Bitcoin: Watch It Work

A hands-on exploration of Bitcoin using mempool.space
What actually happens when you send bitcoin?
You press Send in your wallet. A few seconds later, your transaction appears as pending. Eventually, it gets confirmed.
But what happened in between?
Where did your transaction go? Who decided which block it would enter? Why did you pay a transaction fee? And what happens if nobody confirms it?
Most Bitcoin explanations begin with cryptography, consensus, or mining. This session takes a different approach.
We’re going to watch Bitcoin work, in real time.
Using ⁠mempool.space, a visual Bitcoin blockchain explorer, we’ll follow transactions, inspect blocks, examine fee markets, and see how miners turn unconfirmed transactions into confirmed ones.
The goal isn’t just to learn how to use a block explorer. It’s to understand what the explorer reveals about how Bitcoin actually operates.
1. Where do Bitcoin transactions go?
Follow transactions entering the mempool and see how they compete for limited block space. Why isn’t there a single global mempool?
2. What’s inside a Bitcoin transaction?
Take apart a real transaction. Trace its inputs and outputs, calculate transaction fees, and understand how bitcoin moves through the UTXO model.
3. Who decides how much you pay?
Watch the fee market in action. Understand sat/vB, fee estimates, and why two transactions sending the same amount of bitcoin might pay very different fees.
4. How does a transaction become part of a block?
Inspect recently mined blocks, identify mining pools, examine block rewards, and understand the incentives behind transaction selection.
5. What happens when transactions get stuck?
Investigate unconfirmed transactions and understand how Replace-by-Fee (RBF) and Child-Pays-for-Parent (CPFP) can help accelerate confirmation.
6. Can you trust what a blockchain explorer tells you?
A blockchain explorer makes Bitcoin observable, but does that mean you’re independently verifying everything?
We’ll discuss what public explorers can reveal about your activity, why different nodes see different mempools, and what changes when you use your own Bitcoin node.
This will be an interactive, browser-based session rather than a conventional presentation.
We’ll navigate mempool.space together, investigate actual Bitcoin transactions, and use what we observe to understand the underlying protocol.
Bring a laptop if you’d like to follow along.
No programming or command-line experience is required. Basic familiarity with Bitcoin transactions and wallets will help.
This meetup is for you if:
You don’t need to be a Bitcoin developer. You do need to be curious about what’s happening beneath your wallet’s interface.
Bitcoin is an open network. You don’t have to take someone’s word for what is happening. You can observe it yourself.