan

$TUX402

xtux402.vercel.app

F

Protocol 26·Docs 77·Standing 99

A chain-agnostic protocol for web payments

on x402scan

Orcpin

orcpin.dev

B

Protocol 92·Docs 75·Standing 99

Agent-native x402 API: factual, block-anchored on-chain wallet and DeFi position snapshots on Base; x402 endpoint-reliability pre-flight ch…

on x402scan

auto-mint-delta.vercel.app

auto-mint-delta.vercel.app

F

Protocol 30·Docs 77·Standing 99

on x402scan

XFinance API · Docs

api.xfinance.cc

F

Protocol 26·Docs 77·Standing 99

on x402scan

Hyper Pay x402

hyperpay.fun

F

Protocol 5·Docs 74·Standing 99

the social way to pay.

on x402scan

Visionaire · Autonomous AI Being

visionaire.live

F

Protocol 26·Docs 78·Standing 99

An autonomous AI agent with persistent memory and daily contemplation. Born November 2024 on Solana.

on x402scan

Node4All Production API

api.node4all.com

B

Protocol 80·Docs 57·Standing 99

OpenAPI specification for Node4All production endpoints.

on x402scan

// PRICING

Grades are free. Fresh scans cost cents.

Look up any grade and read the full cached report for free. Force an always-fresh scan for a few cents in USDC over x402 — plus a machine tier for agents: bulk directory export and a change feed. No signup and no API keys.

Status lookup

FREE

no payment ever

Grade, score, and pass/warn/fail counts for any prior scan. The cold-email payload.

GET /v1/status

Cached full report

FREE

no payment ever

The complete per-check findings and fixes for any recently-scanned origin (<24h cache).

GET /v1/report

Change feed

$0.03

per call · USDC via x402

Machine tier: directory changes since a cursor — new, grade_changed, and rescanned events.

GET /v1/changes

Fresh conformance scan

main

$0.05

per call · USDC via x402

Force an always-fresh run of every check against your origin, bypassing the cache — A–F grade with per-check evidence and fixes.

POST /v1/scan

Directory export

$0.10

per call · USDC via x402

Machine tier: the full graded directory as one dump, with grade history per origin.

GET /v1/directory/export

// FOR AGENTS

Everything is machine-readable

Agents: start at llms.txt on the API host. No docs portal, no sandbox keys, no signup — the challenge tells you the price and where to pay. There is a machine tier too: a bulk directory export and a change feed for agents that track the graded directory.

llms.txtapi.x402lint.dev/llms.txtllms-full.txtapi.x402lint.dev/llms-full.txtopenapi.jsonapi.x402lint.dev/openapi.json.well-known/x402api.x402lint.dev/.well-known/x402.well-known/agent-card.jsonapi.x402lint.dev/.well-known/agent-card.jsondiscoveryapi.x402lint.dev/discovery