Decentralised exchanges, explained
Every exchange we list on this site is an AUSTRAC-registered business. A decentralised exchange (DEX) is something different: not a company but a protocol — software running on a blockchain that matches trades directly between users' wallets, with no operator holding your money. That removes some risks and adds others. Here's how they work, who's biggest, and what the rules look like from Australia.
The largest DEXs by trading volume
| # | Protocol | 24h volume | 7-day volume | Blockchains |
|---|---|---|---|---|
| 1 | Uniswap | US$1.91B | US$17.23B | 47 |
| 2 | PancakeSwap | US$1.24B | US$7.10B | 12 |
| 3 | pump.fun | US$764M | US$6.02B | 4 |
| 4 | GMGN | US$740M | US$2.00B | 10 |
| 5 | Kalshi | US$434M | US$2.90B | 1 |
| 6 | Aerodrome | US$327M | US$2.92B | 1 |
| 7 | BisonFi | US$252M | US$1.30B | 1 |
| 8 | Metric | US$219M | US$1.71B | 10 |
| 9 | Pons | US$161M | US$826M | 1 |
| 10 | Polymarket US | US$145M | US$864M | 2 |
Volumes in USD (DEX trading is global) · updated daily · data by DefiLlama. Listing here is information, not endorsement — none of these protocols are AUSTRAC-registered.
How a DEX actually works
Most DEXs don't match buyers with sellers at all. They use an automated market maker (AMM): a smart contract holding a pool of two tokens, priced by a formula. Trade against the pool and the formula moves the price; the people who deposited the tokens (liquidity providers) earn the pool's fees in exchange for taking the risk. That one design choice explains almost everything about DEXs — the good and the bad:
No order book, no waiting for a matching buyer — the pool always quotes a price, 24/7, for any token someone has pooled. That's why brand-new tokens can trade instantly… and why scam tokens can too.
The classic rule keeps the product of the two token balances constant — buy one side and its price rises along a curve. Big orders in small pools move the price a lot: that's slippage, and it's the real cost of trading thin markets.
Each swap pays a small pool fee (commonly ~0.3%) to liquidity providers, plus the blockchain's own gas fee. On Ethereum mainnet, gas alone can dwarf the trade for small amounts — one reason volume lives on cheaper chains.
The risk ledger — what actually goes wrong
Fake and honeypot tokens
Anyone can create a token named anything and pool it. Lookalike tickers, tokens you can buy but never sell ("honeypots"), and rug-pulls where the creator drains the pool are everyday events, not rarities. Verify contract addresses from the project's official channels, always.
Malicious approvals
Interacting with a DEX means signing token approvals. A malicious site can request an approval that lets it move your tokens forever after. Read every signature, cap approval amounts, and periodically revoke old ones (wallets like Rabby surface this).
Impermanent loss (for LPs)
Providing liquidity isn't passive income — if the two pooled tokens diverge in price, you end up worth less than if you'd simply held them. Fees may or may not cover that gap. Understand it before pooling a dollar.
MEV and sandwich attacks
Your pending trade is visible before it confirms, and bots can trade around it — buying just before you and selling just after, worsening your price. Setting tight slippage tolerance is the basic defence.
Smart-contract failure
The contract is the exchange. A bug or exploit can drain pools instantly and irreversibly — it has happened to audited, blue-chip protocols. There is no compensation scheme; audits reduce risk, they don't retire it.
The bridge problem
Moving assets between chains uses bridges — historically the single most-hacked component in all of crypto. If a strategy requires bridging, that step is often the riskiest part of it.
If you're going to try one anyway
- 1 Start from a registered exchange
Convert AUD on an AUSTRAC-registered platform (our exchange list), then move only your experiment budget to a self-custody wallet. The vault stays behind.
- 2 Use a dedicated hot wallet
A separate wallet for DEX activity — ideally one with transaction simulation like Rabby — so an approval mistake can never touch your main holdings.
- 3 Bookmark the official URL
Phishing clones of major DEXs rank in search ads. Get the URL from the project's verified channels once, bookmark it, and never arrive via a search result or a DM.
- 4 Trade small, check everything
Verify the token's contract address, start with a trivial amount, set slippage deliberately, and review approvals monthly. Every DEX swap is also a CGT event — keep your tax software connected.
DEX vs a regulated Australian exchange
| Registered exchange (e.g. Swyftx) | DEX (e.g. Uniswap) | |
|---|---|---|
| Who holds your crypto | The exchange, until you withdraw | You — trades run from your own wallet |
| Account & ID checks | Sign-up + KYC identity verification | None — connect a wallet and trade |
| Paying with AUD | PayID, Osko, bank transfer, card | No — crypto only; you need coins first |
| What you can trade | A curated list (dozens–hundreds) | Almost any token, including scams |
| If something goes wrong | Support desk, AUSTRAC-registered entity, AFSL regime from 2027 | No company, no support, no recourse |
| Typical costs | Spread + trading fee | Pool fee + network gas + slippage |
What Australians should know first
DEXs are not AUSTRAC-registered and won't hold an AFSL when licensing becomes mandatory for Australian platforms in April 2027. There is no company to complain to, no dispute scheme, and no compensation if a smart contract is exploited. See how Australian regulation works.
Every DEX swap is a CGT event, and heavy DEX use multiplies taxable transactions fast. Wallet-based activity is increasingly visible to data-matching. Tax software that reads wallet addresses is near-essential.
Using a DEX means holding your own keys — which is a skill, not a default. Fake tokens, approval-draining contracts and phishing sites are the common failure modes. Start with our wallet lesson and scams & safety.
FAQ
Are DEXs legal to use in Australia?
Using one is not illegal. But the protocols themselves are not AUSTRAC-registered businesses, sit outside Australia’s consumer-protection framework, and will not be covered by the AFSL licensing regime that applies to Australian platforms from April 2027. You are on your own in a way that is not true on a registered exchange.
Do I still pay tax on DEX trades?
Yes — completely. Every swap on a DEX is a CGT disposal event in the ATO’s eyes, exactly like selling on a regular exchange, and the ATO’s data-matching increasingly covers on-chain activity. DEX trading usually creates more taxable events, not fewer. See our tax hub.
Can I buy crypto with Australian dollars on a DEX?
No. DEXs only trade crypto for crypto. Practically, Australians start on an AUSTRAC-registered exchange to convert AUD into crypto, then move funds to a self-custody wallet if they want to use a DEX.
Why do people use them at all?
Access to tokens that never list on regulated exchanges, no account or ID requirements, and self-custody — your coins never sit with a company that could freeze withdrawals or collapse. The trade-off is that every protection a regulated exchange provides disappears.
General information only, not financial advice. DEXs carry material risks — smart-contract failure, scam tokens and irreversible mistakes — and losses are typically unrecoverable.