The charge. It's the first idea everyone has: Bitcoin is one price on Kraken and a slightly different price on Coinbase, so buy on the cheaper venue, sell on the pricier one, and pocket the difference. Free money. This very site grew out of a crypto-arbitrage bot built on exactly that premise. The bot never made a dollar. Here's the autopsy.
The evidence
We pulled live top-of-book prices on both exchanges and computed the best possible cross-exchange edge — buy at the lower ask, sell at the higher bid — before any costs:
| Coin | Best cross-exchange edge |
|---|---|
| BTC | +0.014% |
| ETH | 0.000% |
| SOL | 0.000% |
| XRP | −0.014% |
| DOGE | −0.006% |
The gaps are essentially zero — a rounding error. Modern exchanges are stitched together by thousands of bots that erase any real gap in milliseconds. By the time a human sees it, it's already gone.
Now the fees
To capture even that sliver you have to take liquidity on both sides — realistically 0.4% to 0.9% round-trip once you count taker fees on each leg. So you're trying to harvest a 0.01% edge with a 0.5%+ cost. This isn't picking up pennies in front of a steamroller. The pennies aren't even there, and the steamroller is.
The verdict
Retail two-exchange arbitrage is a myth that dies on contact with the fee schedule — the same wall that flattens the 15-minute markets. The edge is real and far too small to keep. The one honest version — being the bot that provides the liquidity everyone else pays to take — is a latency-and-capital business, not a free lunch.
That failed bot did leave us something, though: the lesson this entire site is built on. Measure before you believe.