PipRail

PipRail — Agent Payment Wallet 🛤️

Give your OpenClaw agent a self-custodial crypto payment wallet with a hard spend cap it can't exceed. It autonomously pays x402 "402 Payment Required" paywalls across every major chain — settling funds straight to the recipient's wallet, with no facilitator, no fee, no signup.

No API key. No account. No signup. PipRail is self-custodial — you bring a wallet you control. It even runs read-only with zero config: discover, quote, register, budget, and guide work the moment it starts, no key at all. Add your own wallet key (PIPRAIL_PRIVATE_KEY) only when the agent should actually pay — it's a wallet signing key you hold, never an API credential, and it never leaves your machine.

PipRail plugs into OpenClaw as a standard MCP server — the published @piprail/mcp (npx -y @piprail/mcp) over stdio — so the agent gets all 8 tools natively, capped by a budget it can't exceed.

Why PipRail (vs every other crypto skill)

Every other OpenClaw payment skill routes through a facilitator or custodian that holds keys and/or takes a cut. PipRail is different:

• Backendless — no facilitator, no hosted service. Payments verify locally against your own RPC.
• No fee — funds settle straight to the service provider's wallet. PipRail takes nothing.
• Self-custodial — your key, your machine. PipRail hosts and holds nothing.
• Every major chain — EVM (Base, Ethereum, Polygon, Arbitrum, Optimism, Avalanche, BNB…), Solana, TON, Tron, NEAR, Sui, Aptos, Algorand, Stellar, XRPL — one PIPRAIL_CHAIN param picks everything.
• Gasless when you want it — opt into the standard x402 exact rail (PIPRAIL_SCHEMES=exact) and the agent pays zero gas: it signs the transfer (EIP-3009/Permit2 on EVM, SVM on Solana) and the server settles.
• A hard spend cap the model can't cross — PIPRAIL_MAX_TOTAL=5.00 and that's the ceiling, enforced in the SDK before any on-chain send. MIT open source.

The 8 tools your agent gets

Only piprail_pay_request moves funds. Six tools — discover, quote, register, budget, guide, verify_receipt — work with no key at all; pay and plan (it reads your balance) need your wallet.

Install

Discover + install on ClawHub (either command works):

clawhub install piprail            # the ClawHub CLI
openclaw skills install piprail     # …or OpenClaw's native command

Then wire the MCP server into ~/.openclaw/openclaw.json — OpenClaw nests servers under mcp.servers. No key is needed — this is the whole config, and it starts the server read-only (discover / quote / register / budget / guide all work):

{ "mcp": { "servers": { "piprail": {
  "command": "npx", "args": ["-y", "@piprail/mcp"],
  "env": { "PIPRAIL_CHAIN": "base" }
} } } }

Want the agent to actually pay? Then — and only then — add your own self-custodial wallet key plus a budget cap (PIPRAIL_PRIVATE_KEY is a wallet signing key you hold, never an API key):

{ "mcp": { "servers": { "piprail": {
  "command": "npx", "args": ["-y", "@piprail/mcp"],
  "env": { "PIPRAIL_CHAIN": "base", "PIPRAIL_MAX_TOTAL": "5.00", "PIPRAIL_PRIVATE_KEY": "0xYOUR_KEY" }
} } } }

Restart OpenClaw (or run openclaw mcp set) and the piprail_* tools appear. See Configure below.

Configure

Defaults are deliberately small and safe (0.10 per payment, 10.00 lifetime, USDC on Base). Start there, raise as you trust it.

The agent workflow

discover → quote → plan → pay. A typical session:

User:  Find me a crypto price API I can pay for.
Agent: [piprail_discover("crypto price")]  → cheapest is 0.001 USDC/call on Base.
User:  Can I afford it?
Agent: [piprail_plan_payment(url)]  → yes; 4.82 USDC left of 5.00, recipient ready, gas ~$0.05.
User:  Get me the ETH price.
Agent: [piprail_pay_request(url)]  → paid 0.001 USDC (tx 0x…). ETH: $3,247.18. 4.819 USDC left.

Learn more

• Docs: docs.piprail.com/integrations/openclaw · the 8 tools · spend controls
• Source (MIT): github.com/piprail/piprail — ⭐ a star helps others find it
• Follow: @piprailhq on X — new chains, ship logs, agent-payment tips
• Live payable demo: piprail.com/x402/demo