OpenDexter

x402 payments for AI agents — search, pay, and build with paid APIs.
Skills, rules, tools, and an MCP server for Claude Code, Cursor, and any MCP client.

Browse Marketplace  |   x402 Protocol  |   SDK Docs

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Install

There are two ways to run OpenDexter. Hosted is the fastest: nothing to install, and the wallet is a session you fund with a QR code. Local runs the MCP server on your machine with a self-custodied wallet key.

Hosted (no install)

Add the hosted MCP server to any MCP client's config. There is nothing to download; you pair and fund a session wallet at dexter.cash.

{
  "mcpServers": {
    "opendexter": {
      "url": "https://open.dexter.cash/mcp"
    }
  }
}

That is the whole setup. Skip to Fund your wallet.

Local (self-custody)

Runs @dexterai/opendexter on your machine; the wallet key lives in ~/.dexterai-mcp/wallet.json.

Claude Code. Install the plugin (skills, rules, agent, commands, and the MCP server). Do not also add the hosted or local server by hand. The plugin already includes it.

claude plugins marketplace add Dexter-DAO/opendexter-ide
claude plugins install opendexter

Cursor

npx @dexterai/opendexter@latest install --client cursor

Any other MCP client. The installer covers Codex, VS Code, Windsurf, and Gemini CLI:

npx @dexterai/opendexter@latest install --client <codex|vscode|windsurf|gemini-cli>

Or add the server to your client's MCP config by hand:

{
  "mcpServers": {
    "opendexter": {
      "command": "npx",
      "args": ["-y", "@dexterai/opendexter@latest"]
    }
  }
}

Fund your wallet

A paid call needs USDC. After install, fund whichever wallet you are using:

• Hosted: pair the session at dexter.cash and fund it with the QR code.
• Local: send USDC (Solana or Base) to the address printed during install, or run the card_issue tool to set up a Dextercard and fund calls from that.

Your agent can call x402_wallet at any time to show the address and current balance.

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What This Plugin Does

This plugin ships with a real MCP server that gives your agent live tools for searching, paying for, and calling paid APIs. On top of that, it has deep SDK knowledge so the agent can help you build x402 payments into your own projects.

After installing, your agent can immediately:

• Search the Dexter Marketplace for any paid API (image generation, DeFi, analytics, AI, games — thousands of endpoints)
• Check what an API costs before paying
• Pay and call any x402 API with automatic USDC settlement
• Help you build x402 clients, servers, React apps, Stripe integrations, and access passes

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What is x402?

x402 is an open protocol for machine-to-machine payments over HTTP. When an API returns 402 Payment Required, it includes payment instructions. The client pays (USDC on Solana, Base, or other chains), and the API delivers the response. No API keys, no subscriptions, no invoices.

Dexter operates the most-used x402 facilitator at https://x402.dexter.cash, processing millions of settlements across thousands of indexed endpoints from every major x402 facilitator — Dexter, Coinbase, PayAI, and more.

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Plugin Contents

MCP Server — @dexterai/opendexter

Seven tools cover everything:

Tool	Description
x402_search	Semantic capability search over thousands of paid APIs. Returns tiered results (strong + related matches) ranked by quality, usage, and reputation.
x402_check	Preview pricing per chain without spending anything. See exactly what an API costs before committing.
x402_fetch	Call any x402 API with automatic USDC payment. Signs, pays, retries — returns the response directly with an on-chain settlement receipt.
x402_pay	Alias for x402_fetch.
x402_access	Access identity-gated endpoints with wallet proof (Sign-In-With-X).
x402_wallet	Show wallet address, USDC/SOL balances, and deposit instructions.
x402_settings	Read or update your per-call spending limit.

Two wallets are auto-created at ~/.dexterai-mcp/wallet.json on first run — one Solana, one EVM. Fund either address with USDC and your agent can start paying for APIs immediately.

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Skills (6)

Deep knowledge the agent invokes when relevant:

Skill	What it teaches
opendexter	How to use the x402 tools: search → check → fetch workflow, quality scores, funding flows, error recovery
x402-client	Build x402 clients: wrapFetch(), createX402Client(), Budget Accounts for agents, Sponsored Access, keypair wallets, access passes
x402-server	Add x402 paywalls: x402Middleware() with multi-chain accept, Stripe PayTo, dynamic/token pricing, access passes, sponsored access injection
x402-react	React hooks: useX402Payment() (payment state, balances, tx info), useAccessPass() (tier discovery, purchase, auto-fetch)
x402-protocol	v2 spec: core types, payment flow, 3 schemes (exact, upto, bridge), HTTP/MCP/A2A transports, all CAIP-2 networks, error codes
x402-debugging	Diagnose failures: 27 SDK error codes, facilitator health, fee payer safety, retry support, pre-payment callbacks

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Rules (2, always-on)

Injected into every conversation so the agent always knows the fundamentals:

• x402-protocol — CAIP-2 network identifiers, header conventions, atomic units, facilitator URL, supported chains
• x402-coding — Import from subpaths (@dexterai/x402/client), prefer wrapFetch() for agents, x402Middleware() for servers

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Agent

• x402-engineer — Specialized persona that knows the full Dexter x402 stack. Validates amounts and balances before payment, never exposes private keys, reaches for x402_search whenever a user mentions paid APIs.

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Commands (3)

Command	What it does
setup-opendexter	Install the OpenDexter MCP server into Cursor, Claude Code, Codex, VS Code, Windsurf, or Gemini CLI.
setup-x402-client	Add @dexterai/x402 to a Node.js project with wrapFetch() boilerplate and a test call.
setup-x402-server	Add x402Middleware() to an Express app with paywall configuration and test.

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Supported Chains

Chain	Network ID (CAIP-2)	Gas Token
Solana	solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp	SOL
Base	eip155:8453	ETH
Polygon	eip155:137	POL
Arbitrum	eip155:42161	ETH
Optimism	eip155:10	ETH
Avalanche	eip155:43114	AVAX
BSC (BNB Chain)	eip155:56	BNB
SKALE Base	eip155:1187947933	sFUEL (free)

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Links

• Dexter Marketplace — Browse thousands of paid APIs
• Dexter Facilitator — Payment infrastructure
• @dexterai/x402 SDK — Build x402 clients and servers
• @dexterai/opendexter — MCP gateway for AI agents
• x402 Protocol Spec — The open standard
• Become a Seller — List your API on the marketplace
• Twitter
• Telegram

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License

MIT