> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tplus.cx/llms.txt
> Use this file to discover all available pages before exploring further.

# Composability

> How Tplus reaches external liquidity and assets: settlements and cross-margining.

Composability lets a Tplus account reach liquidity and assets outside the internal orderbook. Programmable **chains** are reached with [settlements](#settlements); non-programmable **exchanges** with [cross-margining](/funds/cross-margining).

## Settlements

A settlement pulls assets from the global deposit vault, runs an arbitrary onchain interaction — a swap, an LP deposit, a liquidation — and returns assets to the vault, atomically. If any step fails the whole settlement reverts (like a flash loan). No withdrawal is involved, and the clearing engine approves only if the resulting inventory change improves IM surplus.

The main use is clearing exposure. A maker fills a buy order and is now short ETH on Tplus; a settlement pulls USDC from the vault, buys ETH onchain (Uniswap), and returns the ETH to the vault — closing the short in one step, with no warehoused inventory.

Mechanics, margin checks, and integrator details: [Settlement](/funds/settlement).

## Finality and re-orgs

Reaching external chains means dealing with probabilistic finality — the same risk a centralized exchange manages when it credits a deposit before the chain finalizes.

Deposits and withdrawals wait for the chain's [confirmation policy](/funds/deposits#chains-and-confirmation-times), then pass a canonical-block check: events on orphaned blocks are dropped and re-ingested from the canonical chain, so no orphaned event is ever applied. Withdrawals execute onchain only against finalized vault state.

## Cross-margining

An account on an external exchange can count as margin collateral on Tplus, so a maker can quote on Tplus, hedge on the exchange, and have the hedge's offset recognized on the Tplus side. Every supported asset on a cross-margined exchange becomes quotable on Tplus.

Operational details: [Cross-margining](/funds/cross-margining).

## Synchronous making

Sync orders combine a fill with a settlement that clears the exposure in the same atomic operation, so a maker can quote an asset it holds no inventory in: at fill time the underlying is sourced from onchain liquidity. Sync orderbooks are spot-only and limited to the primary sub-account. Each sync order carries a delegated settlement request, signed by the maker and checked by the OMS for signature validity and expiry before matching.

Market makers receive their pending sync-book settlements on the authenticated stream `GET /sync/pending_settlements`; sync orderbooks are created via `POST /sync_book/create`. See the [Trading API](/api-reference/overview).