> For the complete documentation index, see [llms.txt](https://docs.aqua.network/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.aqua.network/ecosystem-overview/stellar-essentials.md).

# Stellar essentials

Aquarius is built on the Stellar network and its Soroban smart contract platform. This page collects the Stellar basics you'll run into while using Aquarius — trustlines, reserves, fees, and the native XLM token.

### What is Stellar?

[Stellar](https://www.stellar.org/) is a decentralized, public blockchain focused on currencies and payments. It is fast, cost-effective, and energy-efficient, and it enables the creation, transfer, and trading of digital representations of all types of assets — dollars, bitcoin, or virtually anything else. Assets issued by **anchors** (regulated entities that connect Stellar to traditional finance) can be redeemed for their real-world counterparts.

### What is Soroban?

[Soroban](https://developers.stellar.org/docs/smart-contracts) is the smart contracts platform on the Stellar network. Contracts are small programs written in Rust and compiled to WebAssembly for deployment. Aquarius uses Soroban to power its AMMs and other products in the ecosystem.

### Lumens (XLM) and network fees

The **lumen (XLM)** is Stellar's native token. Every account needs a small amount of XLM to exist on the network, create trustlines, and pay transaction fees. Fees start at 0.00001 XLM per operation; during rare surges of network activity, transactions offering higher maximum fees are processed first — the network only ever charges what is required.

### Trustlines

When you hold an issued asset on Stellar, you hold credit from its issuer — and your account must explicitly opt in to each asset by creating a **trustline**. Trustlines protect you from receiving random, unwanted assets.

You will meet trustlines constantly on Aquarius: an **AQUA trustline is required to receive any rewards**, bribes arrive only for assets you hold trustlines to, and ICE tokens are delivered via trustlines set up by the locker.

### Network reserves

Your wallet locks small amounts of XLM as reserves while you use Stellar and Aquarius features:

* An active account reserves 1 XLM
* Each trustline reserves 0.5 XLM
* Each order book offer reserves 0.5 XLM
* Each additional signer reserves 0.5 XLM
* Each claimable balance for Aquarius voting & governance reserves 1 XLM
* Each claimable balance created by the AQUA locker reserves 0.5 XLM

Reserved XLM returns to your balance when you close trustlines, claim back balances, fill or cancel orders, or remove signers. Keep some spare XLM in your wallet so reserves never block you from voting, locking, or placing orders.

### Claimable balances

Claimable balances are the Stellar feature Aquarius voting and locking are built on: a payment split into a "send" and a "claim" part, with time conditions attached. When you vote or lock AQUA, your tokens sit in a claimable balance — on-chain, reclaimable only by you once the lock period ends. Wallets display these as pending payments.

For the full mechanics, see the [Stellar documentation on claimable balances](https://developers.stellar.org/docs/learn/encyclopedia/transactions-specialized/claimable-balances).