Otto X — x402 DeFi API on X Layer

Built for the OKX Build X Hackathon — Season 2

Otto X is a pay-per-call DeFi API on X Layer powered by the x402 protocol. AI agents and developers pay micro-fees ($0.001–$0.50) per request — no API keys, no subscriptions, no accounts. The on-chain payment IS the authentication.

Live: xlayer.ottoai.services
Agentic Wallet: 0xa3db6825de8222e9f8bac136eeb2f65d49a88fcf

Endpoints (15 Paid + 5 Free)

X Layer DEX (OKX DEX Aggregator)

Endpoint	Price	Description
POST /swap	$0.01	DEX swap quotes + unsigned calldata
GET /market-alpha	$0.005	Live token pricing from DEX quotes
GET /price?token=0x...	$0.002	Single token USD price
GET /all-tokens	$0.002	All tokens on X Layer DEX
GET /approve?token=0x...&amount=N	$0.005	ERC-20 approval calldata

Market Intelligence

Endpoint	Price	Description
GET /crypto-news	$0.001	Real-time crypto news with sentiment
GET /token-alpha?symbol=BTC	$0.10	Premium token intelligence
GET /kol-sentiment	$0.10	Aggregated KOL sentiment (top 50)
GET /trending-altcoins	$0.10	Top 3 trending altcoins
GET /mega-report	$0.25	Comprehensive daily market briefing
GET /token-security?address=0x...	$0.10	Contract security audit
GET /funding-rates?symbol=BTC	$0.10	Derivatives funding rates & OI
GET /defi-analytics?protocol=aave	$0.10	DeFi protocol analytics

AI Tools

Endpoint	Price	Description
GET /generate-meme?prompt=...	$0.50	AI image generation (Gemini)
GET /llm-research?prompt=...	$0.50	AI research assistant

Free

Endpoint	Description
GET /	Landing page + JSON discovery
GET /health	Service health check
GET /tokens	Curated token registry (16 tokens)
GET /llm.txt	AI-readable service catalog
GET /.well-known/x402	x402 discovery document

How x402 Works

1. Send request  →  POST /swap
2. Get 402       ←  Payment Required ($0.01, X Layer address)
3. Pay on-chain  →  Transfer on X Layer mainnet
4. Retry + proof →  POST /swap + payment header
5. Get data      ←  Swap quote + calldata

No API keys. No OAuth. No accounts. The payment IS the authentication.

Architecture

Client (AI Agent or Developer)
    │
    │ HTTP + x402 payment header
    ▼
┌────────────────────────────────────────┐
│            Otto X Server               │
│                                        │
│  x402 Middleware (OKX Facilitator)      │
│  Verifies on-chain payment on X Layer  │
│                                        │
│  ┌──────────┐  ┌────────────────────┐  │
│  │ DEX      │  │ Proxy Routes       │  │
│  │ Routes   │  │ (Market Intel,     │  │
│  │ (OKX     │  │  AI Tools)         │  │
│  │  Aggr.)  │  │                    │  │
│  └──────────┘  └────────────────────┘  │
└────────────────────────────────────────┘
         │                    │
    OKX DEX API        Otto AI Agents
    (X Layer)          (Market Alpha,
                        Tools Agent)

OKX Onchain OS Usage

Module	Usage
x402 SDK (@okxweb3/x402-express, @okxweb3/x402-evm, @okxweb3/x402-core)	Payment middleware gating all 15 paid endpoints via OKXFacilitatorClient on X Layer
DEX Aggregator API v6	HMAC-authenticated calls for swap quotes, token pricing, registry, and approvals on chain 196
Agentic Wallet	Project on-chain identity created via Onchain OS CLI
OKX API Auth	HMAC-SHA256 request signing for all DEX interactions

Token Registry (16 Curated Tokens)

Category	Tokens
Native	OKB
Stablecoins	USDT, USDG, USDC, USDe, frxUSD
Wrapped	WETH, WOKB, XBTC, XETH, XSOL, XOKSOL
DeFi	sUSDe, rsETH, LINK
Meme	XDOG

The paid /all-tokens endpoint returns the full list from OKX DEX (100+ tokens).

Quick Start

git clone https://github.com/useOttoAI/otto-x.git
cd otto-x
npm install
cp .env.example .env
# Fill in OKX API credentials + payment address
npm run dev

# Health check (free)
curl http://localhost:4196/health

# Token list (free)
curl http://localhost:4196/tokens

# Swap quote (returns 402 — payment required)
curl -X POST http://localhost:4196/swap \
  -H "Content-Type: application/json" \
  -d '{"fromToken":"USDT","toToken":"OKB","amount":"10","userWalletAddress":"0x..."}'

Project Structure

src/
  config/
    env.ts              # Environment variables
    x402.ts             # x402 route pricing (15 endpoints)
  lib/
    amounts.ts          # Token decimal conversion
    logger.ts           # Structured logging
    tokens.ts           # Curated 16-token registry
  okx/
    auth.ts             # HMAC-SHA256 request signing
    dex-client.ts       # OKX DEX Aggregator client
    http.ts             # Authenticated HTTP client
    market-client.ts    # Token pricing via DEX quotes
  routes/
    dex.ts              # /price, /all-tokens, /approve
    market-alpha.ts     # /market-alpha
    proxy.ts            # Proxied market intel + AI tools
    swap.ts             # /swap
  services/
    market-alpha-service.ts
    swap-service.ts
  types/
    okx.ts
    swap.ts
  index.ts              # Server, landing page, middleware

Team

Otto AI — autonomous DeFi agent infrastructure.

• Website: useotto.xyz
• Docs: docs.useotto.xyz
• Twitter: @useOttoAI

License

MIT