FewToken Integration

Ring Swap (v2) keeps compatibility with v2-style AMM integration patterns while introducing Few Protocol as a wrapping layer.

Integration Overview

To integrate Ring Swap (v2) for swap and liquidity flows, replace your existing v2-style integration points with Ring deployments:

• Ring Swap Factory
• Ring Swap Pair Init Code
• Ring Swap Router
• Universal Router

Key Difference: Few Protocol Wrapping

Few Protocol wraps original ERC-20 tokens into FewToken.

Ring's native swap system, Ring Swap (v2), uses wrapped assets in pools and routes.

When integrating:

• quote prices with FewToken addresses
• construct swap paths with FewToken addresses
• resolve wrapped token addresses via FewFactory

FewToken Address Resolution

Verify FewFactory onchain

Supported FewToken identity must resolve through the published FewFactory for the selected chain.

For Ring integrations, a FewToken is supported only when FewFactory.getWrappedToken(underlying) returns that wrapper address. Token name, symbol, a token() method, or the existence of a pool do not define whether an address is a supported FewToken.

Integration rule

For each chain, read the published FewFactory address from the Deployments page, then verify its bytecode, core() reference, and chain ID onchain.

When your code starts from an original ERC-20, resolve the FewToken yourself:

address wrapper = IFewFactory(fewFactory).getWrappedToken(underlying);
require(wrapper != address(0), "no FewToken for token");

When your code receives a wrapper from an external source, validate it before using it in routing, wrapping, or approval logic:

function _assertCanonicalFewToken(address underlying, address wrapper) internal view {
    address expected = IFewFactory(fewFactory).getWrappedToken(underlying);
    require(expected != address(0), "no FewToken for token");
    require(expected == wrapper, "non-canonical FewToken");
}

Supported FewToken addresses are resolved through FewFactory. The following fields are display or discovery data only:

• symbol() / name()
• a token() method
• a fw or Few Wrapped prefix
• whether a RingSwap-style pool exists
• whether a quote or route looks profitable

Approval spender selection

ERC-20 approvals grant transfer permission to the spender. Select the spender from the integration path you are using, not from arbitrary route or pool metadata.

Flow	Token being approved	Spender
Ring Swap Router swap or add liquidity	Original ERC-20 input	The selected Ring Swap Router
Manual wrap	Original ERC-20 input	The FewToken returned by FewFactory.getWrappedToken(underlying)
Universal Router with Permit2	Original ERC-20 input	Permit2 for the ERC-20 allowance, then the selected Universal Router in the bounded Permit2 authorization
Remove liquidity	Pair LP token	The selected Ring Swap Router, or the same router in the LP permit

Prefer exact amounts and short expiries. Clear temporary allowances when the token and flow support it. Validate every spender against the selected deployment and flow. A Pair, Factory, FewFactory, hook, quote target, or token-list entry is not an approval spender by default.

SDK derivation is a convenience, not an authorization check. Compare its result with the deployed FewFactory. External FewToken-looking addresses are unsupported unless they pass the same onchain check.

Supply and backing boundary

The reviewed FewToken source includes both escrow-backed wrap and role-controlled mint. Privileged minting does not itself transfer the original token into the wrapper. The current Core role holders, pause state, underlying balance, supply, and issuance history must be checked onchain before an integration assumes redemption capacity.

FewToken burn() destroys the caller's FewToken without transferring the original asset. Use unwrap() or unwrapTo() for redemption. See Few Protocol and FewToken for role, pause, raw-unit, and nonstandard-token details.

Important note

Ring Swap (v2) is a native Ring product line. The v2 label describes the compatible AMM design; it is not part of a public Ring product-version ladder.

If you are integrating with v4-related workflows elsewhere in these docs, that should generally be understood as FewToken integration with Uniswap v4, not as a separate native v4 protocol.

Swap Path Example

If your intended route is:

[tokenA, USDC, tokenB]

Use this path for Ring Swap:

[fwTokenA, fwUSDC, fwTokenB]

fwTokenX means the FewToken mapped from original token tokenX.