Orca Crypto
Learn

How a transaction actually works

Four stages, one of which is where almost all the confusion lives.

Updated 2026-08-306 min readBeginner
The short answer

A crypto transaction is a signed instruction broadcast to the network. It waits in a public queue called the mempool, gets picked up by a validator, is included in a block, and then gains confirmations as more blocks are built on top. Once confirmed it cannot be reversed by anyone.

The four stages

  1. Construction

    Your wallet assembles the details: from, to, amount, fee, and a nonce that stops the same transaction being submitted twice.

  2. Signing

    Your private key signs it. The key stays on your device. Only the signature travels.

  3. Broadcast and waiting

    It spreads to nodes and sits in the mempool, publicly visible. Validators generally take the most profitable transactions first. This is where a low fee leaves you stuck.

  4. Inclusion and confirmation

    A validator puts it in a block. Each subsequent block adds a confirmation. On chains with instant finality, one block is enough.

What each status means

StatusWhat it meansWhat to do
PendingSitting in the mempool, not yet includedWait, or resubmit with a higher fee
SuccessIncluded and executed as intendedNothing. It is final
Failed or revertedIncluded in a block but the code rejected itYou still paid gas. Check the reason on the explorer
DroppedRemoved from the mempool without inclusionResubmit. Nothing was charged
Failed does not mean free
A failed transaction still costs gas on most chains. The network did the work of trying, even though the result was rejected. This surprises people, and it is normal.

When a transaction is stuck

You submitted, the fee was too low, and it has been pending for an hour. Two ways out:

  • Speed up. Resubmit the same transaction with the same nonce and a higher fee. Most wallets offer this as a button. The replacement takes priority.
  • Cancel. Send a zero value transaction to yourself with the same nonce and a higher fee. It replaces the stuck one. You pay gas, but nothing else happens.

Because Ethereum processes transactions in nonce order per account, a stuck transaction blocks every later one from the same wallet until it clears. That is why you can suddenly have five pending transactions when only the first one had a problem.

Reading the result

Every transaction has a hash, a unique identifier. Paste it into a block explorer and you can see the sender, recipient, amount, fee paid, block number, and for contract calls a decoded breakdown of exactly what executed.

Learning to read this is genuinely useful. When someone claims they sent you funds, you can check rather than argue. When a swap gives you less than expected, you can see precisely where the difference went.

Common questions

Can I cancel a confirmed transaction?

No. Once it is in a block and confirmed, it is permanent. This is the fundamental difference between crypto and a bank transfer, and it is why sending a small test amount first is worth the extra fee.

Why did my transaction fail but still cost money?

Gas pays for computation attempted, not computation succeeded. Common causes are slippage exceeded, insufficient token allowance, or a contract condition that was not met.

What is a nonce?

A counter for your account, starting at zero and incrementing with each transaction. It enforces order and prevents the same transaction being replayed. If it looks wrong, resetting the account in your wallet settings usually fixes it.

Where to go next

Stuck on this one?

Some things click faster with someone walking you through them live. Orca sessions are one to one, screen shared, and paced for wherever you actually are.