Glossary

Complete glossary of terms used in LX documentation and APIs.

A

Aggregate Signature

A cryptographic signature that combines multiple signatures into one, reducing verification overhead. LX uses BLS aggregate signatures for validator consensus.

All-or-None (AON)

An order condition requiring the entire order quantity to be filled in a single transaction or not at all. See also: Fill or Kill.

Alpha

In consensus, the confidence threshold (typically 0.8 or 80%) required for block finality. Higher alpha values increase security but may slow finality.

API Key

A unique identifier used to authenticate API requests. API keys should be kept secret and never exposed in client-side code.

Arbitrage

The practice of exploiting price differences between markets. LX provides low-latency infrastructure enabling cross-market arbitrage.

Ask

An order to sell an asset at a specified price. The lowest ask price is the best ask. See also: Bid.

Atomic Settlement

A settlement method ensuring all parts of a trade complete together or not at all. Prevents partial execution failures.

B

Backend

The execution engine handling order matching. LX supports multiple backends: Pure Go, C++, GPU/MLX, and FPGA.

Base Asset

The first asset in a trading pair. In BTC-USDT, BTC is the base asset. Also called the base currency.

Best Bid/Best Ask (BBO)

The highest bid price and lowest ask price currently available in the order book. Represents the tightest spread.

Bid

An order to buy an asset at a specified price. The highest bid price is the best bid. See also: Ask.

Block

A unit of data containing transactions that has been validated and added to the blockchain. LX achieves 1ms block finality.

Block Height

The sequential number of a block in the chain, starting from 0 (genesis block).

BLS Signature

Boneh-Lynn-Shacham signature scheme enabling efficient signature aggregation. Used for validator consensus in LX.

B-Tree

A self-balancing tree data structure used for price level storage. Provides O(log n) insert, delete, and search operations.

Byzantine Fault Tolerance (BFT)

The ability of a distributed system to reach consensus despite malicious actors. LX uses K=3 validators for BFT.

C

Cancel

To remove a pending order from the order book before execution.

Chain ID

A unique identifier for a blockchain network. Used to prevent transaction replay across networks. See Networks.

Circular Buffer

A fixed-size data structure that overwrites oldest data when full. Used for zero-copy trade recording in LX.

Clearing

The process of validating and recording trades after execution. Precedes settlement.

Clearinghouse

The entity or system responsible for trade clearing. In LX, an automated smart contract system.

Client Order ID

A unique identifier assigned by the client to track orders. Must be unique per user session.

Consensus

The process by which distributed nodes agree on the state of the ledger. LX uses DAG-based consensus with FPC.

Cross-Chain

Operations spanning multiple blockchain networks. LX supports cross-chain asset transfers via bridges.

D

DAG (Directed Acyclic Graph)

A data structure where blocks can have multiple parents, enabling parallel processing. Core to LX consensus.

Day Order

An order that expires at the end of the trading session if not filled. See Time in Force.

Depth

The number of price levels shown in an order book snapshot. Maximum depth is typically 100 levels.

Deterministic

A property ensuring identical inputs always produce identical outputs. Critical for blockchain state consistency.

Dilithium

A post-quantum cryptographic signature algorithm based on lattice problems. Part of LX quantum-resistant security.

E

Engine

The core matching system that processes orders. See Backend.

Epoch

A defined period in the consensus protocol. Validator sets may change between epochs.

Execution

The process of matching and filling an order. May be partial or complete.

Execution Report

A message confirming order execution details including price, quantity, and fills.

F

Fee

The cost charged for executing a trade. Includes maker fees, taker fees, and network fees.

Fill

A trade that satisfies part or all of an order. Multiple fills may complete one order.

Fill or Kill (FOK)

An order type requiring immediate complete execution or cancellation. No partial fills allowed.

Finality

The point at which a transaction is irreversible. LX achieves 1ms finality for trades.

FIX Protocol

Financial Information eXchange protocol. An industry-standard for electronic trading. Supported for institutional clients.

FPGA

Field-Programmable Gate Array. Hardware accelerator achieving 100M+ orders/sec throughput.

Front-Running

The practice of placing orders ahead of known pending orders. LX implements MEV protection.

G

Gas

The fee unit for computational work on EVM-compatible chains. Not directly applicable to LX native chain.

Gateway

The entry point for client connections. Handles authentication, rate limiting, and request routing.

Genesis Block

The first block in a blockchain (height 0). Contains initial state and configuration.

Good Till Cancelled (GTC)

An order that remains active until filled or explicitly cancelled. Default time-in-force.

gRPC

Google Remote Procedure Call. High-performance binary protocol used for LX API access.

H

Hash

A fixed-size output from a cryptographic hash function. Used for block identification and data integrity.

Hidden Order

An order not visible in the public order book. Only revealed upon execution.

HSM

Hardware Security Module. Secure device for cryptographic key storage. Required for validators.

Hybrid Order

An order combining characteristics of multiple order types.

I

Iceberg Order

An order showing only a portion of total quantity. Replenishes visible size as fills occur.

Immediate or Cancel (IOC)

An order type filling available quantity immediately and cancelling any remainder.

Index Price

A reference price calculated from multiple sources. Used for mark price and liquidations.

Insurance Fund

A reserve fund covering losses from liquidations that exceed collateral.

J

JSON-RPC

A stateless, lightweight remote procedure call protocol using JSON. Primary API protocol for LX.

JWT

JSON Web Token. Used for session authentication after initial API key verification.

K

K-Value

The validator threshold in consensus. K=3 means three validators must agree for finality.

Kyber

A post-quantum key encapsulation mechanism. Used for secure key exchange in QZMQ.

L

Latency

The time delay between request and response. LX targets sub-microsecond matching latency.

Leverage

Trading with borrowed funds. Leverage amplifies both gains and losses.

Limit Order

An order to buy or sell at a specified price or better. Rests in the order book until filled.

Liquidation

Forced closing of a position when margin falls below requirements.

Liquidity

The ease of buying or selling an asset without affecting its price. Higher depth means higher liquidity.

Lock-Free

Data structures that allow concurrent access without mutex locks. Critical for low-latency performance.

Lot Size

The minimum quantity increment for orders. Varies by trading pair.

LUX

The native token of the Lux blockchain network. Used for staking, fees, and governance.

M

Maker

A trader who provides liquidity by placing limit orders. Typically pays lower fees.

Maker Fee

The fee charged to the maker side of a trade. Usually lower than taker fee.

Mark Price

A fair price calculation used for unrealized PnL and liquidations.

Market Data

Real-time information about prices, trades, and order book state.

Market Order

An order to execute immediately at the best available price.

Matching Engine

The core component that pairs buy and sell orders. Heart of the DEX.

MEV

Miner/Maximal Extractable Value. Profit from reordering transactions. LX implements protection.

Mempool

The pool of pending transactions awaiting inclusion in a block.

Modify Order

A request to change price or quantity of an existing order. May lose time priority.

MLX

Apple's Metal-based machine learning acceleration framework. Powers GPU orderbook engine.

N

Nonce

A sequential number ensuring transaction order and preventing replay attacks.

NUMA

Non-Uniform Memory Access. Memory architecture consideration for high-performance systems.

O

Object Pool

A cache of pre-allocated objects for reuse. Reduces garbage collection overhead.

Off-Chain

Operations occurring outside the main blockchain. Order matching in LX is off-chain.

On-Chain

Operations recorded directly on the blockchain. Final settlement in LX is on-chain.

Open Interest

The total number of outstanding derivative contracts.

Open Order

An order currently resting in the order book awaiting execution.

Oracle

A service providing external data to blockchain systems. Used for index prices.

Order Book

The collection of all open orders for a trading pair, organized by price level.

Order ID

A unique identifier assigned by the exchange to track an order.

P

Partial Fill

Execution of only a portion of an order quantity.

Peg Order

An order that tracks a reference price (e.g., best bid minus offset).

Position

The net holding in an asset. Can be long (positive) or short (negative).

Post-Only

A flag ensuring an order only adds liquidity. Rejected if it would immediately match.

Post-Quantum

Cryptographic algorithms resistant to quantum computer attacks. LX supports Dilithium and Kyber.

Price Level

All orders at a specific price point. Organized as FIFO queue.

Price-Time Priority

Matching algorithm prioritizing best price first, then earliest order at same price.

Priority Fee

Additional fee to prioritize transaction inclusion. Higher fees processed first.

Pro-Rata

Allocation method distributing fills proportionally to order size at a price level.

Q

Quantum-Resistant

See Post-Quantum.

Queue Position

An order's place in the time-priority queue at its price level.

Quote Asset

The second asset in a trading pair. In BTC-USDT, USDT is the quote asset.

QZMQ

Quantum-secure ZeroMQ. Secure messaging protocol for validator communication.

R

Rate Limit

Maximum allowed requests per time period. Prevents abuse and ensures fair access.

Reduce-Only

A flag ensuring an order only reduces an existing position.

Reject

Order refused by the system. May be due to validation failure or insufficient funds.

Remaining Size

The unfilled portion of a partially filled order.

Replay Attack

Attempt to reuse a valid transaction on a different network. Prevented by chain ID.

REST API

Representational State Transfer API. HTTP-based interface for LX.

Risk Engine

The component performing pre-trade and post-trade risk checks.

S

Self-Trade Prevention (STP)

Mechanism preventing a user from trading with their own orders.

Settlement

The final transfer of assets between parties after trade clearing.

Shard

A partition of data or processing for horizontal scaling.

Side

The direction of an order: buy or sell.

SIMD

Single Instruction Multiple Data. CPU optimization used in C++ backend.

Slippage

The difference between expected and actual execution price.

Snapshot

A point-in-time capture of order book state.

Spread

The difference between best bid and best ask prices.

Stake

Tokens locked as collateral for validator participation.

State Root

A cryptographic commitment to the entire system state at a block height.

Stop Order

An order triggered when price reaches a specified stop price.

Stop-Limit Order

A stop order that becomes a limit order when triggered.

Symbol

The identifier for a trading pair (e.g., BTC-USDT).

T

Taker

A trader who removes liquidity by matching existing orders.

Taker Fee

The fee charged to the taker side of a trade. Usually higher than maker fee.

Throughput

The number of operations processed per unit time. LX achieves 434M+ orders/sec.

Tick Size

The minimum price increment for orders. Varies by trading pair.

Time in Force (TIF)

The duration an order remains active. Options: GTC, IOC, FOK, DAY.

TLS

Transport Layer Security. Encryption protocol for secure connections.

Trade

A matched transaction between buyer and seller.

Trade ID

A unique identifier for an executed trade.

Trailing Stop

A stop order that adjusts with favorable price movement.

Transaction

A signed request to change blockchain state.

TWAP

Time-Weighted Average Price. An execution algorithm spreading orders over time.

U

Unrealized PnL

Profit or loss on open positions based on mark price.

Uptime

The percentage of time a system is operational. Validators require 99.9% uptime.

V

Validator

A node participating in consensus by validating and proposing blocks.

Volatility

The degree of price variation over time.

Volume

The total quantity traded over a period.

VWAP

Volume-Weighted Average Price. A benchmark calculated from price and volume data.

W

Warp Message

Cross-chain message format in Lux ecosystem. Used for DEX-blockchain communication.

WebSocket

Protocol for real-time bidirectional communication. Used for market data and order updates.

Weight

A validator's influence in consensus, typically proportional to stake.

X

X-Chain

Asset chain in Lux ecosystem. UTXO-based for transfers.

Y

Yield

Return on investment over time. May include trading fees and staking rewards.

Z

Zero-Copy

Memory optimization avoiding data duplication during transfer.

Zero-Knowledge Proof

Cryptographic proof verifying a statement without revealing underlying data.

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See Also

• Error Codes - All error codes
• Order Status - Order lifecycle
• Precision - Tick and lot sizes

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Last updated: 2025-12-11