Spot cross-exchange arbitrage:
one token, different prices across CEX

The same coin trades in parallel on dozens of centralised exchanges — and the prices on them at any given moment almost never agree. Each exchange runs its own orderbook, its own set of market-makers, its own reaction speed to news. Cross-exchange arbitrage is earning on that gap: buy cheap where the price is lower, move the asset to the exchange with the higher price, sell.

Why prices diverge between exchanges

Prices don't equalise instantly because of a fundamental asymmetry: to close the gap, someone has to physically move the asset from one exchange to another, and that takes minutes. In those minutes, different things happen on different exchanges — one reacts to news first, the other lags. One market-maker pulled the level, another stayed. On large exchanges with deep liquidity, a spread against another exchange closes quickly; on thin ones, it can persist for hours.

To understand which spread is actually worth taking, you need to understand the mechanics of both sides and where the costs accumulate.

Buy and sell side: a market order walks the book

On an exchange, a trade fills through orderbook levels top down: a market order takes whatever sits at the best ask (for a buy) or the best bid (for a sell), then the next level, and so on — until the requested volume is filled. The bigger your trade relative to book depth, the worse the effective price you get above best. Each such trade pays a taker fee, typically 0.05–0.1% of volume. Across both sides of the round-trip it's roughly 0.2% on exchange fees alone.

The 'bridge' between exchanges: the blockchain network

To move the asset you just bought from one exchange to another, you initiate a withdrawal to the receiving exchange's deposit address: submit → source exchange confirms → on-chain transaction → destination exchange detects the deposit. This takes anywhere from seconds (Solana, BSC, Base) to 30+ minutes (Ethereum during load). The exchange charges a fixed withdrawal fee — from $0.20 (Solana) to $5–30 (Ethereum tokens).

Full cost list on a typical trade

Each trade pays, in total:

• Taker fee on the buy-side exchange (~0.1%)
• Taker fee on the sell-side exchange (~0.1%)
• Withdrawal fee from the source exchange (fixed, network-dependent)
• Slippage on the buy-side book (worse for thinner books and larger trades)
• Slippage on the sell-side book (same)
• Price drift during the transfer (seconds to tens of minutes)

Two hard thresholds follow: a spread below ~0.6% on liquid majors (BTC, ETH, USDT) or below ~1.5% on alts structurally doesn't clear at a typical $1k size. And a trade volume more than ~1–2% above book depth starts losing more to slippage than the spread provides.

The algorithm is the same for any direction. Steps grouped into three phases: Prep (filter + validate), Execute (buy → transfer → sell), and Close (log).

Step by step — a realistic cross-exchange trade: 4.2% gross spread on PEPE between Bybit (cheaper) and KuCoin (richer), $1,000 USDT notional, Solana for the transfer (PEPE-SOL variant, fast). Numbers are typical for a mid-active session on a memecoin.

The biggest leaks are slippage on the thin sides and price drift during transfer. On Solana the transfer takes ~30 seconds, so drift is minimal. If the route had gone through Ethereum (5–10 minutes confirmation + $5–15 gas), the headline 4.2% would have netted out to 1–2% after all the deductions, and on a volatile alt — sometimes zero.

If the withdrawal had been closed on Bybit (happens after a network upgrade) — the trade couldn't have started. If a memo had been required on the chosen network and forgotten — the tokens would have landed at the general deposit address with no owner attribution. That's why the checks at steps 02–03 matter.

Cross-exchange arbitrage is a daily flow of small trades plus rare big windows on news or listings. Most of the time — typical spreads of 1–3% on alts that close in minutes; during sharp moves (news, listings, panic, kimchi premium) — tens of percent open for N minutes or longer. There's no honest way to quote alerts-per-day or monthly P&L — it depends on market conditions, the tokens and exchanges you focus on, your reaction speed, and your trade size.

What drives results

Spreads widen during volatile sessions — US market open, news reactions, memecoin pump sessions, exchange-specific events (planned maintenance, incidents). Quiet weekends produce few opportunities; high-volatility weeks produce many. The same alert will deliver different results to two traders depending on how fast they run through checklist 01–03 and how cleanly they execute both legs.

What's math, not luck

Trade costs are made of four components: taker fee on the buy side (~0.1%), taker fee on the sell side (~0.1%), withdrawal fee (fixed), slippage on both sides. Sometimes price movement during the transfer gets added.

That gives two hard rules:

• A spread below ~0.6% on majors or ~1.5% on alts is structurally unprofitable. No matter how attractive the ticker.
• Trade volume above ~1% of book depth will eat itself in slippage before the trade reaches the second side.

How cross-exchange differs from neighbouring strategies

Unlike CEX-DEX, there's no on-chain pool and no AMM-curve slippage — both books run on the same mechanics. Unlike cross-chain DEX-DEX, there's no bridge and no bridge-hack risk. But you carry the standard exchange risk: a halted withdrawal = funds locked until they decide to reopen it.