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

Agent requests data from a paid endpoint
Obol returns HTTP 402 with a payment requirement (amount, recipient, network)
Agent sends USDC on Solana matching the requirement
Agent retries with transaction proof in the X-PAYMENT header
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:

server.ts

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):

Terminal

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

Terminal

npm install -g obol-mcp

Claude Desktop / Claude Code

Add to your MCP config:

config.json

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

Or if developing locally:

config.json

{
  "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

Terminal

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

bash

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

bash

# 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