> For the complete documentation index, see [llms.txt](https://docs.nubit.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.nubit.org/utxo-bundling/introduction/what-is-utxo-bundling.md).

# What is UTXO Bundling?

<figure><img src="/files/RrfNGHg1RFHIb5c3pvdL" alt=""><figcaption></figcaption></figure>

UTXO Bundling lets you securely reassign the right to spend a group of UTXOs, without ever moving them on-chain. Rather than merging coins, Thunderbolt reassigns control off-chain. Using a cryptographic trick called a key tweak, users can hand over control of coins instantly, without touching the blockchain.

It’s not just batching. It’s not just compression. It’s a delegation system that preserves Bitcoin’s trust model while unlocking speed and scale.