Using AXIS

Glossary

Definitions of the terms used in the AXIS documentation, in alphabetical order, with a link to the page that explains each one.

Allowance#

Permission you give the AXIS contract to move up to a set amount of one token from your account, until a given ledger. AXIS uses it to settle fills of your orders and your own trades. See Allowances and your funds.

AMM#

Automated market maker: an exchange where traders swap against a shared pool of tokens priced by a formula, instead of against other traders' orders. AXIS is an orderbook, not an AMM. See What is AXIS.

AXIS API#

The hosted HTTP and WebSocket service. It embeds the indexer and adds quotes, market depth, price candles and a 24-hour ticker. See How AXIS works.

Backing#

What stands behind an order: the smaller of the owner's balance and allowance in the token the order sells, shared by all of the owner's orders selling that token. A fill the backing cannot cover is skipped. See Order backing.

Base and Quote#

The two assets of a market as apps display them, written BASE/QUOTE. Prices are in quote units per one base unit, and amounts are in the base asset. See Base and quote.

Crossfill#

A contract function anyone can call to match an order against opposite orders whose prices cross it. Both owners get at least their own price, and the caller keeps the difference. See Crossed orders and crossfill.

Demo app#

The AXIS app at dex-demo.axis.markets, a trading interface for AXIS on the Stellar Testnet. See Trading with the AXIS app.

Dust#

An amount worth less than one smallest unit of the other asset at the order's price. The contract never stores dust as an order, and a fill that leaves only dust removes the order. See Minimum order value.

Effective depth#

The part of the orderbook that makers can actually deliver, counting only the backed amount of each order. The AXIS API shows effective depth. See Orderbook depth.

Expiration#

An optional time after which an order can no longer be filled. See Expiration.

Fill#

One execution of a single order inside a trade. One transaction can settle at most 20 fills from different makers. Fill is also the contract's name for a market order. See Orders.

Fill-or-Kill#

An order that fills completely within its limit price or fails without moving anything. See Fill-or-Kill.

Footprint#

The list of ledger entries a Stellar smart contract transaction declares it will read or write. Apps fill it in by simulating the transaction before you sign. See Resource limits and costs.

Indexer#

The open-source library that reads AXIS contract events and rebuilds the orderbook, including how much of each order is backed. See How AXIS works and the developer page Indexer.

Keeper#

Anyone who runs routine maintenance calls: requote to refresh cached oracle prices, subsidize to keep oracle access paid, and ExtendFootprintTTL operations to keep the contract's storage alive. See Running a keeper.

Ledger rent#

The fee Stellar charges for keeping smart contract data in the ledger for a period of time. Each new AXIS order pays about 0.041 XLM for 120 days. See Storage rent for new orders.

Limit order#

An order to buy or sell at a set price or better. The part that does not fill right away stays on the book. See Limit orders.

Maker#

The owner of an order on the book. See Makers and takers.

Market#

A pair of assets that can host limit orders. Both directions of the pair share one market. See Markets and prices.

Market order#

An order that fills what is available now within a limit and leaves nothing on the book. The contract calls it Fill. See Market orders.

Nonce#

A number the app picks for each new order. Together with the owner's address it determines the order ID. See Order IDs.

Oracle#

A service that publishes asset prices on-chain. AXIS uses the Reflector oracle to decide which pairs can host limit orders and to check the minimum order value. See What the oracle is used for.

Order ID#

The number that identifies an order, derived from the owner's address and a nonce. IDs are not sequential. See Order IDs.

Requote#

A contract function anyone can call to refresh the cached oracle prices of a market. A cached price is usable for up to 72 hours. See Price freshness.

Router#

Any app, wallet or bot that chooses which orders a trade should fill and passes their IDs to the contract. The AXIS API finds routes for apps that do not run their own. See How AXIS works.

Safety admin#

The account that can pause trading, change a few contract settings and hand its role to another account. It cannot move funds or touch orders. See The safety admin.

Skip#

What the contract does with a listed order it cannot fill: it passes over the order, leaves it unchanged and continues with the rest of the trade. When the reason is that the maker could not settle, the contract publishes a skip event. See When the book changes before your trade lands.

Soroban#

Stellar's smart contract platform. The AXIS contract is a Soroban contract. See What is AXIS.

Stellar Asset Contract#

The built-in smart contract that lets a classic Stellar asset, such as XLM or USDC, be used by smart contracts. AXIS moves classic assets, and their allowances, through their SACs. See Allowances and your funds.

Subsidize#

The contract function that opens a market or extends its oracle price feeds, paid in XRF. See How a market opens.

Swap#

A trade from one asset to another through one or more markets in a single transaction, with a guaranteed minimum output or maximum input. See Swaps across several markets.

Taker#

The trader whose transaction fills orders already on the book. See Makers and takers.

Trustline#

A classic Stellar account's permission to hold an asset other than XLM. Each trustline locks 0.5 XLM of reserve, which is returned when the trustline is removed. See Trustline reserves.

TTL and archival#

TTL (time to live) is how long a smart contract storage entry stays active. A new AXIS order gets about 120 days on mainnet (7 days on Testnet), and updates extend it. When the TTL runs out, the entry is archived and must be restored before it can be used again. See Order lifetime.

XRF#

The utility token of the Reflector oracle. It pays for oracle price feeds and is burned when someone opens or subsidizes a market. See Market listing fee.