AgentPay — Ditch those API keys.

Pay per call. No subscriptions. No human in the loop.

AgentPay is an x402 payment gateway for AI agents. Access 14 crypto data tools using USDC on Stellar or Base — agents discover, pay, and get data back autonomously, within a hard budget cap.

→ 14 live tools: token prices, open interest, orderbook depth, whale activity, funding rates, gas tracker, DeFi TVL, Fear & Greed, yield scanner, token security, Dune queries and more → Budget-aware Session: agents estimate costs, track spend, never exceed budget → x402 protocol: works with any x402-compatible agent → Stellar + Base: pay with USDC on either network — Stellar (5s, ~$0.00001 fee) or Base mainnet (2s, ~$0.0001 fee)

Live gateway (mainnet): https://gateway-production-2cc2.up.railway.app

---

Quickstart — 3 steps

Step 1: Get a wallet with USDC

Option A — Stellar mainnet (recommended)

Send USDC to a Stellar wallet via Coinbase, Lobstr, or any Stellar DEX. Then use your Stellar secret key (S...) directly.

USDC issuer on Stellar mainnet: GA5ZSEJYB37JRC5AVCIA5MOP4RHTM335X2KGX3IHOJAPP5RE34K4KZVN Gateway: https://gateway-production-2cc2.up.railway.app — use network="mainnet"

Option B — Base mainnet (alternative)

Send USDC to an EVM wallet on Base. Use your EVM private key with network="base".

USDC contract on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 Gateway: https://gateway-production-2cc2.up.railway.app — use network="base"

Option C — Testnet (free, no wallet needed)

One command gives you a Stellar testnet wallet pre-loaded with 5 USDC:

curl https://gateway-testnet-production.up.railway.app/faucet

Use network="testnet" and gateway_url="https://gateway-testnet-production.up.railway.app" in your Session.

---

Step 2: Create a Session with a budget

from agent.wallet import AgentWallet, Session, BudgetExceeded

# Option A — Stellar mainnet
wallet = AgentWallet(secret_key="S...", network="mainnet")
GATEWAY = "https://gateway-production-2cc2.up.railway.app"

# Option C — Testnet (faucet wallet)
# wallet = AgentWallet(secret_key="S...", network="testnet")
# GATEWAY = "https://gateway-testnet-production.up.railway.app"

with Session(wallet=wallet, gateway_url=GATEWAY, max_spend="0.05") as session:
    print(f"Balance:  {wallet.get_usdc_balance()} USDC")
    print(f"Budget:   {session.remaining()} remaining")

The Session enforces a hard USDC cap across all calls. It raises BudgetExceeded before any payment goes out if a tool would push you over, and automatically falls back to the next-cheapest tool in the same category when the preferred one is too expensive.

---

Step 3: Call tools — payment is automatic

with Session(wallet=wallet, gateway_url=GATEWAY, max_spend="0.05") as session:

    # Token price — $0.001
    r = session.call("token_price", {"symbol": "ETH"})
    print(f"ETH: ${r['price_usd']:,.2f}  ({r['change_24h_pct']:+.2f}% 24h)")

    # Open interest — $0.002
    r = session.call("open_interest", {"symbol": "ETH"})
    print(f"ETH OI: ${r['total_oi_usd']/1e9:.2f}B  ({r['oi_change_24h_pct']:+.2f}% 24h)")

    # Orderbook depth — $0.002
    r = session.call("orderbook_depth", {"symbol": "ETHUSDT"})
    slip = next(d['slippage_pct'] for d in r['depth'] if d['notional_usd'] == 250_000)
    print(f"ETH $250k slippage: {slip:.3f}%")

    # Funding rates — $0.003
    r = session.call("funding_rates", {"asset": "ETH"})
    for ex in r.get("exchanges", [])[:2]:
        print(f"  {ex['exchange']}: {ex['funding_rate_pct']:+.4f}%/8h")

    print(f"\nTotal spent: {session.spent()}")
    print(f"Remaining:   {session.remaining()}")

Each session.call() handles the full x402 flow internally:

1. Checks your remaining budget against the tool's price (pre-flight, no payment yet)
2. POSTs to the gateway, receives a 402 with {payment_id, amount_usdc, pay_to}
3. Sends USDC on Stellar — confirmed in ~3–5 seconds
4. Retries the request with X-Payment: tx_hash=<hash>,from=<addr>,id=<payment_id>
5. Returns the data

---

Available Tools

Tool	Price	Parameters	Returns
token_price	$0.001	symbol (BTC, ETH, SOL…)	price_usd, change_24h_pct, market_cap_usd
gas_tracker	$0.001	—	slow/standard/fast gwei, base_fee_gwei
fear_greed_index	$0.001	limit (days of history, default 1)	value 0–100, value_classification, history[]
token_market_data	$0.001	token_a, token_b	volume_24h_usd, market_cap_usd, price_usd
wallet_balance	$0.002	address, chain (ethereum/stellar)	token balances
whale_activity	$0.002	token, min_usd (default 100k)	large_transfers[] with exchange direction, total_volume_usd
defi_tvl	$0.002	protocol (optional, e.g. "uniswap")	tvl, change_1d, change_7d, chains[]
token_security	$0.002	contract_address, chain (ethereum/bsc)	risk_level, is_honeypot, buy_tax, sell_tax
open_interest	$0.002	symbol (BTC, ETH…)	total_oi_usd, oi_change_1h_pct, oi_change_24h_pct, long_short_ratio, exchanges[]
orderbook_depth	$0.002	symbol (e.g. ETHUSDT), exchange (binance/bybit)	best_bid, best_ask, spread_pct, slippage at $10k/$50k/$250k
funding_rates	$0.003	asset (optional, e.g. "BTC")	funding_rate_pct, annualized_rate_pct, sentiment per exchange
crypto_news	$0.003	currencies (e.g. "ETH,BTC"), filter (hot/new/rising)	headlines[] with title, url, sentiment, score
yield_scanner	$0.004	token, chain (optional), min_tvl (default $1M)	top 10 pools by APY with protocol, tvl_usd, risk_level
dune_query	$0.005	query_id, limit (default 25), fast_only (bool)	rows[], columns[], row_count from Dune Analytics

Discover all tools dynamically:

import httpx
tools = httpx.get(f"{GATEWAY}/tools").json()["tools"]
for t in tools:
    print(f"{t['name']:<22} ${t['price_usdc']}  — {t['description']}")

---

The derivatives demo

"My bot read funding rates (+0.08%/8h on ETH), confirmed rising open interest (+12% in 24h), checked orderbook depth ($0.31% slippage on a $250k sell), and decided not to open the short. Total data cost: $0.007."

with Session(wallet=wallet, gateway_url=GATEWAY, max_spend="0.05") as session:

    rates = session.call("funding_rates", {"asset": "ETH"})
    oi    = session.call("open_interest", {"symbol": "ETH"})
    depth = session.call("orderbook_depth", {"symbol": "ETHUSDT"})

    top_rate   = max(rates["exchanges"], key=lambda x: x["funding_rate_pct"])
    oi_24h     = oi["oi_change_24h_pct"]
    slip_250k  = next(d["slippage_pct"] for d in depth["depth"] if d["notional_usd"] == 250_000)

    print(f"Funding:  {top_rate['funding_rate_pct']:+.4f}%/8h on {top_rate['exchange']}")
    print(f"OI 24h:   {oi_24h:+.2f}%")
    print(f"Slippage: {slip_250k:.3f}% on a $250k sell")
    print(f"Cost:     {session.spent()}")

---

Payment Options

AgentPay accepts USDC payments on two networks:

• Stellar — ~$0.00001 per tx, 5-second settlement (recommended for agents using the Python SDK)
• Base — ~$0.0001 per tx, 2-second settlement (EIP-3009 transferWithAuthorization on Base mainnet)

The gateway's 402 response advertises both options simultaneously. Clients pick the network that suits them — no configuration required on the tool side.

Stellar Payment Verification

Stellar payments are verified on-chain via Stellar Horizon. The gateway checks that the transaction exists, is confirmed, sends USDC to the gateway address, and the amount matches the quoted price — all without requiring agents to trust a third party.

Base payments use Mode B direct on-chain settlement: the client calls transferWithAuthorization on the USDC contract and sends the tx_hash in the PAYMENT-SIGNATURE header. The gateway verifies the receipt via JSON-RPC.

---

MCP Server

AgentPay ships a Model Context Protocol server that gives Claude Desktop (and any MCP client) direct access to all 14 tools. Payments happen automatically in the background using Stellar USDC.

See README_MCP.md for setup instructions.

Quick config (claude_desktop_config.json):

{
  "mcpServers": {
    "agentpay": {
      "command": "python",
      "args": ["/path/to/agentpay/gateway/mcp_server.py"],
      "env": {
        "STELLAR_SECRET_KEY": "S...",
        "AGENTPAY_GATEWAY_URL": "https://gateway-production-2cc2.up.railway.app"
      }
    }
  }
}

Or via npm:

npx @romudille/agentpay-mcp

---

Without the SDK — raw HTTP

The x402 flow works with any HTTP client in any language.

GATEWAY="https://gateway-production-2cc2.up.railway.app"
AGENT_ADDR="G..."   # your Stellar public key

# 1. Call the tool → receive 402 payment challenge
RESPONSE=$(curl -s -X POST "$GATEWAY/tools/token_price/call" \
  -H "Content-Type: application/json" \
  -d "{\"parameters\":{\"symbol\":\"ETH\"},\"agent_address\":\"$AGENT_ADDR\"}")

PAYMENT_ID=$(echo $RESPONSE | python3 -c "import sys,json; print(json.load(sys.stdin)['payment_id'])")
AMOUNT=$(echo $RESPONSE    | python3 -c "import sys,json; print(json.load(sys.stdin)['amount_usdc'])")
PAY_TO=$(echo $RESPONSE    | python3 -c "import sys,json; print(json.load(sys.stdin)['pay_to'])")

# 2. Send USDC on Stellar (memo = payment_id)
TX_HASH=$(python3 -c "
from stellar_sdk import Keypair, Server, Network, Asset, TransactionBuilder
kp = Keypair.from_secret('S...')
server = Server('https://horizon.stellar.org')
acct = server.load_account(kp.public_key)
tx = (TransactionBuilder(acct, Network.PUBLIC_NETWORK_PASSPHRASE, base_fee=100)
      .add_text_memo('$PAYMENT_ID'[:28])
      .append_payment_op('$PAY_TO', Asset('USDC','GA5ZSEJYB37JRC5AVCIA5MOP4RHTM335X2KGX3IHOJAPP5RE34K4KZVN'), '$AMOUNT')
      .set_timeout(30).build())
tx.sign(kp)
print(server.submit_transaction(tx)['hash'])
")

# 3. Retry with payment proof → get data
curl -s -X POST "$GATEWAY/tools/token_price/call" \
  -H "Content-Type: application/json" \
  -H "X-Payment: tx_hash=$TX_HASH,from=$AGENT_ADDR,id=$PAYMENT_ID" \
  -d "{\"parameters\":{\"symbol\":\"ETH\"},\"agent_address\":\"$AGENT_ADDR\"}"

---

Session API reference

# Pre-check price without paying
price = session.estimate("dune_query")       # "$0.005"

# Check headroom before committing
if not session.would_exceed("0.005"):
    result = session.call("dune_query", {"query_id": 3810512, "limit": 10})

# Access spend state mid-session
session.spent()        # "$0.004"
session.remaining()    # "$0.046"

# Full breakdown after session closes
summary = session.summary()
# {
#   "calls": 3,
#   "spent_usdc": "0.007",
#   "spent_fmt": "$0.007",
#   "remaining_fmt": "$0.043",
#   "breakdown": [
#     {"tool": "funding_rates",   "amount_usdc": "0.003", "tx_hash": "abc123..."},
#     {"tool": "open_interest",   "amount_usdc": "0.002", "tx_hash": "def456..."},
#     {"tool": "orderbook_depth", "amount_usdc": "0.002", "tx_hash": "ghi789..."}
#   ]
# }

---

Run the demo

git clone https://github.com/romudille-bit/agentpay && cd agentpay
python -m venv venv && source venv/bin/activate
pip install -r requirements.txt

# Copy env and add your Stellar secret key
cp .env.example .env

# Week 2 demo — open_interest + orderbook_depth on mainnet ($0.004)
WEEK2_NETWORK=mainnet STELLAR_SECRET_KEY=S... python agent/week2_test.py

# Full 5-tool ETH analysis (~$0.012)
AGENTPAY_GATEWAY_URL=https://gateway-production-2cc2.up.railway.app \
  python agent/budget_demo.py

---

Architecture

agent (Python SDK)
    │
    │  POST /tools/{name}/call
    │  ← 402 {payment_options: {stellar: {...}, base: {...}}}
    │  → Stellar USDC payment (~3–5s)  OR  Base transferWithAuthorization (~2s)
    │  → retry with X-Payment or PAYMENT-SIGNATURE header
    │  ← 200 {result: ...}
    ▼
gateway (FastAPI on Railway)
    │
    ├── registry/registry.py   — 14-tool catalog with prices & dev wallets
    ├── gateway/stellar.py     — Stellar payment verification via Horizon
    ├── gateway/base.py        — Base payment verification via JSON-RPC
    └── gateway/main.py        — real API dispatchers
            ├── CoinGecko         token_price, token_market_data
            ├── Etherscan V2      gas_tracker, whale_activity, wallet_balance
            ├── DeFiLlama         defi_tvl, yield_scanner
            ├── alternative.me    fear_greed_index
            ├── Reddit            crypto_news
            ├── Dune Analytics    dune_query
            ├── GoPlus            token_security
            └── Binance+Bybit+OKX funding_rates, open_interest, orderbook_depth

Fee model: Gateway charges 15% (GATEWAY_FEE_PERCENT=0.15), forwards the rest to each tool developer's Stellar wallet. All payments settle on-chain in ~3–5 seconds.

---

Discovery

Directories & Listings

Directory	Status
x402scout	✅ indexed, health-checked every 15min
Glama MCP	✅ listed
402index.io	🔜 needs update — 14 tools
awesome-x402	✅ listed
npm	🔜 v1.1.0 pending publish
xpay.tools	🔜 submission in progress

Agent-Readable Endpoints

AgentPay is discoverable by autonomous agents at standard well-known paths:

Endpoint	Purpose
/.well-known/agentpay.json	AgentPay manifest
/.well-known/agent.json	A2A agent card
/.well-known/l402-services	402index.io discovery format
/llms.txt	LLM-readable service description (tools + integration guide)
/sitemap.xml	17-URL sitemap

Any x402-compatible agent can discover and use AgentPay tools without human setup.