DeFi composability

In traditional finance, moving a fund holding into a brokerage account to borrow against it can take forms, phone calls and days. On a public blockchain, a token from one protocol can be used by another in the same transaction, without the two teams ever speaking. That property is composability, and it is why DeFi is often described as money legos.

How it works

Smart contracts on the same chain can call each other freely. If a token follows a shared standard, such as ERC-20 for balances and transfers or ERC-4626 for vaults, any contract that understands the standard can hold it, value it and move it. No partnership, API key or approval is needed; open code and open standards do the integration work. Because that code is public, anyone can also check exactly how one protocol uses another before relying on the combination. Across chains it is harder, and depends on cross-chain messaging such as Chainlink CCIP.

A worked example

One dollar token can travel through a stack of protocols:

• It is supplied to a vault and becomes a vault token that earns a variable yield.
• The vault token is posted in a money market as collateral, and the holder borrows against it.
• Other units of the vault token are split by a yield tokenization protocol into a principal part and a yield part, each with its own market.
• Some of the tokens are paired in a liquidity pool so others can swap in and out.

Each step is a separate protocol, built by a separate team, and each works because the token behaves predictably.

Why it matters

Composability speeds up building: new products are assembled from existing parts instead of written from scratch. It gives a token more uses, which deepens its liquidity. And it lets one person build positions that would need several institutions in traditional finance.

Not every token is equally composable. A token that rebases, charges a fee on each transfer or can be frozen behaves in ways many contracts do not expect, so protocols often refuse it or need special handling for it. Predictable behaviour is what makes a token easy to build on.

Risks and limits

The same links that add uses also pass risks along. A bug in one protocol can hurt every protocol that holds its token. A bad price from one oracle can trigger liquidations several layers away. When a token loses value, every position built on it is hit at once, and forced selling in one market spreads to others. Leverage stacks quietly: borrowing against a token that is itself a claim on borrowed assets multiplies exposure. Composability also inflates headline figures such as TVL, because the same assets are counted at each layer. Before using a token across several protocols, count the layers. Each one adds its own contracts, governance and liquidation rules to the risk you hold.

Tori Finance's integrations include Morpho, a lending protocol, Curve, a protocol for liquidity pools, and Pendle, a yield tokenization protocol. Native cross-chain transfers run through Chainlink CCIP.