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Marketplace MCP for paid HTTP APIs. Pay per call in USDC on Base via the open x402 standard — non-custodial. 13 tools for discovery, buying, and publishing APIs
Marketplace MCP for paid HTTP APIs. Pay per call in USDC on Base via the open x402 standard — non-custodial. 13 tools for discovery, buying, and publishing APIs.
npm version npm downloads bundle size License: MIT CI MCP Registry Base
Give your AI agent a wallet and a marketplace.
@gatefare/mcpis a Model Context Protocol server that connects Claude Desktop, Cursor, or any MCP-compatible agent to the Gatefare catalog of paid HTTP APIs. Payments settle as USDC on Base via the open x402 standard — no SaaS keys, no subscriptions, no escrow. Non-custodial: signing happens locally; the private key never leaves your machine.

┌─────────────┐ ┌──────────────┐ ┌─────────────────┐
│ Claude / │ MCP stdio │ @gatefare/mcp│ HTTP + x402 │ gatefare.io │
│ Cursor / │ ─────────────► │ (this repo)│ ─────────────► │ proxy + │
│ your agent │ │ │ │ catalog │
└─────────────┘ └──────┬───────┘ └─────────────────┘
│
│ EIP-3009 sign
▼
┌─────────────┐
│ Base USDC │
└─────────────┘
Claude Desktop — ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):
{
"mcpServers": {
"gatefare": {
"command": "npx",
"args": ["-y", "@gatefare/mcp"]
}
}
}
Cursor — ~/.cursor/mcp.json or project-level .cursor/mcp.json:
{
"mcpServers": {
"gatefare": {
"command": "npx",
"args": ["-y", "@gatefare/mcp"]
}
}
}
Restart the client. The agent now has 5 read-only tools — discovery + safety. Try:
"Search Gatefare for weather APIs."
Add env to the same config:
{
"mcpServers": {
"gatefare": {
"command": "npx",
"args": ["-y", "@gatefare/mcp"],
"env": {
"WALLET_PRIVATE_KEY": "0xYOUR_KEY",
"WALLET_BUDGET_USD": "5.00"
}
}
}
}
Buyer tools (call_api, get_wallet_balance, estimate_cost) become available. The
WALLET_BUDGET_USD cap is a runtime safety net — for a hard cap, fund the wallet with
only what you're willing to spend.
"What's London's weather right now? Spend up to $0.001."
Get a PAT at gatefare.io/dashboard/tokens and add:
"env": {
"GATEFARE_PAT": "gfpat_..."
}
Publisher tools (register_api, list_my_apis, update_api, get_revenue,
distribute) appear.
"Publish my API at https://api.example.com/sentiment for $0.001 per call."
13 tools across 4 domains. Tools auto-register based on which env vars are set — the agent never sees a tool it can't use.
| Tool | Description |
|---|---|
gatefare.search_apis |
Full-text search the catalog with filters (price, category, sort) |
gatefare.get_api |
Full details for one API by slug or handle/urlName |
gatefare.list_categories |
All categories with API counts |
gatefare.suggest |
Autocomplete suggestions for a query string |
WALLET_PRIVATE_KEY| Tool | Description |
|---|---|
gatefare.call_api |
Make a paid call. Handles 402 → sign → retry automatically |
gatefare.get_wallet_balance |
USDC + ETH on Base, plus remaining runtime budget |
gatefare.estimate_cost |
Project total cost for N planned calls |
GATEFARE_PAT| Tool | Description |
|---|---|
gatefare.register_api |
Publish a new paid API |
gatefare.list_my_apis |
Your published APIs with stats |
gatefare.update_api |
Edit metadata, price, target URL |
gatefare.get_revenue |
Revenue time series + totals |
gatefare.distribute |
Trigger on-chain distribute() payout (destructive) |
| Tool | Description |
|---|---|
gatefare.report_abuse |
Report a malicious / stolen API (DMCA, fraud, malware…) |
| Var | Default | Required for |
|---|---|---|
GATEFARE_BASE_URL |
https://gatefare.io |
— (override for self-hosted) |
WALLET_PRIVATE_KEY |
— | Any buyer tool |
WALLET_BUDGET_USD |
unlimited | Optional spend cap |
WALLET_NETWORK |
eip155:8453 |
eip155:84532 for Sepolia testnet |
GATEFARE_PAT |
— | Any publisher tool |
LOG_LEVEL |
info |
debug for verbose stderr |
You: Find me a sub-$0.001 weather API and call it for "Tokyo".
Claude: Calling
gatefare.search_apiswithmax_price: 0.001…
Founddemo-weatherby @alice at $0.001/call.
Callinggatefare.call_apiwithslug: "demo-weather",query: {city: "Tokyo"}…
Tokyo is 22°C, partly cloudy. Paid 0.001 USDC. Receipt:settled-tx-0x9a…
from mcp import ClientSession, StdioServerParameters
from mcp.client.stdio import stdio_client
server = StdioServerParameters(
command="npx",
args=["-y", "@gatefare/mcp"],
env={"WALLET_PRIVATE_KEY": "0x...", "WALLET_BUDGET_USD": "1.00"},
)
async with stdio_client(server) as (r, w):
async with ClientSession(r, w) as s:
await s.initialize()
result = await s.call_tool(
"gatefare.call_api",
arguments={"slug": "demo-weather", "query": {"city": "Tokyo"}},
)
print(result.content[0].text)
See examples/ for runnable variants: Claude Desktop, Cursor, Python, TypeScript, and a pure-discovery walkthrough.
If you want to pay for x402 APIs from a backend (no agent), use Coinbase's
official x402 SDKs — x402-python (PyPI), coinbase/x402/go, …/java, or
@x402/fetch. They handle the
payment flow; you don't need this MCP server.
If you want to browse the Gatefare catalog from any language, hit the REST API directly: gatefare.io/api/catalog (OpenAPI 3.1 spec).
Full breakdown of which tool fits which use case in docs/integrations.md.
# Run the server in foreground; talks JSON-RPC over stdio.
npx -y @gatefare/mcp
# In another terminal, send a frame:
echo '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}' | \
npx -y @gatefare/mcp
Tool results include isError: true and a structured body
{ error: <code>, message: <human>, details?: <any> }. Codes are stable —
agents can switch on them for retry / surfacing logic.
| Code | Meaning |
|---|---|
INVALID_INPUT |
Input failed zod validation |
WALLET_NOT_CONFIGURED |
Set WALLET_PRIVATE_KEY for buyer tools |
PAT_NOT_CONFIGURED |
Set GATEFARE_PAT for publisher tools |
BUDGET_EXHAUSTED |
Runtime budget cap hit |
INSUFFICIENT_BALANCE |
Wallet doesn't have enough USDC |
PRICE_TOO_HIGH |
Server's price exceeds your max_price |
API_NOT_FOUND |
Slug doesn't exist or is suspended |
UPSTREAM_ERROR |
Paid API returned non-2xx, or its 402 was malformed |
RATE_LIMITED |
Gatefare rate-limited the request |
NETWORK_ERROR |
Could not reach Gatefare |
GATEFARE_API_ERROR |
Gatefare returned a 4xx / 5xx |
gatefare.call_api { slug: "demo-weather", … }.GET https://gatefare.io/p/demo-weather (no payment yet).accepts: [{network, payTo, maxAmountRequired, …}].X-Payment header (base64-encoded JSON, x402 v2).The signature is single-use, time-bounded, and never leaves your machine for any
purpose other than this exact transfer to this exact payTo. The private key
is never logged.
Date.now()-based collisions.^[a-z0-9_-]+$ and URL-encoded;
no path traversal. targetUrl blocks file://, localhost, cloud
metadata IPs, .local, and .internal hosts at registration time.git clone https://github.com/gatefareio/mcp-server.git
cd mcp-server
npm install
npm run typecheck
npm test # 138 unit tests
npm run test:e2e # 10 e2e tests against live gatefare.io (set GATEFARE_E2E=1)
npm run build
To use a local checkout in your client config:
npm link
# in claude_desktop_config.json:
# "command": "gatefare-mcp"
src/
├── index.ts # entry — wires stdio transport
├── server.ts # McpServer instance + tool registration
├── config.ts # env parsing, capability detection
├── client.ts # REST client (wraps fetch)
├── x402.ts # 402 parsing + EIP-3009 signing
├── types.ts # shared types + GatefareError
└── tools/
├── discovery.ts # search_apis, get_api, list_categories, suggest
├── buyer.ts # call_api, get_wallet_balance, estimate_cost
├── publisher.ts # register_api, list_my_apis, update_api, get_revenue, distribute
└── safety.ts # report_abuse
tests/
├── config.test.ts # env parsing edges
├── client.test.ts # HTTP client error mapping
├── x402.test.ts # signing + parsing primitives
├── x402-flow.test.ts # full 402 → sign → retry handshake (mocked fetch)
├── server.test.ts # capability-driven tool registration
├── init.test.ts # subprocess: bootstrap, env crashes, secret leakage
├── stdio-protocol.test.ts # stdout pollution + recovery from tool errors
├── stability.test.ts # 100 concurrent calls, memory baseline, ReDoS
├── tools/
│ ├── discovery.test.ts
│ ├── buyer.test.ts
│ ├── buyer-flow.test.ts
│ ├── publisher.test.ts
│ └── safety.test.ts
└── integration/
└── e2e.test.ts # real gatefare.io, gated by GATEFARE_E2E=1
Issues and PRs welcome. See CONTRIBUTING.md for the workflow, style guide, and how to add a new tool.
MIT © Gatefare
Добавь это в claude_desktop_config.json и перезапусти Claude Desktop.
{
"mcpServers": {
"gatefareio-mcp-server": {
"command": "npx",
"args": []
}
}
}