X402 API

Name: X402 API
Author: fernsugi

by fernsugiversion 1.0.5i★ –iRuns on your computer

Registry nameio.github.fernsugi/x402-api

Install

Overview

Description from the maker (original English)

Eight paid DeFi tools: prices, gas, swaps, token security, holders, yields, funding and wallets

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Other
You need to fill in: X402_WALLET_PRIVATE_KEY

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: X402_API_BASE_URL, X402_WALLET_PRIVATE_KEY, X402_MAX_PER_CALL_USDC, X402_REFERRAL_SOURCE, X402_EXPECTED_PAY_TO

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "x402-api": {
      "command": "npx",
      "args": [
        "-y",
        "@x402-api/mcp-server"
      ],
      "env": {
        "X402_API_BASE_URL": "your-value",
        "X402_WALLET_PRIVATE_KEY": "your-value",
        "X402_MAX_PER_CALL_USDC": "your-value",
        "X402_REFERRAL_SOURCE": "your-value",
        "X402_EXPECTED_PAY_TO": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add x402-api --env X402_API_BASE_URL=your-value --env X402_WALLET_PRIVATE_KEY=your-value --env X402_MAX_PER_CALL_USDC=your-value --env X402_REFERRAL_SOURCE=your-value --env X402_EXPECTED_PAY_TO=your-value -- npx -y @x402-api/mcp-server

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "x402-api": {
      "command": "npx",
      "args": [
        "-y",
        "@x402-api/mcp-server"
      ],
      "env": {
        "X402_API_BASE_URL": "your-value",
        "X402_WALLET_PRIVATE_KEY": "your-value",
        "X402_MAX_PER_CALL_USDC": "your-value",
        "X402_REFERRAL_SOURCE": "your-value",
        "X402_EXPECTED_PAY_TO": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "x402-api": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@x402-api/mcp-server"
      ],
      "env": {
        "X402_API_BASE_URL": "your-value",
        "X402_WALLET_PRIVATE_KEY": "your-value",
        "X402_MAX_PER_CALL_USDC": "your-value",
        "X402_REFERRAL_SOURCE": "your-value",
        "X402_EXPECTED_PAY_TO": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

X402_API_BASE_URL env
x402 API base URL (default: https://x402-api.fly.dev)
X402_WALLET_PRIVATE_KEY secret env
Base wallet private key for optional EIP-3009 auto-pay. Default mode inspects payment requirements without paying.
X402_MAX_PER_CALL_USDC env
Maximum USDC allowed per automatic tool call (default: 0.01)
X402_REFERRAL_SOURCE env
Optional referral label: github, glama, nohumans, bazaar, mcp, eliza, demo or test. Default mcp.
X402_EXPECTED_PAY_TO env
Expected payment recipient; defaults to the official x402-api wallet. Change only when using a trusted alternative deployment.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 6, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account fernsugi, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Otheri

More stars than 0% of the other 32466 servers in this category
Published to the registry more recently than 52% of the other 32466 servers in this category
Basic checks equal to or better than 100% of the other 32466 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is X402 API safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: X402_WALLET_PRIVATE_KEY

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (1.0.5) reached the registry 37 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, HotCodePush

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

@x402-api/mcp-server

MCP server that gives Claude, ChatGPT, and any MCP-compatible AI agent access to pay-per-call crypto/DeFi data via the x402 protocol.

8 tools. No API keys. AI agents pay USDC micropayments on Base, per request.

Find this service: Official MCP Registry · Glama · Agent discovery manifest · OpenAPI.

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Tools

Tool	API Endpoint	Cost	Description
`get_crypto_prices`	`GET /api/price-feed`	0.001 USDC	BTC/ETH/SOL + top 24h movers
`get_gas_prices`	`GET /api/gas-tracker`	0.001 USDC	Multi-chain gas (ETH, Base, Polygon, Arbitrum)
`get_dex_quotes`	`GET /api/dex-quotes`	0.002 USDC	One ParaSwap aggregate route
`scan_token`	`GET /api/token-scanner`	0.003 USDC	GoPlus security flags and heuristic
`track_whales`	`GET /api/whale-tracker`	0.005 USDC	Top-holder sample and supply share
`scan_yields`	`GET /api/yield-scanner`	0.005 USDC	DefiLlama pool APYs and TVL
`get_funding_rates`	`GET /api/funding-rates`	0.008 USDC	Hyperliquid and dYdX hourly rates
`profile_wallet`	`GET /api/wallet-profiler`	0.008 USDC	Observed Blockscout balances; partial coverage

Quick Start

Option A: Inspect mode (no payment needed)

Just run it — any 402 responses will return human-readable payment instructions:

npx @x402-api/mcp-server

Claude will tell you what's needed when a tool requires payment.

Option B: Auto-pay mode (fully autonomous)

Install optional payment deps and set your wallet key:

npm install -g @x402-api/mcp-server

npm install -g viem export X402_WALLET_PRIVATE_KEY=0x x402-api-mcp

The MCP server signs Base USDC EIP-3009 authorizations only when the API advertises that settlement mode. The default payment cap is 0.01 USDC per call. Fund the wallet with USDC on Base; the API operator sponsors gas in direct settlement mode.

Claude Desktop Integration

Add to your claude_desktop_config.json:

Without auto-pay (inspect mode)

"mcpServers": { "x402-api": { "command": "npx", "args": ["@x402-api/mcp-server"] } } }

With auto-pay

"mcpServers": { "x402-api": { "command": "npx", "args": ["@x402-api/mcp-server"], "env": { "X402_WALLET_PRIVATE_KEY": "0x " } } } }

Config file location:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json
Linux: ~/.config/Claude/claude_desktop_config.json

Environment Variables

Variable	Required	Description
`X402_WALLET_PRIVATE_KEY`	Optional	Base wallet private key for EIP-3009 automatic payment. Requires `viem`.
`X402_MAX_PER_CALL_USDC`	Optional	Per-call cap, default `0.01` USDC.
`X402_API_BASE_URL`	Optional	Override API URL (default: `https://x402-api.fly.dev`)

How x402 Payments Work

This API uses the x402 protocol — HTTP 402 Payment Required:

Agent calls tool → MCP server makes API request
Server returns 402 with payment details (amount, USDC address, Base network)
Auto-pay mode: this client signs an EIP-3009 authorization and retries; the API settles it on Base
Inspect mode: MCP returns 402 details without signing or paying

Payment details:

Token: USDC on Base mainnet
Address: 0x60264c480b67adb557efEd22Cf0e7ceA792DefB7
Chain: Base (chain ID 8453)
Amount: 0.001–0.008 USDC per call (< 1 cent USD)

Tool Reference

`get_crypto_prices`

No parameters. Returns current prices for BTC, ETH, SOL + top 24h movers.

Cost: 0.001 USDC

`get_gas_prices`

No parameters. Returns gas prices for Ethereum, Base, Polygon, Arbitrum — slow/standard/fast tiers.

Cost: 0.001 USDC

`get_dex_quotes`

Get one ParaSwap aggregate route. No independent comparison between DEX venues.

Parameter	Type	Required	Description
`from`	string	✅	Input token (e.g. `"ETH"`, `"0x..."`)
`to`	string	✅	Output token (e.g. `"USDC"`)
`amount`	string	✅	Amount to swap (e.g. `"1.5"`)

Cost: 0.002 USDC

`scan_token`

Token security scan — detects rug-pull flags, honeypot patterns, mint authority, etc.

Parameter	Type	Required	Description
`token`	string	✅	Contract address or symbol (e.g. `"PEPE"`)

Cost: 0.003 USDC

`track_whales`

Top-holder sample from GoPlus. Gini and recent transfer history unavailable.

Parameter	Type	Required	Description
`token`	string	✅	Contract address or symbol

Cost: 0.005 USDC

`scan_yields`

Top DeFi yield opportunities across Aave, Compound, Morpho, Lido, Pendle, etc.

Parameter	Type	Required	Description
`chain`	string	❌	Filter by chain: `"ethereum"`, `"base"`, `"arbitrum"`, `"polygon"`
`min_tvl`	number	❌	Minimum TVL in USD (e.g. `1000000`)

Cost: 0.005 USDC

`get_funding_rates`

Hourly perpetual funding from Hyperliquid and dYdX v4. Spreads are indicative.

Parameter	Type	Required	Description
`asset`	string	❌	Asset symbol (e.g. `"BTC"`, `"ETH"`). All assets if omitted.

Cost: 0.008 USDC

`profile_wallet`

Observed priced wallet balances and available transaction counts. DeFi positions, PnL and risk score unavailable.

Parameter	Type	Required	Description
`address`	string	✅	Ethereum/Base wallet address (`0x...`)

Cost: 0.008 USDC

Development

git clone https://github.com/fernsugi/x402-api-mcp-server

cd x402-api-mcp-server

npm install npm run build npm start

To test without a payment wallet, simply run and see the 402 responses:

node dist/index.js

License

MIT

Three runnable workflows

Workflow	Tools	Total USDC
Token check	`scan_token` + `track_whales`	0.008
ETH funding	`get_funding_rates`	0.008
Swap quote + gas	`get_dex_quotes` + `get_gas_prices`	0.003

Runnable Node examples start in inspect mode. Each demo has inputs, recorded provider output, coverage limits, a spending cap, and an agent prompt.

Optional X402_REFERRAL_SOURCE labels requests for first-party aggregate attribution (default mcp). It is a hint, not verified caller identity. The API journals no raw payer wallets, IP addresses, or signatures. X402_EXPECTED_PAY_TO pins the payment recipient to the official wallet by default. Tools advertise that auto-pay can spend money and repeated calls can incur another charge.

Cursor / other local MCP clients

Use the same mcpServers configuration shown above. For Cursor, put it in .cursor/mcp.json in your project. Inspect mode needs no wallet. Set X402_MAX_PER_CALL_USDC before enabling auto-pay; repeated calls spend again. Keep wallet credentials in local environment settings, outside Git.

Registry publication

The Publish MCP Registry GitHub workflow validates the matching npm version, then publishes server.json using GitHub OIDC. It runs on a published GitHub release or a manual dispatch from main. No npm token, GitHub PAT, or wallet key is stored in CI. Actions and official publisher source are pinned to verified commits. npm publication still happens separately before creating the release.

X402 API

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

HotCodePush

README from the maker

@x402-api/mcp-server

Tools

Quick Start

Option A: Inspect mode (no payment needed)

Option B: Auto-pay mode (fully autonomous)

Claude Desktop Integration

Without auto-pay (inspect mode)

With auto-pay

Environment Variables

How x402 Payments Work

Tool Reference

get_crypto_prices

get_gas_prices

get_dex_quotes

scan_token

track_whales

scan_yields

get_funding_rates

profile_wallet

Development

Links

License

Three runnable workflows

Cursor / other local MCP clients

Registry publication

`get_crypto_prices`

`get_gas_prices`

`get_dex_quotes`

`scan_token`

`track_whales`

`scan_yields`

`get_funding_rates`

`profile_wallet`