There's a widely held belief that operating a Bitcoin node is a purely altruistic act, with no personal gain, solely in the service of network decentralization. Some consider it a form of duty for bitcoiners to support the system and show their gratitude to Bitcoin.

As we have emphasized in previous chapters, running a node does not provide any direct financial gain. One might therefore think there is no personal benefit in doing so. However, operating your own node brings many individual advantages. To convince you of this, I will present in this chapter all the reasons—both technical and strategic—that should encourage you to install and use your own Bitcoin node.

When wallet software connects to an external node, it transmits its transactions to an infrastructure that is not under your control. This generates obvious risks of surveillance: the operator of the remote node can analyze the details of your transactions, including amounts and frequencies, and, by cross-checking certain metadata (such as IP addresses, times, and locations), potentially associate them with your identity.

Indeed, as pointed out in a previous chapter, wallets don't communicate with the Bitcoin network by magic; they must connect to a node in order to consult balances or broadcast transactions. If you've never set up your own node, this means that your wallet depends on the infrastructure of a third party (usually the company behind the software). This third party, especially if it's a company, may observe, exploit, or even disclose this data: whether for commercial reasons, under legal constraint, or as a result of piracy.

By using your own node, you broadcast your transactions directly to the network, bypassing intermediaries. Provided you secure your node properly (which we'll discuss later) or comply with certain standards, no information is exposed: neither your IP address nor the details of your transactions pass through an entity you don't control. This is a basic prerequisite for preserving your confidentiality on Bitcoin.

For the same reasons mentioned above, wallet software based on a third-party node is vulnerable to censorship risk: the operator of the remote node may refuse to relay certain transactions for various reasons. It may consider them suspicious or contrary to its policy. The transaction may also be blocked if it does not comply with the node's relay rules. Finally, the operator may specifically target your IP address to block the broadcast of your transactions.

Conversely, by using your own node, you ensure the propagation of your transactions within the peer-to-peer network. This means you retain total control over the distribution of your transactions, with no dependence on an intermediary. As long as the transaction complies with the consensus and relay rules of the nodes connected to yours, it will be broadcast on the network and then, provided sufficient fees are included, integrated into a block by a miner. Having your own node guarantees neutral, permission-free confirmation of your transactions.

Without a personal node, you remain dependent on a third party for access to information, such as your address balance, transaction confirmation status, and block validity. This implies implicit trust in the accuracy and integrity of the external node.

Running a full node means you can check all the protocol rules yourself, for every transaction and every block. As a result, the balance displayed by your wallet is not data received from a remote server, but a result calculated locally from a complete copy of the Blockchain, validated block by block. This approach gives full meaning to the bitcoiners' maxim:

Each node that joins the network reinforces Bitcoin's redundancy and resilience. It facilitates the dissemination of information and enables new peers to connect with each other. Without the nodes, the system would simply be inoperable.

As we have seen, Bitcoin's security is not based on decentralization, mining, or cryptography: as with any system, it relies on individuals. More precisely, it depends on the ability of node operators to resist coercion.

What distinguishes decentralized systems like Bitcoin is the distribution of risk among all those involved in their operation. Running your own Bitcoin node means accepting a share of this risk by ensuring the security of your instance; in doing so, you also lighten the burden of risk for other node operators.

So it's not a direct personal benefit: running a node makes you partly responsible for the network's security. Above all, it's a collective benefit, because your involvement helps to spread the risk. In turn, you increase your own ability to use Bitcoin reliably.

Installing a full node is no trivial operation. It involves installing software, understanding basic operation, monitoring synchronization, examining logs in the event of problems, and even using the terminal. This will necessarily lead you to deepen your understanding of the protocol. This is an indirect, but not insignificant advantage.

Acquiring this knowledge strengthens your confidence in the tool and can reduce the risk of errors or exposure to scams. Running your own node also means learning.

An important aspect, often misunderstood, is that operating a node allows you to choose the rules you apply locally. There are two main types of rules:

These are the fundamental rules of the Bitcoin protocol, ensuring the system's integrity and establishing the criteria for validating transactions and blocks. Any transaction that does not comply with these consensus rules can never be included in a valid block. For example, a transaction with an invalid signature on one of its entries will be systematically excluded.

Changing these rules is equivalent to changing the protocol, and therefore the currency (Hard Fork). However, even without trying to modify them, the simple fact of strictly applying the existing rules confers a certain power: if a block violates the rules, the node immediately rejects it.

These are rules specific to each Bitcoin node, which are added to the consensus rules to define the structure of unconfirmed transactions accepted in the Mempool and relayed to peers. Each node configures and applies these rules locally, which explains why they may differ from one node to another. They only apply to unconfirmed transactions: a transaction deemed "non-standard" by a node will only be accepted if it already appears in a valid block. Changing these rules does not exclude the node from the Bitcoin system.

For example, a transaction with no fees is, according to the consensus rules, perfectly valid, but it will be rejected by default according to the Bitcoin Core relay policy, because the minRelayTxFee parameter is set to 0.00001 (in BTC/kB). However, it is possible, on your own node, to lower this threshold to relay transactions with lower fees, or, conversely, to increase the limit, for example, to 2 Sats/vB, to avoid relaying low-fee transactions.

Spinning your own node means asserting: "I validate what I choose to validate, according to the rules I myself have adopted "*. You thus become an actor in the governance of the system, able to reject an evolution that seems unacceptable to you, or to approve an update according to your own criteria.

So we can quickly try to understand how much power you have over the rules thanks to your node. And the extent of this power will depend on the type of rule.

As far as relaying rules are concerned, the essential thing is simply owning a node, regardless of its economic activity. What's at stake here is whether or not you agree to relay certain types of transactions.

If, for example, you believe that transactions with fees of less than 1 sat/vB should be accepted on Bitcoin, you can adjust this rule on your node so that it broadcasts these transactions, thus facilitating their propagation on the network until a miner eventually includes them in a valid block. Essentially, then, it's a question of power over the dissemination of transactions: each node has decision-making power, since agreeing to relay a type of transaction is tantamount to promoting its acceptance on the Bitcoin network. As a result, if you operate several nodes, you have greater influence over the relay policy, as each node has its own connections and areas of impact on the network.

Indeed, having one or more nodes configured with specific relay rules means determining which part of the network accepts to propagate a given type of transaction. Spreading a message in a peer-to-peer graph, as is the case for Bitcoin transactions, follows the logic of percolation theory. Imagine each node as a site that can be active (p = it relays) or inactive (1-p). As soon as the proportion p crosses a critical threshold (p_c), a giant component emerges: the transaction manages to traverse the network and has every chance of reaching a miner. In a network like Bitcoin, where each node maintains an average of 8 outgoing connections, the p_c threshold is generally set at just a few percent, even lower if some nodes have a very large number of connections.

As long as p remains below p_c, a transaction remains confined to isolated pockets and does not reach a miner. As soon as this threshold is exceeded, it spreads almost instantaneously throughout the entire network.

Ultimately, it is always the miners who decide whether or not to include a transaction in a block. However, the nodes intervene upstream by influencing the distribution of transactions: they determine whether or not the miners will be aware of a given transaction. If a transaction is not relayed to the miners, it is obviously impossible for them to include it in a block.

Adding a few more nodes will therefore have only a marginal impact if the network is already in the percolation phase for a given type of transaction, but it can prove decisive as the percolation threshold approaches. Owning or influencing several nodes, especially if they are well-connected, can increase or reduce the value of p and, consequently, indirectly direct the relay rules that determine which transactions are seen and eventually accepted by miners.

When it comes to your node's influence on the consensus rules, its economic weight is, above all, what will be decisive. This is a crucial concept: the value of any currency is directly related to its ability to facilitate exchange. Indeed, if an object is not accepted by anyone in exchange for goods or services, it theoretically has no monetary utility. For example, if no merchant accepts pebbles as a means of payment, they have no use as money. Of course, utility remains a subjective notion on an individual scale, but in a given territory, the greater the number of merchants accepting an object as a means of exchange, the more likely it is that this object has a monetary utility for the people living in this territory.

Let's take the example of a village where many merchants accept gold in exchange for goods: chances are that gold has a monetary utility for the villagers. This indicates that the utility of a currency depends directly on merchants' decisions to accept or reject it.

This concept is crucial for understanding the power dynamics at play in the Bitcoin system. Satoshi makes it clear: Bitcoin is an electronic cash system; in other words, it provides a service that offers a form of currency, Bitcoin (or BTC). When the protocol rules are modified in a way that is not backward compatible (Hard Fork), this amounts to creating a new system and therefore a new currency. The success or failure of this Fork then depends on the size of its economy, which in turn is determined by the number of merchants accepting this new form of currency.

Let's take an example: let's suppose Bitcoin suffers a Hard Fork. There would then be 2 distinct forms of currency: BTC-1 (the original, unchanged version) and BTC-2 (the new currency with different consensus rules). If all the merchants who accepted BTC-1 continue to do so, but reject BTC-2, then the latter will, in theory, have very limited monetary utility. As a user, I would have no interest in keeping and using BTC-2, knowing that no merchant would want it in exchange for goods or services. Conversely, if 50% of merchants choose to accept BTC-2 exclusively and the remaining 50% take only BTC-1, then the utility of BTC-1 will, in theory, have halved. I use the term "in theory" because utility remains subjective at the individual level and depends on a multitude of factors (such as territory and consumption habits) that are difficult to comprehend on a case-by-case basis.

On Bitcoin, the role of "merchant", understood as any entity with a certain economic weight, of course includes businesses (physical stores, online sales sites, service providers, etc.), but also exchange platforms, since they accept Bitcoin in exchange for other currencies, and miners, since they accept Bitcoin via fees in exchange for the service of including a transaction in a block.

As far as consensus rules are concerned, your node allows you to direct your economic activity towards one currency or another. For example, if you have 10 full nodes at home, but no significant economic activity, your influence during a Fork will be almost nil. Conversely, a single node used to manage a chain of 200 stores accepting Bitcoin confers significant economic weight.

So it's not the number of nodes that matters, but the importance of the economic activity they support. What's more, if your economic activity depends on a node you don't control, its owner will decide what currency you use, as long as you remain connected to that node. This is why running and using your own node is particularly important in the context of system governance: