> For the complete documentation index, see [llms.txt](https://fx100.gitbook.io/fx100-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://fx100.gitbook.io/fx100-docs/start-here/what-is-fx100.md).

# What is FX100

The mechanics behind an oracle-priced perpetuals DEX.

FX100 is a perpetual futures DEX on Base. Trades are priced from an oracle rather than matched against an order book, and settled against a single shared USDC liquidity vault.

## Liquidation protection

Every new position gets 15 minutes during which it cannot be liquidated, regardless of where price goes.

This exists because brief wicks, thin-liquidity moments, and oracle noise routinely close positions that would have been solvent a minute later. The window does not remove your liquidation price — it gives you time to react to a move rather than being closed by it.

See [liquidation protection](/fx100-docs/start-here/liquidation-protection.md) for the exact rules, including what happens when the window ends and why adding to a position does not extend it.

## No order book

Your fill price is derived from the oracle price, adjusted by a spread reflecting the size of your order and the direction it pushes the market's overall imbalance.

Consequences worth understanding before you trade:

* Your execution price can be better or worse than the oracle price. The dynamic spread can be positive or negative depending on order size and which way it pushes market skew. See [pricing and execution](/fx100-docs/trading/pricing-and-execution.md).
* Limit orders are not resting book orders. They are triggers: when the oracle reaches your price, the order converts to a market fill. The trigger price is not a cap on the fill price. See [order types](/fx100-docs/trading/order-types.md).
* Execution is immediate and does not depend on another trader taking the other side. Available depth is bounded by the vault, not by a book. See [available liquidity](/fx100-docs/how-the-system-works/available-liquidity.md).

## The vault is your counterparty

Liquidity providers deposit USDC into one unified vault that backs every market on FX100. That vault takes the other side of every trade. When you profit, the vault pays you. When you lose, the vault collects.

This is also the structural reason liquidations here cannot be hunted — there is no third party earning a bounty for closing your position, and no local order book to wick. See [liquidation](/fx100-docs/how-the-system-works/liquidation.md).

## Isolated margin, non-custodial

Each position is backed only by its own collateral. Losses are contained within the position that produced them, and liquidating one position has no effect on any other. A long and a short on the same asset are two independent positions with separate margin, separate liquidation prices, and separate protection windows.

FX100 is non-custodial. There is no account balance held by the protocol — each position is backed by its own collateral, posted when you open it and returned when you close.

## What FX100 is not

* Not a spot exchange. All markets are perpetual futures.
* Not multi-collateral. USDC is the only collateral and settlement asset at launch.
* Not free of liquidation. Positions can be liquidated once the 15-minute protection window ends. See [liquidation](/fx100-docs/how-the-system-works/liquidation.md).