At the time of writing, almost 100MvB worth of transactions has been dumped into the mempool. If you had lower-fee transactions waiting to be confirmed, there's a risk they'll be purged from the global mempool. If that happens, you might have to recreate the transaction, which can be painful, especially if you're using a multi-sig wallet or an offline, air-gapped wallet.

I'll explain how to alleviate this pain.

Getting the raw transaction hexGetting the raw transaction hex

First thing you'll need is the raw transaction hex. It'll allow you to to rebroadcast the transaction later on. Your wallet might have an option to export the transaction hex. If that's your case, you can skip this section. Otherwise, keep reading.

Both options below require having the txid, the id of the transaction.

# Using bitcoin-cli
$ bitcoin-cli getrawtransaction <txid> >my-transaction.hex

# Using curl
$ curl https://blockstream.info/api/tx/<txid>/hex >my-transaction.hex

Alternatively, you can use your day-to-day browser. Just navigate to https://blockstream.info/api/tx/<txid>/hex.

Save this data somewhere safe. You'll need it later on.

Rebroadcasting the transactionRebroadcasting the transaction

If you can't see your transaction in the mempool or in your wallet anymore, it means it has been purged.

To rebroadcast it, you can either:

• Use bitcoin-cli, or
• Use a third-party service

Using bitcoin-cliUsing bitcoin-cli

You can use bitcoin-cli's sendrawtransaction, but there are privacy concerns:

Note that the transaction will be sent unconditionally to all peers, so using this for manual rebroadcast may degrade privacy by leaking the transaction's origin, as nodes will normally not rebroadcast non-wallet transactions already in their mempool.

If you still want to use bitcoin-cli, here's how:

$ xargs bitcoin-cli sendrawtransaction <my-transaction.hex

Using a third-partyUsing a third-party

By using a third-party you don't expose the relationship between your node and your transaction. This is especially interesting when using a VPN to even hide your IP address.

There are two way to use a third-party:

1. Using the cli
2. Using the browser

Using the cliUsing the cli

xargs curl https://blockstream.info/api/tx -X POST --data-raw <my-transaction.hex

Using the browserUsing the browser

Navigate to the URL below, paste in your transaction's raw hex data, and click "Broadcast transcation" (d'oh).

https://blockstream.info/tx/push

What if it says "mempool error: fee too low"?What if it says "mempool error: fee too low"?

If the mempool is full and won't accept your transaction due to it having a low-fee, you can use Replace-By-Fee (RBF) or Child-Pays-For-Parent (CPFP). However, you'll rather just keep waiting until 1sat/vB is enough, just keep your transaction's raw hex data somewhere save and retry rebroadcasting it whenever the mempool is not so full anymore.