Textile FX

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Under the hood ​

One page on the technology, for anyone who wants to evaluate Textile FX before moving real volume through it.

Architecture ​

Textile FX is an off-chain order book settled by on-chain contracts. Fillers post prices off-chain; your swap executes them on-chain, and funds land in your wallet in a single transaction.

Fillers sign limit orders off-chain and submit them to the book — and a trader's limit order is the exact same signed primitive, resting in the same book. When you swap, the app matches your order against the whole book and executes the matched orders on-chain through a reactor contract. The How it works page covers the mechanics; this page covers what the pieces are built from.

Audited settlement rails ​

The order book deliberately introduces no new cryptography. Swaps execute through Uniswap's audited contracts, vendored verbatim at pinned commits so they stay exactly as audited:

  • UniswapX LimitOrderReactor (v2.1.0): the contract that validates and executes signed limit orders. The same reactor design that runs Uniswap's intent-based trading.
  • Permit2: Uniswap's signature-based token transfer system, in production across the EVM ecosystem since 2022. Your order signature is an EIP-712 message; nothing moves without it, and each nonce can execute only once.
  • solmate: the battle-tested utility library UniswapX builds on.

A filler's quote is a signed commitment. When your swap matches it, the reactor verifies the signature, pulls the filler's funds through Permit2, and delivers your output, all in the same transaction.

Non-custodial by construction ​

The protocol never holds your funds. A filler funds their own orders from their own wallet, and your tokens move only when your signed swap executes. There is no pooled balance to redirect and no custodian in the middle: the reactor either settles a matched pair atomically, in full, or the transaction reverts and nothing moves.

The order book lives off-chain because posting and replacing quotes should be free and instant. It can't move money on its own; it only relays signed orders that the reactor verifies before executing. The contracts are written in Solidity 0.8.30 on OpenZeppelin v5's audited libraries.

Open source ​

Stitch, the filler bot that quotes the order book, is open source at github.com/textile-protocol/textile-stitch. The order book API is documented in the filler guides.

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