NBXplorer for WindowsUTXO Tracker for HD Wallets

What Is NBXplorer and Who Is It For?

NBXplorer sits in the background of a wallet or payment system. Its job is to watch addresses that belong to a hierarchical deterministic wallet and report which unspent outputs and transactions are associated with them. Applications can then ask the service what they need instead of scanning the blockchain themselves.

The typical audience is a small team building a checkout flow, a bookkeeping tool or a wallet backend. A solo developer testing a Bitcoin integration can also use it on a laptop. Casual users who only want to send and receive coins in a mobile wallet will find it too low-level, because the project does not provide a finished consumer interface.

The scope is deliberately narrow. NBXplorer tracks data and exposes it through an API, and it leaves decisions about invoices, accounting rules and user accounts to the application that uses it. That separation is the reason many developers find it easier to reason about than a larger all-in-one stack.

How UTXO Tracking Works in Practice

Bitcoin does not store balances the way a bank account does. Instead, each payment creates unspent transaction outputs, usually called UTXOs, and a wallet's balance is the sum of the outputs it can still spend. A tracker has to find every output that belongs to a wallet and remember when it is spent.

HD wallets make this harder. A single extended public key, often written as an xpub, can produce a long sequence of addresses. A tracker must know the derivation scheme, meaning the rules that turn the key into addresses, and then scan forward through that sequence. If it scans too little, new payments may be missed. If it scans too much, it wastes time and storage.

This is why the derivation and tracked-source settings matter. Getting them right at the start avoids a later rescan, which can be slow on a busy chain. When you understand this model, the API responses become easier to interpret, because each figure corresponds to a set of outputs rather than a single account entry.

Real-World Use Cases for Merchants and Developers

A shop that accepts Bitcoin needs to know, for each invoice, whether the matching payment has arrived and how many confirmations it has. An application can register the store's extended public key with NBXplorer and poll the API for new outputs. The shop's own software then decides when an order is paid.

Another common case is a bookkeeping or reporting tool. It can read transaction history through the API or, where appropriate, query the documented PostgreSQL schema to build monthly summaries. Developers testing wallet logic can also use the service on a test network setup to check that their address generation matches what the tracker sees.

A third scenario is an internal operations dashboard. A treasury team can monitor a set of watched wallets and be alerted when outputs move. Because NBXplorer is a backend component, the dashboard would still need its own access controls, and the team should avoid exposing the raw API to the public internet.

Supported coins

The project documentation names Bitcoin (BTC) as the chain covered in its current guides. The operator guide includes a section on supported chains, so check it before planning a deployment that needs another network. The contributing guide describes how developers can add support for additional chains.