Glossary

An address is where a payment goes. Bitcoin addresses often start with bc1, Ethereum addresses with 0x, and Solana addresses are long strings of letters and numbers.

The same 0x address can exist on Ethereum, Arbitrum, Base and other similar networks. That is convenient, but it means the address alone does not tell you which network the coins will arrive on. Always check the network too.

Tip: copy and paste addresses, never type them. Then compare the first and last few characters. Some malware swaps the address in your clipboard for the attacker's.

A blockchain is a ledger, a list of balances and payments, that thousands of computers keep in sync. New entries are added in batches called blocks. Once a block is accepted, changing it later is extremely hard.

Each blockchain is its own closed world. Bitcoin keeps a record of BTC, Solana keeps a record of SOL and Solana tokens, Ethereum keeps its own. None of them can see the others. That is the whole reason bridges and cross-chain swaps exist.

Practical point: coins never really leave their blockchain. When you "move" BTC to Solana, something else happens: someone holds your BTC and gives you a token on Solana, or you swap BTC for a coin that already lives there.

A centralized exchange is a business. You deposit coins, it credits your account, and you trade on its books. When you withdraw, it sends coins from its own wallets.

Exchanges are a simple way to change networks: deposit BTC on Bitcoin, sell or keep it, then withdraw on another network the exchange supports. You usually need an account with identity checks.

Risk: while coins are on the exchange, they are the exchange's to control. Withdrawals can be paused. Also check that the network you pick for deposit matches the one you send from, and include a memo when asked.

When your transaction is included in a block, it has one confirmation. Each block after that adds another. Bridges and exchanges wait for a set number before they act, so they are sure the payment will not disappear.

This waiting is the main reason Bitcoin transfers are slow. Bitcoin makes a block about every 10 minutes, so waiting for 1 to 3 blocks takes 10 to 30 minutes. Monero often needs 10 blocks, about 20 minutes. Solana confirms in seconds.

Tip: if a transfer looks stuck, check your transaction on a block explorer. If it is still waiting for confirmations, there is nothing to fix. It just needs time.

A decentralized exchange lets you swap one token for another without creating an account. You connect your wallet, approve the trade, and the contract swaps the tokens. Uniswap on Ethereum and Jupiter on Solana are common examples.

Most DEXs work inside one blockchain. Cross-chain DEXs such as Chainflip and THORChain go further: they take a coin on one network and pay out a different coin on another.

Tip: on a DEX the price depends on how much money sits in the pool. For large trades, check the price impact before you confirm.

EVM stands for Ethereum Virtual Machine, the engine that runs smart contracts on Ethereum. Many other networks copy it: Arbitrum, Base, Optimism, Polygon, BNB Chain, Avalanche and more.

For you this means one wallet like MetaMask and one 0x address work across all of them. Moving between EVM chains is usually the easiest kind of cross-chain transfer.

Non-EVM chains such as Bitcoin, Solana, TON and XRP Ledger work differently. They need a different wallet and address format, and fewer bridges support them.

Finality is when a payment is truly settled. Before that point, a transaction could in rare cases be dropped or replaced. After it, the record is permanent.

Different chains reach finality in different ways. Bitcoin never has a hard line, so services count confirmations instead. Ethereum reaches finality in about 13 minutes. Solana is much faster.

Bridges care about this because paying you before the other side is final could let someone spend the same coins twice. Fast bridges solve it by taking that risk themselves and charging a little for it.

A layer 2 (often called a rollup) processes transactions on its own, bundles them up, and posts the result to Ethereum. You get much lower fees while still leaning on Ethereum for the final record.

Arbitrum, Optimism, Base, zkSync and Linea are all layer 2 networks. They use the same kind of 0x addresses as Ethereum, so the same wallet works on all of them.

Moving from a layer 2 back to Ethereum through the official bridge can take about seven days on some rollups. Fast bridges like Across pay you in minutes or seconds and wait out that delay themselves.

Some networks let you attach a short note to a payment. XRP calls it a destination tag, TON and Cosmos chains call it a memo or comment. Exchanges use it to tell customers apart, because many customers share one deposit address.

Forget the memo, and your coins arrive at the exchange with no name on them. Getting them back usually means a support ticket and can take weeks.

THORChain also uses a memo, but for a different reason: it carries the swap instructions. Front-ends fill it in for you. If a deposit screen shows a memo or tag, copy it exactly.

Each blockchain has its own coin: BTC on Bitcoin, ETH on Ethereum, SOL on Solana. That coin is used to pay the network fee. It is called native because it was born there.

When people say "native BTC", they mean real bitcoin on the Bitcoin network, not a wrapped version sitting on another chain. Native swaps, like the ones Chainflip and THORChain offer, take real coins in and pay real coins out.

Why it matters: a native coin carries only the risks of its own network. A wrapped copy also carries the risk of whoever holds the original.

Every blockchain charges a fee to include your transaction. On Ethereum this is called gas. On Bitcoin it is paid to miners. The fee goes to the network, not to the bridge or the wallet.

Fees change with demand. A Bitcoin transaction might cost under a dollar on a quiet day and much more when the network is busy. Solana fees are usually a fraction of a cent. Ethereum sits in between and can jump during busy hours.

A cross-chain transfer usually involves fees on both networks: one to send and one to deliver. The second is often built into the quote. Check the total you will receive, not just the fee line.

When you create a wallet, it shows you a list of 12 or 24 words. Those words are the master key. Type them into any compatible wallet app and all your coins appear there.

Write them on paper and keep them somewhere safe and offline. Do not store them in screenshots, notes apps or cloud drives.

No real bridge, swap site or support agent will ever ask for your seed phrase. If a site or a "support" person asks for it to "fix a stuck transfer", it is a scam. Close the page.

Self-custody means you hold the keys yourself. Nobody can freeze your coins or lose them for you. Nobody can recover them for you either if you lose your recovery phrase.

Compare it to keeping cash in your own safe versus keeping it in a bank. The safe is fully yours, but if you forget the combination, there is no helpline.

For cross-chain moves, self-custody matters in two places: where you send from and where you receive. A route that pays out to your own wallet keeps you in control. A route that holds your coins in between, even briefly, adds someone you have to trust.

A smart contract is code stored on a blockchain. Once deployed, it runs exactly as written. Think of a vending machine: put in the right coins, and it hands out the snack without a cashier.

Ethereum, Solana and most newer chains support smart contracts. Bitcoin, Monero and some older chains have very limited scripting, which is why they cannot host a normal bridge contract.

Risk: "runs exactly as written" includes the bugs. Several of the biggest bridge losses came from mistakes in contract code. An audit lowers that risk but does not remove it.

A stablecoin is a token meant to hold a steady price, usually one US dollar. USDC is issued by Circle and USDT by Tether. Both say they hold cash and short-term government debt to back every coin.

Stablecoins are often the easiest thing to move between chains. Circle runs its own transfer system (CCTP) that destroys USDC on one chain and creates the same amount on another, so there is no wrapped copy involved.

Risk: a stablecoin is only as good as its backing. Also check which version you hold. Bridged USDC (sometimes shown as USDC.e) is not the same as USDC issued directly by Circle.

A token is an asset created by a program on an existing blockchain. USDC on Ethereum, cbBTC on Base and memecoins on Solana are all tokens. They use the host network but are not its own coin.

The same name can mean very different things on different chains. "USDC" issued by Circle on Solana is the real thing. A token called "USDC" made by a random bridge is only as good as that bridge.

Tip: check the token's contract address on the issuer's official site or a trusted explorer. Scam tokens often copy famous names and logos.

A wallet does not store coins the way a purse stores cash. The coins stay on the blockchain. The wallet stores the secret keys that prove you are allowed to move them.

Wallets are often built for one family of chains. MetaMask works with Ethereum and similar networks, Phantom with Solana, and many Bitcoin wallets only handle BTC. To receive coins on a new network, you need a wallet that supports that network.

Tip: before a cross-chain transfer, open the destination wallet, copy its receiving address for the right network, and keep a small amount of that network's coin there to pay fees later.

An aggregator asks several bridges and exchanges for a quote and shows them side by side. LI.FI, Bungee, Squid and Rango are aggregators. Many wallets build one in.

It saves you from checking five sites yourself. It can also split a route into steps, such as a swap on one chain, a bridge, and a swap on the other.

Keep in mind that the aggregator does not move the money itself. You still rely on whichever bridge it picks, so look at the route details before you confirm. More steps mean more fees and more places to stall.

An atomic swap is a trade with a built-in safety lock. Both people lock coins with the same secret code and a deadline. When one side claims their coins, the code becomes public and lets the other side claim theirs. If nobody claims in time, both get refunds.

It works even on chains with simple scripting, which is why it is one of the few trust-free ways to trade Bitcoin and Monero. Garden Finance uses this kind of lock for BTC.

Downsides: you need someone on the other side, the wait can be long, and you must stay online or use software that claims for you before the deadline.

Blockchains cannot see each other. A bridge connects two of them. It watches for your deposit on one chain and then releases or creates coins for you on the other.

There are a few ways to do this. Some bridges lock your coins and mint a wrapped copy. Some keep pools of money on both sides and pay you from the pool. Some use a fast payer (a solver) who fronts you the money. Circle's CCTP destroys USDC on one side and creates it on the other.

Every bridge asks you to trust something: a company, a group of signers, a validator network or a piece of code. Knowing what that is matters more than the brand name.

Burn and mint works when one issuer controls the token on every chain. You burn (destroy) the token on the source chain, the issuer confirms it, and fresh tokens are created for you on the destination chain.

Circle's CCTP does this for USDC. You end up with real USDC issued by Circle on the new chain, not a wrapped copy. There is no big vault of locked coins for anyone to rob.

The trade-off is that you rely on the issuer. You already trust Circle if you hold USDC, so for USDC this adds very little new risk.

A canonical bridge is the one a network itself provides. Layer 2 networks like Arbitrum, Optimism and Base each have one that connects them to Ethereum.

These bridges are usually the most trusted option for that pair, because they rely on the same security as the network. Tokens bridged this way are often treated as the standard version on the new chain.

The catch is speed. Deposits into a layer 2 are fast, but withdrawals back to Ethereum through an optimistic rollup's official bridge wait for days: about seven on OP Mainnet, about 6.4 on Arbitrum and 5 on Base. Fast bridges exist mainly to skip that wait.

A cross-chain swap is a trade that crosses networks. You send one coin from its home chain and receive a different coin on its home chain. No wrapped token stays in your hands.

Chainflip, THORChain and NEAR Intents do this for Bitcoin. You send BTC to a deposit address, and SOL or USDC lands in your Solana wallet, usually within 10 to 40 minutes.

This is often the simplest choice if you do not need to keep BTC exposure. The cost is built into the exchange rate, so compare what you receive across a couple of providers.

With an intent, you do not tell the system each step. You say: I give this, I want that, on this chain. Then solvers compete to fill your order.

It works a bit like ordering a taxi through an app. You set the destination and price, and a driver who accepts takes care of the route. Across, deBridge, Relay and NEAR Intents use this model.

The benefit is speed: you are often paid in seconds, because the solver uses its own money and waits for the slow part later. If no solver takes your order, it usually expires and your funds are returned.

A liquidity bridge does not create new tokens. It keeps a stock of, say, USDC on Ethereum and on Arbitrum. You add USDC to the Ethereum pool, and the bridge pays you USDC from the Arbitrum pool.

Stargate and Synapse work this way. You receive a normal token on the new chain, not a special bridge version.

Limits: the bridge can only pay what the pool holds. Large transfers can drain a pool or get a worse rate. The pools are also a target for hackers, so the security of the bridge contracts matters.

With lock and mint, you send coins into a vault on chain A. The bridge then creates the same amount of wrapped tokens on chain B. To go back, you return the wrapped tokens, they are destroyed, and the original coins are unlocked.

This is how most wrapped bitcoin works. The vault might be run by a company, a group of signers, or a smart contract.

Risk: all the real coins sit in one place. If the vault is hacked or the keys are stolen, every wrapped token loses its backing at once. Many of the largest crypto hacks hit exactly these vaults.

A messaging protocol is the plumbing under many bridges. It lets a contract on one chain say "this deposit happened" to a contract on another chain, in a way the second chain can trust.

Wormhole, LayerZero, Axelar and Hyperlane are messaging protocols. Each uses a different group to check messages: Wormhole uses a set of 19 Guardians, Axelar a validator network, LayerZero and Hyperlane let each app choose its own checkers.

If you use a token that travels over one of these, you are trusting that group. A false message could create tokens out of nothing, which is what happened in the 2022 Wormhole hack.

A relayer moves information between chains. It sees an event on chain A, such as your deposit, and submits a transaction on chain B so the bridge can act on it.

In Across, the relayer does more: it pays you on the destination chain from its own funds and is repaid later from a pool on Ethereum. In that role it is very close to what other projects call a solver.

A relayer usually cannot steal your funds on its own. The rules of the bridge decide what counts as valid. A relayer that stops working just slows things down, and others can take over.

A solver (also called a filler or market maker) watches for intent orders. When it sees yours, it sends you the coins on the destination chain right away, using its own money.

Later, once your deposit on the source chain is confirmed, the protocol repays the solver. The solver earns a small fee for fronting the money and taking the risk.

For you this is mostly good news: fast payouts and competitive prices. The thing to watch is size. Very large orders may get fewer offers, or none, if solvers do not have enough funds ready on that chain.

A wrapped token is a stand-in. Someone holds the real coin, and you get a token on another chain that can be swapped back for it. cbBTC on Solana and Base, WBTC on Ethereum and tBTC are all wrapped bitcoin.

Think of a coat-check ticket. The ticket is useful only because the coat is behind the counter. If the counter is robbed, the ticket is worth nothing.

Before you hold a wrapped token, ask who keeps the real coins (Coinbase for cbBTC, BitGo for WBTC, a signer network for tBTC) and how you redeem it. Also check liquidity: a wrapped token that few people trade can be hard to sell at a fair price.

Every network needs its own coin for fees. If you bridge USDC to Solana but have no SOL, you cannot move or swap that USDC.

Many bridges and aggregators offer to send a small amount of the native coin along with your transfer. It is often called gas top-up or refuel. It costs a little extra but saves you a lot of trouble.

Tip: if the option exists and your destination wallet is empty, turn it on. A few dollars of the native coin is usually enough for many transactions.

Liquidity is how easy it is to swap something at a fair price. A coin with deep liquidity has lots of buyers and sellers, or big pools, ready to trade.

Think of selling a car in a big city versus a small village. In the city there are many buyers and you get a fair price fast. In the village you might wait or accept less.

For cross-chain transfers, liquidity decides whether a large amount goes through cleanly. A wrapped token with thin liquidity may be cheap to get but expensive to sell later.

A liquidity pool is money left in a contract so others can trade with it. People who add their coins earn a share of the trading fees.

When you swap, you add one token to the pool and take out the other. The more you take, the more the price moves against you. THORChain pairs every coin with its RUNE token in this way.

For you, the size of the pool matters most. A small pool gives a worse rate on a big trade. Check the price impact on the quote screen.

Price impact is the cost of your trade size. Swapping $100 in a big pool barely moves the price. Swapping $100,000 in a small pool can move it a lot.

Quote screens usually show price impact as a percentage. Under 0.5% is normal for common pairs. Several percent means the pool is too small for your amount.

If the impact is high, split the transfer into smaller parts, try another provider, or use a route through a more liquid coin like USDC.

Some cross-chain swaps ask for a refund address on the chain you are sending from. If the swap cannot be completed, the coins are sent back there.

This matters most when you send from an exchange. Exchange withdrawals come from a shared address that is not yours, so a refund sent there may never reach you. Give your own wallet address instead.

Tip: fill it in even when it is optional. A missing refund address can turn a simple failed swap into a long support case.

Prices move while your transaction is waiting. Slippage is the gap between the quote you saw and the result you got.

Swap apps let you set a slippage limit, such as 0.5% or 1%. If the price moves more than that, the trade is cancelled or refunded instead of completed at a bad rate.

Cross-chain swaps from Bitcoin can take 10 to 40 minutes, so prices have more time to move. A setting that is too tight can cause refunds. One that is too loose can cost you money. The default on a reputable app is usually fine for small amounts.

Many swap services do not show a separate fee. Instead they give you a slightly worse rate than the market. That gap is the spread, and it is how they get paid.

For example, if BTC trades at a price where 1 BTC buys 500 SOL, a service might offer 497 SOL. The missing 3 SOL is the spread.

Tip: the only fair way to compare routes is the final amount you receive. A route with "zero fees" can still cost more than one with a visible fee.

An audit is when security specialists read a project's smart contracts and report problems. Serious bridges publish their audit reports.

Audits help, but they are not a guarantee. They check the code at one moment. Later changes can add new bugs. The 2022 Nomad hack, about $190 million, came from a faulty upgrade that let anyone copy the attack.

Good signs: several audits by known firms, a public bug bounty, and a long history without incidents while holding large amounts.

Some systems work on "innocent until proven guilty". A result is posted, and there is a window for anyone to challenge it. If no valid challenge arrives, it is final.

Optimistic rollups like Arbitrum and Optimism use about seven days for withdrawals to Ethereum through their official bridges. Across uses a shorter window for checking relayer repayments.

You rarely have to wait it out yourself. Fast bridges pay you right away and carry the wait for you. The model does need at least one honest watcher ready to raise a challenge.

A custodian keeps assets for someone else. For wrapped tokens, the custodian holds the real coins that back every token. Coinbase is the custodian for cbBTC and BitGo for WBTC.

A good custodian publishes how much it holds and how to redeem. You still rely on it to stay solvent, honest and able to operate.

Risk: a custodian can freeze funds, follow court orders, or fail. If it does, the wrapped token can lose value even though nothing went wrong on the blockchain.

A peg is a promised price: 1 USDC should be $1, and 1 cbBTC should be worth 1 BTC. A depeg is when the market price drifts away from that.

Small gaps are normal and short. Big ones usually mean people doubt the backing, for example after a bridge hack, or that the token is hard to redeem.

If you hold a wrapped token and it depegs, selling it in a panic locks in the loss. Find out first whether the backing is actually at risk, and whether you can redeem through the issuer.

A light client follows another chain's block headers and checks the proofs itself. It does not download everything, just enough to verify that a transaction really happened.

A bridge using a light client is closer to trustless: it relies on the security of the two chains, not on a group of signers. IBC, the system that connects Cosmos chains, works this way.

Light clients are hard and expensive to build between very different chains, which is why most bridges to Bitcoin or Solana use signer groups instead.

A multisig wallet is like a safe with several locks. No single key holder can open it. A set number of them, say 5 of 9, must agree.

Many bridges keep their vaults in a multisig. That is safer than one key, but only if the keys are truly held by separate people with separate security.

The 2022 Ronin hack, about $600 million, happened when attackers got 5 of the 9 keys. Several of those keys were effectively controlled by one organisation. A multisig is only as strong as how spread out its keys are.

A blockchain only knows what happens on itself. An oracle reports facts from outside: the price of BTC, or that a deposit was made on another chain.

Across uses the UMA oracle to check repayments to its relayers. Claims are accepted unless someone challenges them within a set window.

If an oracle reports something false and nobody catches it, the contracts relying on it will act on bad data. That is why oracle design is part of a bridge's trust model.

With threshold signatures (also called TSS or MPC), the key is split into pieces from the start. Each member holds one piece. When enough of them cooperate, they produce a valid signature. Nobody ever sees the whole key.

This is how Chainflip and THORChain control their vaults on Bitcoin and other chains. Chainflip reports a threshold of 100 of its 150 validators. To the Bitcoin network it looks like a normal single address.

The idea is strong, but the safety still depends on who the members are and how hard it would be to corrupt enough of them.

Before a bridge or DEX can take your tokens on Ethereum-style chains, you sign an approval. It says "this contract may spend up to X of my USDC".

Many apps ask for unlimited approval by default to save you a step next time. If that contract is later hacked, the attacker can drain the approved tokens from your wallet.

Tip: approve only the amount you are sending when your wallet allows it. Use a tool like revoke.cash from time to time to remove old approvals.

Every bridge has a trust model, an answer to "who could lose or steal my money?" It might be one company, a group of key holders, a validator network, or code that checks the other chain directly.

Fewer and better-known parties is not always worse. Coinbase holding cbBTC is one point of trust, but a well-known and regulated one. A large anonymous signer group can be weaker if the members are easy to compromise.

Tip: when you compare routes, look at what you trust and for how long. A swap that pays you in minutes only needs trust for those minutes. A wrapped token needs it for as long as you hold it.

Trustless means no middleman can take your coins, even if they wanted to. The system checks everything itself. Atomic swaps and light-client bridges come close to this.

In practice, very few bridges are fully trustless. Most rely on some group being honest. The term "trust-minimized" is often more accurate.

Be careful with marketing. A site saying "trustless" does not make it so. Ask what happens if the operators disappear or the signers collude. And no design protects you from bugs in its own code.

A validator set is the list of computers, run by different operators, that agree on what happened. In bridges they confirm deposits and approve payouts.

Many networks make validators put up a deposit (a bond or stake) that they lose if they cheat. THORChain node operators bond RUNE, and the system aims to keep the bond worth more than what they could steal.

Questions to ask: how many validators are there, who are they, and how many must collude to steal funds? A set of 150 independent operators is much harder to corrupt than 9 run by a few people.

An attestation is a signed note: "this deposit or burn really happened". The destination chain checks the signature before releasing or minting anything.

With Circle's CCTP, you burn USDC on the source chain, Circle's service signs an attestation, and that attestation is used to mint USDC for you on the destination chain.

An attestation is only as trustworthy as whoever signs it. For CCTP that is Circle. For other bridges it might be a group of guardians or validators.

HyperCore is the part of the Hyperliquid blockchain that runs its exchange. Orders, matching, margin and liquidations all happen on-chain here, not on a private server.

HyperCore and HyperEVM run on the same chain and share the same consensus, called HyperBFT. You can move tokens between them with a transfer inside Hyperliquid, without a bridge.

When a bridge or exchange sends USDC to Hyperliquid, it usually arrives in your HyperCore balance, ready for trading.

HyperEVM lets developers deploy Ethereum-style smart contracts on Hyperliquid. Wallets like MetaMask connect to it as a regular EVM network.

It runs on the same chain as HyperCore and is secured by the same HyperBFT consensus. Network fees on HyperEVM are paid in HYPE.

Tokens sent to Hyperliquid can land either on HyperCore or on HyperEVM, depending on the bridge. Check which side your route delivers to, since the two balances are shown separately.

Jettons are TON’s version of tokens, like ERC-20 on Ethereum. The standard is called TEP-74.

Each holder gets a separate small contract, a jetton wallet, that keeps their balance. Your normal TON address controls it, so you still send and receive with that address.

Every jetton transfer is paid in TON, so keep a little TON in the wallet. When you deposit jettons to an exchange, check whether it asks for a comment (memo). Without it the deposit may not be credited.

An OFT is one token spread over many networks. When you send it, it is burned on the starting network and created on the destination. On the token’s home network the original can instead be locked in a contract, called an adapter.

USDT0 works this way: USDT is locked on Ethereum and USDT0 is created on other networks. Many other tokens are also issued as OFTs.

Because the issuer controls the token on every network, you do not end up with a bridge’s own IOU. You still trust LayerZero and the verifiers the issuer has picked to approve each message.

Zcash has two kinds of addresses. Transparent ones work like Bitcoin and show everything. Shielded ones hide who paid whom and how much.

When you swap ZEC to another chain, the deposit address on the swap side is usually transparent. Sending from a shielded balance keeps your earlier history private, but the amount you send into the swap is visible, and the payout on Solana or Ethereum is fully public.

Tip: some exchanges only credit deposits to transparent addresses. Check before you send from a shielded wallet such as Zashi.

UTXO means "unspent transaction output". Bitcoin, Litecoin, Dogecoin, Cardano and Zcash track money as separate pieces, like notes in a wallet, not as a single number.

When you pay, your wallet picks some pieces, spends them, and sends the change back to you. You usually do not see this, but it explains why fees depend on how many pieces your wallet has to combine.

It also helps explain why UTXO chains are harder to bridge. Their scripting is simple, so they cannot run the kind of contract that a bridge on Ethereum uses.

Monero and shielded Zcash hide balances from the public. A view key is a read-only pass. Whoever has it can see the payments, but cannot move the coins.

It is useful for accounting, for proving a payment to an exchange, or for watch-only wallets.

Treat it as private anyway. Sharing it gives up your privacy for that wallet. It is never needed to make a swap, so do not hand it to a site that asks without a clear reason.