# BaseBuilder DeFi Bridge Fees

> BaseBuilder DeFi Bridge Fees is a paid API for AI agents from bb-defi.vercel.app, paid per call via x402, $0.122869/call, status unknown (last checked 2026-09-14).

Calculates cross-chain bridge fees for DeFi token transfers via the BaseBuilder DeFi API hub

## Facts

- Endpoint: POST https://bb-defi.vercel.app/api/bridge/fees
- Price: $0.122869/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/basebuilder-defi-bridge-fees-02ca515e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mE7lY4vOjP5ztGoaqHI8Y

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability basebuilder-defi-bridge-fees-02ca515e -d '<json body>'
```

Example prompt: What would the bridge fees be to move 500 USDC from Ethereum mainnet to Base chain right now?

## When to prefer this

Use this endpoint when you need to estimate or display bridge fees before executing a cross-chain DeFi transfer, particularly for routes involving the Base network. Prefer this over generic DEX fee estimators when the user specifically wants cross-chain bridging cost information rather than in-chain swap fees.

## Known failure modes

- Unsupported source or destination chain returns an error or empty result
- Invalid token address or unsupported token pair returns a validation error
- Network congestion may cause stale or unavailable fee quotes
- Payment of $0.122869 USDC required per call via x402 protocol; missing payment returns 402
- Amount too small or too large for bridge route may return out-of-range error

## How this service works

BaseBuilder Defi API hub - 22 paid endpoints

## Output

Returns a fee breakdown for a cross-chain bridge transaction, including estimated gas costs, protocol fees, and total cost in the relevant token and/or USD equivalent for the specified route and amount.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/basebuilder-defi-bridge-fees-02ca515e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from bb-defi.vercel.app](https://www.zero.xyz/host/bb-defi.vercel.app/llms.txt)