io.github.halfkey/obol

obol

Pay the ferryman. Solana agent gateway via x402.

Obol is a pay-per-use Solana API for AI agents. No API keys, no subscriptions — agents pay per request in USDC using the x402 payment protocol. Solana's sub-cent transaction costs make micropayments viable for the first time.

Named after the coin placed on the tongue of the dead to pay Charon for passage across the River Styx. The original micropayment.

How it works

1. Agent requests data from a paid endpoint
2. Obol returns HTTP 402 with a payment requirement (amount, recipient, network)
3. Agent sends USDC on Solana matching the requirement
4. Agent retries with transaction proof in the X-PAYMENT header
5. Obol verifies on-chain and returns the data

No accounts. No tokens. No onboarding. Just pay and go.

Endpoints

Wallet Analytics

Endpoint	Price	Description
GET /api/v1/wallet/:addr/overview	$0.01	SOL balance, token count, total value
GET /api/v1/wallet/:addr/portfolio	$0.05	Full holdings with prices, NFTs, breakdown
GET /api/v1/wallet/:addr/activity	$0.05	Transaction history with categorization
GET /api/v1/wallet/:addr/risk	$0.10	Multi-factor risk assessment
GET /api/v1/wallet/:addr/pnl	$0.15	Token flow analysis, current values, P&L

Token Data

Endpoint	Price	Description
GET /api/v1/token/:mint/price	$0.005	Real-time price via Jupiter
GET /api/v1/token/:mint/metadata	$0.01	Name, symbol, supply, decimals

DeFi

Endpoint	Price	Description
GET /api/v1/defi/swap/quote	$0.005	Jupiter swap quote with route planning
POST /api/v1/defi/swap/execute	$0.25	Jupiter swap transaction builder
GET /api/v1/defi/positions/:addr	$0.10	DeFi positions — LSTs, LPs, lending
GET /api/v1/defi/lst/yields	$0.02	LST yield comparison across Solana

Free

Endpoint	Description
GET /	API info and pricing
GET /health	Service status
POST /api/v1/rpc	Proxied Helius RPC (allowlisted methods)

Agent Example

See examples/agent-client.ts for a full reference implementation. The key flow:

import { ObolAgent } from './examples/agent-client';

const agent = new ObolAgent();
await agent.discover();  // fetch pricing
agent.loadWallet(process.env.AGENT_PRIVATE_KEY);

// Auto-discovers price, pays, and returns data
const price = await agent.fetch('/api/v1/token/USDC_MINT/price');

Run in discovery-only mode (no wallet needed):

npx tsx examples/agent-client.ts

MCP Server

Obol ships as an MCP server — any AI agent that supports the Model Context Protocol can discover and call Obol's tools natively.

Install from npm

npm install -g obol-mcp

Claude Desktop / Claude Code

Add to your MCP config:

{
  "mcpServers": {
    "obol": {
      "command": "npx",
      "args": ["-y", "obol-mcp"],
      "env": {
        "OBOL_URL": "https://obol-production.up.railway.app"
      }
    }
  }
}

Or if developing locally:

{
  "mcpServers": {
    "obol": {
      "command": "npx",
      "args": ["tsx", "/path/to/obol/src/mcp.ts"],
      "env": {
        "OBOL_URL": "http://localhost:3000"
      }
    }
  }
}

Available MCP Tools

Tool	Description
obol_wallet_overview	SOL balance, token count, total value
obol_wallet_portfolio	Full holdings with prices and breakdown
obol_wallet_activity	Transaction history with categorization
obol_wallet_risk	Multi-factor risk assessment
obol_wallet_pnl	Token flow analysis and P&L
obol_token_price	Real-time price via Jupiter
obol_token_metadata	Name, symbol, supply, decimals
obol_swap_quote	Jupiter swap quote with routing
obol_swap_execute	Build swap transaction for signing
obol_defi_positions	LSTs, LPs, lending positions
obol_lst_yields	LST yield comparison
obol_health	API health check (free)
obol_info	Endpoint pricing and info (free)

Run locally

npm run mcp

Stack

• Fastify 5 — high-performance HTTP
• @x402/svm — official x402 SDK for Solana
• Helius — RPC + DAS API
• Jupiter — token prices + swap execution
• Upstash Redis — cache + payment receipts
• TypeScript — full type safety
• Zod — runtime validation

Setup

git clone https://github.com/halfkey/obol.git
cd obol
npm install
cp .env.example .env
# Edit .env with your Helius key and merchant wallet address
npm run dev

Testing

# Unit + integration tests (46 tests)
npm test -- --run

# Smoke test against live deployment
npx tsx scripts/smoke-test.ts https://obol-production.up.railway.app

# Manual payment test
npx tsx scripts/test-payment.ts <tx-signature>

Environment

See .env.example. Key variables:

• PAYMENT_MODE — mock (dev, auto-approve) or onchain (production)
• PAYMENT_RECIPIENT_ADDRESS — your Solana wallet that receives USDC
• HELIUS_API_KEY — Helius RPC access
• UPSTASH_REDIS_REST_URL / TOKEN — cache layer

Roadmap

• 11 paid endpoints (wallet, token, DeFi, LST, P&L)
• On-chain USDC verification with replay prevention
• Test suite (46 vitest + 20-point smoke test)
• Agent client reference implementation
• GitHub Actions CI
• WebSocket subscriptions for wallet monitoring
• Dynamic congestion-based pricing
• Multi-chain support

License

MIT