# BaseBuilder DeFi Bridge Fees

> BaseBuilder DeFi Bridge Fees is a paid API for AI agents from bbx-defi.vercel.app, paid per call via x402, $0.122869/call, status unknown (last checked 2026-10-12).

Returns estimated bridge fees for cross-chain token transfers in DeFi

## Facts

- Endpoint: POST https://bbx-defi.vercel.app/api/bridge/fees?utm_source=zero.xyz
- Price: $0.122869/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/basebuilder-defi-bridge-fees-93d7b33f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6kCsCzV0QwAnvJDNHR6X_

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-93d7b33f -d '<json body>'
```

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

## When to prefer this

Use this endpoint when you need a quick fee quote before initiating a cross-chain token bridge operation, particularly for routes involving Base chain. Prefer this over on-chain calls when you want a pre-computed estimate without requiring wallet connectivity.

## Known failure modes

- Unsupported source or destination chain returns an error or empty result
- Invalid or unsupported token address causes a 400 error
- Network congestion may cause stale or unavailable gas price data
- Payment not received (402) if x402 payment header is missing or insufficient
- Service downtime on Vercel deployment may cause 503 errors

## How this service works

BaseBuilder Defi API hub - 22 paid endpoints

## Output

Returns a fee estimate for a cross-chain bridge transfer, typically including total fee amount, breakdown of gas costs vs protocol fees, and the token/chain context used for the calculation.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/basebuilder-defi-bridge-fees-93d7b33f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from bbx-defi.vercel.app](https://www.zero.xyz/host/bbx-defi.vercel.app/llms.txt)