This article gives an overview of bitcoin transactions and how they are used on memo.

Addresses and Keys

Bitcoin is almost always sent from one address to another. Addresses are unique and are publicly shareable identifiers for secret private keys. When an address receives bitcoin only the holder of the corresponding private key can then spend those funds.

Anyone can create a transaction saying to send bitcoin from one address to another, but that transaction is not valid unless it contains a digital signature using the private key of the sending address, kind of like signing a check. Anyone can verify a signature, but only the holder of the private key can create them. Once a transaction is created and signed, it cannot be modified, otherwise the signature will no longer match.


Every transaction is different, even if it is between the same two addresses and for the same amount as a previous transaction. When a transaction is created and signed it will have an identifier called a transaction hash that is unique.

Transactions are broadcast to a public network called a blockchain. Anyone connected to a blockchain network can listen to all transactions. Most blockchains have websites where you can view activity, called block explorers. Memo uses the Bitcoin Cash blockchain which has many block explorers. The one memo recommends is called Blockchair at

When a transaction is sent you can view it on Blockchair by searching the transaction hash. If you search the transaction hash on Blockchair and it does not show up under the Bitcoin Cash network then there is something wrong with that transaction.

Block Explorers

All activity on memo uses transactions and can be seen on block explorers. For instance, here is a post made by a user:

In the URL you can see the transaction hash for the post. It is a long hexadecimal string of numbers and some letters. In the top right of the post there is an icon with a grid of small boxes that opens a drop-down menu. The "Explore" option takes you to memo's block explorer where you can see details about the transaction that created the post, e.g.:

This page shows which addresses were involved in the transaction along with other information. Every action on memo can be viewed in the block explorer, not just posts. In the drop-down menu there is also a link to Blockchair, which also uses the same transaction hash, e.g.:


Blockchair shows a lot of similar info that the memo block explorer shows. One of those pieces of information is the block that contains the transaction. In the case of the example, it is in block number 718,564. Blocks of transactions are where the blockchain gets its name. New blocks are added to the network approximately every 10 minutes.

When transactions are broadcast to the network miners hold the transaction in memory so they can add it to the next block. Once the block is mined then the transaction becomes "confirmed" and then miners clear transactions from their memory and start collecting new transactions again for the next block.

Each block builds on the next. Every time a new block is found older transactions accumulate another confirmation. If a block explorer says a transaction has 75,000 confirmations, that means there have been 75,000 blocks since the transaction was mined. Each block also has a timestamp so you know when it was mined.

Memo Addresses

Block explorers like Blockchair allow you to browse not just by blocks and transactions, but by addresses too. Memo uses addresses for accounts. Profile have addresses in the URLs, e.g.:

On profile pages there is the same icon with small blocks that has a dropdown with an "Explore" option. The explore link will take you to the memo address explorer transactions page which shows a list of transactions, e.g.:

The dropdown also has a link to the address page on Blockchair which has similar info, e.g.:


One final concept is the network itself. Originally bitcoin was a single network. Starting in 2017 there was a disagreement that caused the network to split in two with different rules. Bitcoin Cash increased the number of transactions allowed in a block. Those blocks were not considered valid by old miners because they contained too many transactions. This caused two separate chains of blocks to be created.

The big-block Bitcoin Cash chain was given the ticker symbol BCH and the legacy chain retained the BTC symbol. Other than a few differences, BCH and BTC work very similarly. Since 2017 there have been multiple other chain splits over other rule changes leading to more networks.

Memo uses the Bitcoin Cash network (BCH) because it allows for enough transactions to handle increased usage. Since BTC and BCH work very similarly people sometimes get confused about which network they are using. Users should be careful when sending or receiving transactions between memo and external wallets that the wallet they are using is for BCH.

That covers the basics of bitcoin transactions and blockchains. With this info users should be able to better troubleshoot issues they encounter. If they send a transaction from an external wallet to memo, or vice-versa, and are unsure about it, the best first step is to check Blockchair. Verify the transaction hash shows up on Blockchair and is using the Bitcoin Cash network. If the transaction is on Blockchair, shows it is on the BCH network, and the addresses are correct then it is almost certainly valid and successful.

For more information visit the FAQ.