# Blocks and transactions

> What a transaction is, what a block is, and how they fit together — the two core objects you'll see all over this explorer.

Two objects show up everywhere on this explorer: **transactions** and **blocks**. Understanding them makes every other page easier to read.

## Transactions: the instructions

A **transaction** is a signed instruction submitted to the network. The most common kind says "move this much value from this address to that one," but transactions can also create tokens, deploy a contract, or call one.

Every transaction is **signed** by the sender's private key. On QRL that signature is quantum-resistant — [XMSS](/learn/xmss-explained) on Legacy, [ML-DSA-87](/learn/ml-dsa-87-explained) on QRL 2.0 — which is how the network proves the sender really authorised it without ever seeing the private key itself. A transaction typically carries:

- a **from** and **to** address,
- an **amount**,
- a **fee** (paid to the block producer), and
- a **hash** — its unique fingerprint, which you can paste into search.

## Blocks: the batches

The network doesn't confirm transactions one by one; it groups them into **blocks**. A block bundles many transactions and adds:

- a **height** — its sequential position in the chain (block #1, #2, …),
- a **timestamp**,
- the **hash of the previous block** (the link that forms the [chain](/learn/what-is-a-blockchain)), and
- who produced it (a miner on QRL Legacy, a validator on QRL 2.0).

New blocks arrive at a roughly regular cadence. On QRL 2.0, that cadence is anchored to 60-second [slots](/learn/slots-epochs-beacon-chain).

## Confirmations and finality

When your transaction lands in a block, it has one **confirmation**. Each new block built on top adds another. Because rewriting a block means redoing every block after it, more confirmations means the transaction is harder to reverse — effectively permanent once it's deep enough. QRL 2.0's Proof-of-Stake design also adds an explicit notion of **finality** through the [beacon chain](/learn/slots-epochs-beacon-chain).

## What's different between the two chains

- **QRL Legacy** transactions are a fixed set of types (transfers, the mining reward, token and message operations). One transfer can pay multiple recipients at once.
- **QRL 2.0** transactions are EVM-style: simple transfers, plus contract creations and calls, with fees metered in [gas](/learn/gas-and-fees-explained). Validator rewards arrive as separate protocol [withdrawals](/learn/withdrawals-explained), not as ordinary transactions.

## Where to go next

- [Reading a block explorer](/learn/reading-a-block-explorer) — how to navigate these objects here.
- [Wallets, addresses and keys](/learn/wallets-addresses-and-keys) — who sends and receives.
- [Gas and fees explained](/learn/gas-and-fees-explained) — what the fee pays for.