spanDEX Trader

Trade tokens on Base using spanDEX, the open-source meta-aggregator. Supports market swaps (races 6 providers for best price with automatic fallback), limit orders via KyberSwap, balance checks, and provider comparison. Works with all token types including Clanker V4, Flaunch DERC20, and standard ERC-20. Use when the user wants to swap tokens, place limit orders, check wallet balances, or execute trades on Base chain. Triggers on "swap", "buy", "sell", "trade", "limit order", "spanDEX", "best price", "meta-aggregator".

Trade on Base chain using spanDEX — the free, open-source meta-aggregator by @_nonlinear / Fabric.

Races 6 DEX aggregators (Fabric, KyberSwap, Odos, Velora, LI.FI, Relay) per swap, simulates on-chain, picks the winner, and executes with automatic fallback if the best-priced provider fails.

Setup

Prerequisites: Node.js 18+, npm

bash

# Install dependencies (run once in skill directory)
cd <skill-dir>/scripts && npm init -y && npm i viem @spandex/core

Required env vars:

Var	Purpose
BASE_RPC_URL	Base chain RPC endpoint (Alchemy, Infura, dRPC, etc.)
SPANDEX_PRIVATE_KEY	Wallet private key (hex). OR use SPANDEX_KEY_PATH for file-based key

Optional env vars:

Var	Default	Purpose
SPANDEX_KEY_PATH	—	Path to file containing private key (alternative to raw key)
SPANDEX_APP_ID	spandex-trader-skill	App identifier for provider APIs
SPANDEX_STRATEGY	bestPrice	Default quote strategy
SPANDEX_PRIORITY_GWEI	0.03	Priority fee floor (gwei) for Base sequencer
SPANDEX_SKIP_LOCK	—	Set 1 to disable anti-double-execution lock
SPANDEX_DEBUG	—	Enable debug logging

Commands

All output is JSON. TOKEN can be a contract address or alias (USDC, WETH, ETH, DAI, USDT).

bash

# Compare prices across all 6 providers
node scripts/spandex_trade.mjs quote --sell USDC --buy 0xTOKEN --amount 50

# Execute swap (best price, automatic fallback)
node scripts/spandex_trade.mjs swap --sell USDC --buy 0xTOKEN --amount 50
node scripts/spandex_trade.mjs swap --sell USDC --buy 0xTOKEN --amount 50 --slippage 500 --dry-run

# KyberSwap limit orders (gasless EIP-712)
node scripts/spandex_trade.mjs limit --sell 0xTOKEN --buy USDC --sell-amount 1000000 --buy-amount 50 --expiry 7d
node scripts/spandex_trade.mjs orders --status active
node scripts/spandex_trade.mjs cancel-order --order-id 123

# Wallet
node scripts/spandex_trade.mjs balance
node scripts/spandex_trade.mjs balance --token 0xTOKEN
node scripts/spandex_trade.mjs providers

Slippage defaults

Auto-applied based on token pair:

• Major ↔ Major (USDC/WETH/ETH): 0.5% (50 bps)
• Major ↔ Microcap: 3% (300 bps)
• Microcap ↔ Microcap: 5% (500 bps)

Override with --slippage <bps>.

Execution flow

1. getQuotes() — fetch + simulate from all 6 providers in parallel
2. sortQuotesByPerformance() — rank by output amount (best first)
3. For each quote: buildCalls() → sendTransaction() with priority fee → if fail, try next provider
4. netOutputs() — extract actual output from TX receipt logs
5. Final balance verification

Key behaviors

• Anti-double-execution: 120s lockfile per token prevents accidental duplicate swaps
• Fallback routing: If best-price provider fails execution, automatically tries next
• V4/DERC20 compatible: Uses buildCalls() for proper Clanker V4 and Flaunch DERC20 settlement
• No API keys needed: All 6 providers work without registration

Token compatibility by provider

Provider	Standard ERC-20	Clanker V4	Flaunch DERC20
KyberSwap	✅	✅	✅
LI.FI	✅	✅	✅
Fabric	✅	⚠️	⚠️
Odos	✅	❌	❌
Velora	✅	❌	❌
Relay	✅	⚠️	⚠️

For detailed integration notes and architecture, see references/INTEGRATION.md.