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

FewFactory is the source of truth

Supported FewToken identity must come from the official FewFactory.

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 official FewFactory address from the Deployments page.

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.

Supported patterns:

• If you use the official Ring Router or Universal Router, approve only the official router or Permit2 address for the chain.
• If you manually wrap, approve only the canonical FewToken returned by FewFactory.getWrappedToken(underlying).
• Prefer exact-amount approvals and clear temporary allowances after use when your flow supports it.
• Use a wrapper address from a pool, quote, route, token list, or subgraph only after the FewFactory check above.

If you use the official Ring SDK helpers and official deployment addresses, your integration should derive the expected FewToken addresses from Ring configuration. External FewToken-looking addresses should be treated as unsupported unless they pass the FewFactory check.

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.