x402 Service Discovery
Discover & rank x402 payment-gated APIs by capability, price & ERC-8004 trust. USDC on Base.
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x402 Service Discovery MCP Server
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The community-built Bazaar for the x402 agentic economy — a continuously growing catalog of live services with real-time quality signals, facilitator-compatibility checks, and ERC-8004 trust scoring. The discovery layer that Coinbase's own PROJECT-IDEAS.md asked the community to build.
ScoutGate — Instant x402 API Monetization
Wrap any existing API in x402 payments in under 2 minutes — no protocol knowledge required
The x402 ecosystem's biggest friction point has been supply-side: getting an API behind x402 payments requires understanding EIP-712 headers, facilitator registration, and settlement logic. ScoutGate removes all of it.
# Register your existing API (30 seconds)
curl -X POST https://x402-scoutgate.onrender.com/register \ -H "Content-Type: application/json" \ -d '{"api_url": "https://your-api.com", "wallet_address": "0xYourWallet", "price_usd": 0.01, "name": "My API"}'
# Returns: {"proxy_url": "https://x402-scoutgate.onrender.com/api/abc123", "api_id": "abc123"}
That's it. Your API is now x402-enabled, auto-listed in x402Scout, and settling on Base mainnet in real USDC. ScoutGate handles facilitator integration, EIP-712 verification, and settlement.
Fee model: 2% per transaction (min $0.002). Live at: https://x402-scoutgate.onrender.com | Register your API
Terminal CLI — x402scout
Search the full x402 service catalog from your terminal
# Install (npm)
npm install -g x402scout
# Search
x402scout search "weather data"
# Top services by trust score
x402scout top 10
# Browse by category
x402scout browse data
# Scan a URL for x402 compliance
x402scout scan https://api.yourservice.com
# Ecosystem stats
x402scout stats
See cli/README.md for full usage.
scout_relay — Autonomous Payment Router
Route, execute, and audit x402 payments in a single call
Where the Discovery MCP finds what to call, scout_relay handles calling it — discovering the best service, making the x402 payment, retrying on failure, and returning the result. One call. Fully autonomous.
# Route an intent to the best matching x402 service
curl -X POST https://x402-scout-relay.onrender.com/route \
-H "Content-Type: application/json" \
-H "X-Payment: <your-x402-payment-header>" \
-d '{"intent": "blockchain analytics for wallet 0xABC", "max_budget_usd": 0.05}'
4 MCP tools — add to any MCP client:
| Tool | What It Does |
|---|---|
scout_route | Discover best service for an intent + execute payment |
scout_discover | Query the discovery catalog without executing |
scout_execute | Execute payment to a known service URL |
scout_audit | View spend log and agent budget status |
Fee model: max($0.003, 2.5% of downstream transaction value) per routed call.
Placement bids: Providers can register routing priority bids at POST /placement/bid (x402-gated, $0.01 registration fee). Bids are used as tiebreakers after trust-score filtering — merit first, always.
| Endpoint | Description |
|---|---|
GET /health | Service health + version |
POST /route | Route an intent (x402-gated) |
POST /execute | Execute to a known URL (x402-gated) |
GET /discover | Catalog discovery (free) |
GET /audit | Spend log (free) |
POST /placement/bid | Register a provider placement bid (x402-gated, $0.01) |
GET /placement/bids | View all active placement bids (public) |
Live at: https://x402-scout-relay.onrender.com
What This Is (30 seconds)
x402 is Coinbase's HTTP-native micropayment standard for the agentic web. An AI agent hits an endpoint, gets an HTTP 402 challenge, pays with USDC on Base, and receives data — no API keys, no subscriptions, pure machine-to-machine.
The problem: Hundreds of x402-payable services exist across the ecosystem. The official x402.org catalog lists names. That's it. No uptime data. No latency scores. No facilitator-compatibility flags. No trust signals. An agent has no way to know which services are actually live, trustworthy, or compatible with its payment flow.
This MCP server solves it. Connect any Claude, Cursor, or Windsurf agent directly to the x402 Service Discovery API — a continuously-updated catalog with real quality signals on every entry. Find services, check health, verify facilitator compatibility, and register new endpoints — all from inside your AI workflow.
MCP Tools (5 discovery + 4 relay = 9 total)
Discovery Tools
| Tool | What It Does | Cost |
|---|---|---|
x402_discover | Semantic search across the live catalog by keyword, category, max price | $0.010 USDC (pays via x402) |
x402_health | Real-time uptime + latency check for any registered service | $0.001 USDC (pays via x402) |
x402_register | Register a new x402 service (HTTPS-only, rate-limited) | Free |
x402_attest | ERC-8004 trust score and reputation signals for a service | Free |
x402_scan | Full x402 compliance scan: live config, trust score, mismatch detection | $0.010 USDC (pays via x402) |
Relay Tools (via scout_relay)
| Tool | What It Does | Cost |
|---|---|---|
scout_route | Discover best service for an intent + execute x402 payment | max($0.003, 2.5%) |
scout_discover | Query discovery catalog without executing | Free |
scout_execute | Execute x402 payment to a known service URL | max($0.003, 2.5%) |
scout_audit | View agent spend log and budget status | Free |
Quickstart — 30 Seconds to Discovery
Option A: Docker (recommended)
Add to your claude_desktop_config.json, Cursor MCP settings, or Windsurf config:
{
"mcpServers": {
"x402-discovery": {
"command": "docker",
"args": ["run", "-i", "--rm", "ghcr.io/rplryan/x402-discovery-mcp:latest"]
}
}
}
Option B: npx (no Docker required)
{
"mcpServers": {
"x402-discovery": {
"command": "npx",
"args": ["-y", "@rplryan/x402-discovery-mcp"]
}
}
}
Option C: Direct API
The Discovery API is publicly accessible — no authentication required:
# Search for services
curl "https://x402scout.com/discover?query=blockchain+analytics&max_price_usd=0.01"
# Full catalog
curl "https://x402scout.com/.well-known/x402-discovery"
Why This Matters
The Discovery Gap in x402
The x402 protocol solves payment. It does not solve discovery. When hundreds of services exist but agents can't find, evaluate, or route to them intelligently, the protocol's full value is unrealized.
This project fills that gap with three layers:
- Discovery — Find x402 services by capability, category, price ceiling
- Quality signals — Uptime %, latency (ms), facilitator compatibility, ERC-8004 trust score
- Execution — scout_relay discovers, pays, retries, and returns results autonomously
What Makes This Different from x402.org/ecosystem
| Capability | x402.org/ecosystem | This Project |
|---|---|---|
| Service listings | ✅ Names + URLs | ✅ Full metadata |
| Uptime monitoring | ❌ None | ✅ Live health checks |
| Latency data | ❌ None | ✅ Per-service ms scores |
| Facilitator compatibility | ❌ None | ✅ Per-service flag |
| ERC-8004 trust signals | ❌ None | ✅ Reputation scoring |
| Agent-native usage prompts | ❌ None | ✅ llm_usage_prompt per service |
| Auto-updated catalog | ❌ Manual | ✅ Scans every 6 hours |
| MCP integration | ❌ None | ✅ 9 tools, registry-published |
| Semantic search | ❌ None | ✅ Keyword + category + price |
| Autonomous execution | ❌ None | ✅ scout_relay — discover + pay + retry |
| Agent integration hints | ❌ None | ✅ howToUse block per service — exact x402 payment steps |
Live Catalog Stats
Total Services: Live — check https://x402scout.com/catalog
Auto-scan interval: 6 hours
Scan sources: x402.org/ecosystem, awesome-x402, GitHub search
Categories: data, compute, agent, utility
Facilitator-compat: Flagged per service
Trust signals: ERC-8004 per service
Primary URL: https://x402scout.com
Trust scores: 0-100 per service (ERC-8004 based)
Payment metadata: x402Config (address, asset, version) per service
Router: Live at https://x402-scout-relay.onrender.com
Catalog Sample
| Category | Count | Notable Services |
|---|---|---|
| data | Live | CoinGecko, Einstein AI, DJD Agent Score, Ordiscan, Nansen, Zapper, AdEx AURA |
| utility | Live | dTelecom STT, Pinata, Tip.MD, Cybercentry, Trusta Attestation, AsterPay |
| compute | Live | BlockRun.AI, X402Engine, AurraCloud, AiMo, QuickSilver |
| agent | Live | Questflow, Ubounty, Bitte Protocol, Farnsworth, SerenaI |
Example: Agent Workflow
Discovery only
# 1. Agent needs blockchain analytics under $0.01
result = x402_discover(
query="blockchain analytics whale tracking",
max_price_usd=0.01,
category="data"
)
# Returns: ranked list with price, uptime %, latency, llm_usage_prompt
# 2. Scan for compliance + trust before paying
scan = x402_scan(url=result[0]["url"])
# 3. Check live health before committing
health = x402_health(url=result[0]["url"])
Full autonomous execution via scout_relay
# One call — discovery + payment + retry handled automatically
result = scout_route(
intent="blockchain analytics for wallet 0xABC",
max_budget_usd=0.05
)
# Returns: {result: {...}, provider: "...", fee_usd: 0.003, trust_score: 82}
Payments use EIP-712 signed TransferWithAuthorization via the x402 HTTP protocol — not direct ERC-20 transfer. Signature verified server-side; on-chain settlement via receiveWithAuthorization.
CDP Builder Grant Context
This project is a direct implementation of two items from Coinbase's own public roadmap:
From PROJECT-IDEAS.md in coinbase/x402:
"Dynamic Endpoint Shopper — An agent that discovers an MCP registry, pays for access, chains results from multiple services"
From the CDP x402 facilitator roadmap:
"A discovery layer for buyers (human and agents) to find available services (Bazaar)"
We built the community Bazaar. It's live. It has quality signals the official page doesn't. And it uses x402 payments itself — x402_discover costs $0.010 USDC, paid via the protocol it serves. scout_relay extends this: it routes and executes x402 payments autonomously, charging its own x402 fee for the service.
What We've Shipped (11 days)
| Deliverable | Status |
|---|---|
| x402 Service Discovery API v3.7.0 | ✅ Live on Render |
| x402 Discovery MCP Server | ✅ Docker + GitHub MCP Registry |
| x402 RouteNet v1.0.0 (smart routing) | ✅ Live on Render |
| x402 Payment Harness v1.0.0 (EOA testing) | ✅ PyPI pip install x402-payment-harness |
| Continuously growing catalog with quality signals | ✅ Auto-updating every 6h |
| ERC-8004 trust layer | ✅ Per-service trust scoring |
| Facilitator compatibility layer | ✅ Pre-payment compatibility check |
| Full HTTP 402 protocol flow proven on Base | ✅ EIP-712 sign → X-PAYMENT header → 200 |
| x402scout CLI v1.0.0 | ✅ npm install -g x402scout |
| scout_relay v2.1.0 (payment router) | ✅ Live on Render |
| Provider placement bids (POST /placement/bid) | ✅ Live — x402-gated, self-serve |
| x402Config payment metadata in catalog | ✅ payment_address, asset_contract, x402Version per service |
/scan compliance endpoint (paid) | ✅ Live — compliance grade, mismatch detection, trust score |
howToUse integration blocks | ✅ Per-service exact x402 payment steps in /discover results |
| Landing page (x402scout.com) | ✅ NVG green design, live stats, code snippets |
| Endpoint security hardening | ✅ SSRF guard, rate limiting, HTTPS-only on /register |
| Smithery score | ✅ 100/100 |
| GitHub MCP Registry | ✅ Published: io.github.rplryan/x402-discovery-mcp |
| ScoutGate v1.0.0 (x402 API monetization gateway) | ✅ Live on Render — wrap any API in x402 payments in 30 seconds |
Architecture
┌─────────────────────────────────────────────────────┐
│ AI Agent (Claude / Cursor / Windsurf) │
│ │
│ x402_discover → x402_health → x402_attest │
│ x402_scan → x402_register → x402_health │
│ │
│ scout_route → scout_execute → scout_audit │
└──────────┬──────────────────────────┬───────────────┘
│ MCP (stdio/Docker) │ REST / MCP
┌──────────▼──────────┐ ┌──────────▼──────────────┐
│ x402 Discovery │ │ scout_relay v2.1.0 │
│ MCP Server │ │ x402-scout-relay │
│ ghcr.io/rplryan/ │ │ .onrender.com │
│ x402-discovery-mcp │ │ Fee: max($0.003, 2.5%) │
└──────────┬──────────┘ └──────────┬───────────────┘
│ HTTPS │ HTTPS
└──────────────┬───────────┘
│
┌─────────────────────────▼───────────────────────────┐
│ x402 Discovery API (Render, v3.7.0) │
│ https://x402scout.com │
│ │
│ • Growing catalog • Auto-scan every 6h │
│ • Health checks • Facilitator compat flags │
│ • ERC-8004 trust • llm_usage_prompt per service │
└─────────────────────────────────────────────────────┘
Related Projects
| Project | Description | Status |
|---|---|---|
| x402 Discovery API | REST backend powering this MCP server | Live v3.7.0 |
| scout_relay | Autonomous x402 payment router — discover + execute + audit in one call | Live v2.1.0 |
| x402 RouteNet | Smart routing across discovered services | Live v1.0.0 |
| x402 Payment Harness | EOA-based Python library + CLI for x402 payment testing | PyPI v1.0.0 |
| ScoutGate | Wrap any existing API in x402 payments in 30 seconds — no protocol knowledge required | Live v1.0.0 |
Register Your Service
If you're building an x402-enabled service, add it to the catalog:
curl -X POST https://x402scout.com/register \
-H "Content-Type: application/json" \
-d '{
"name": "My Service",
"url": "https://myservice.example.com/api",
"price_usd": 0.010,
"category": "data",
"description": "What your service does",
"network": "base-mainnet"
}'
Or use the x402_register MCP tool from inside Claude/Cursor/Windsurf.
Want routing priority? Register a placement bid at POST https://x402-scout-relay.onrender.com/placement/bid (x402-gated, $0.01 registration fee). Your service gets weighted as a tiebreaker after trust-score filtering — merit first, always.
License
MIT
Built on Coinbase x402 protocol | Base Network | ERC-8004 | Model Context Protocol