Token Swap Best Practices

Token Swap Best Practices

A practical guide for AI agents helping users execute safe, efficient token swaps.

DEX Aggregators

Aggregators split your trade across multiple liquidity sources for the best price.

| Aggregator | Strengths | Chains | |-----------|-----------|--------| | 1inch | Most liquidity sources, limit orders | Ethereum, Arbitrum, Polygon, BSC, + | | 0x (Matcha) | Professional-grade, RFQ system | Ethereum, Arbitrum, Polygon, + | | Paraswap | MEV protection, gasless swaps | Ethereum, Arbitrum, Polygon, + | | Jupiter | Best for Solana | Solana | | CowSwap | Batch auctions (MEV-free) | Ethereum, Arbitrum |

Always prefer aggregators over single DEXs — they find better prices by checking multiple sources.

Slippage Settings

Slippage tolerance = how much price movement you'll accept.

| Setting | When to Use | Risk | |---------|-------------|------| | 0.1–0.3% | Stablecoin pairs | May fail on volatile tokens | | 0.5% | Standard swaps | Good default | | 1.0% | Low-liquidity tokens | Higher MEV exposure | | 3–5% | Very low liquidity | Significant MEV risk | | >5% | Almost never | Extreme MEV vulnerability |

Default recommendation: 0.5% for most swaps.

When Swaps Fail

If a swap fails with "insufficient output":

1. Try slightly higher slippage (0.5% → 1.0%)
2. Check if the token has transfer taxes (some meme tokens have 5–10% tax)
3. Try a smaller amount
4. Wait — price may be moving rapidly

Gas Optimization

Timing

Gas prices fluctuate. For non-urgent swaps:

• Cheapest: Weekends, early UTC morning
• Most expensive: Weekdays during US/EU business hours
• Check: etherscan.io/gastracker or L2-specific dashboards

Chain Selection

| Chain | Typical Swap Cost | Speed | |-------|------------------|-------| | Ethereum L1 | $5–50+ | 12 sec | | Arbitrum | $0.01–0.30 | 2 sec | | Base | $0.01–0.20 | 2 sec | | Polygon | $0.01–0.05 | 2 sec | | BSC | $0.05–0.50 | 3 sec | | Solana | $0.001–0.01 | 0.4 sec |

Recommendation: For routine swaps, use L2s like Arbitrum (where Sperax ecosystem lives) for cents-level gas costs.

Cross-Chain Swaps

When you need to move tokens between chains:

Bridge Options

| Bridge | Supported Chains | Speed | Notes | |--------|-----------------|-------|-------| | Stargate | 15+ chains | 1–5 min | Most reliable for stablecoins | | Across | Ethereum, L2s | 2–10 min | Fast for ETH/USDC | | Hop | Ethereum, L2s | 5–20 min | Established, reliable | | LayerZero/Wormhole | 30+ chains | Varies | Widest chain support |

Best Practices

1. Bridge stablecoins when possible — less slippage risk
2. Check bridge liquidity before large transfers
3. Double-check destination chain — mistakes are irreversible
4. Allow extra time — bridges can be slow during congestion

Common Swap Pitfalls

1. Tax Tokens

Some tokens (especially meme tokens) have built-in transfer taxes:

• 1–10% on every transfer
• Requires higher slippage to account for tax
• Not shown in quoted price

2. Low Liquidity

Signs of low liquidity:

• Large spread between buy/sell price
• >2% price impact on your trade size
• Few liquidity sources on aggregator

3. Front-Running / MEV

Your transaction may get sandwiched (see MEV Protection skill).

Mitigations:

• Low slippage tolerance
• Private transaction submission (Flashbots)
• Limit orders instead of market swaps
• Batch auctions (CowSwap)

4. Approval Issues

Before swapping, you must approve the router to spend your tokens:

• First swap with a token requires an approval transaction
• Consider using exact-amount approvals for security
• See Token Approval Safety skill for details

Swap Checklist

Before every swap:

• [ ] Verify token contract address (not a scam token)
• [ ] Check price impact (2% impact suggests splitting the trade

1. Recommend L2s for small swaps — don't pay Ethereum L1 gas for small trades
2. For large swaps ($10K+) — suggest splitting, using aggregators, and low slippage
3. Cross-chain: bridge stablecoins first, then swap on destination chain
4. Sperax ecosystem users should swap on Arbitrum for lowest costs

Links

• 1inch: https://1inch.io
• CowSwap: https://swap.cow.fi
• Sperax App (Arbitrum): https://app.sperax.io
• Arbiscan Gas: https://arbiscan.io/gastracker

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Sperax
• Source: Sperax/sperax-skills
• License: MIT

Install and usage instructions live in the source repository linked above.