Cross-Chain Bridge Route API
Best cross-chain bridge routes via LI.FI -- 60+ chains, 18+ bridges, fees and time compared. Pay-per-call via x402 (USDC on Base L2) -- no API key, no signup, no rate-limit wall.
Part of the klymax402 marketplace -- 100 x402 micropayment APIs for AI agents, one wallet, USDC on Base.
Quickstart -- MCP
Add to your MCP client config (Claude Desktop, Cursor, ElizaOS, etc.):
{
"mcpServers": {
"bridge-routes": {
"url": "https://bridge-routes.api.klymax402.com/mcp"
}
}
}
Quickstart -- HTTP (x402)
curl "https://bridge-routes.api.klymax402.com/api/route?fromChain=...&toChain=...&token=...&amount=..."
# -> 402 Payment Required, with an x402 payment challenge in the response body
Any x402-aware client (@x402/fetch, x402-agent-tools, ATXP) handles the 402 -> sign -> retry cycle automatically.
Tools
| Tool | Method | Path | Price | Description |
|---|---|---|---|---|
bridge_find_best_route | GET | /api/route | $0.008 | Find the best cross-chain bridge route |
bridge_find_best_route | POST | /api/route | $0.008 | Find the best cross-chain bridge route (POST variant) |
bridge_find_best_route
Use this when you need to bridge tokens between different blockchains. Returns ranked bridge routes with fees and timing in JSON.
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
fromChain | string | yes | Source chain ID (1=Ethereum, 8453=Base, 42161=Arbitrum, 10=Optimism, 137=Polygon, 56=BSC, 43114=Avalanche) |
toChain | string | yes | Destination chain ID (1=Ethereum, 8453=Base, 42161=Arbitrum, 10=Optimism, 137=Polygon, 56=BSC, 43114=Avalanche) |
token | string | yes | Token symbol to bridge (e.g. USDC, USDT, ETH, WETH) |
amount | string | yes | Amount in smallest unit (e.g. 1000000 for 1 USDC with 6 decimals, 1000000000000000000 for 1 ETH) |
toToken | string | no | Destination token symbol if different from source (optional, defaults to same as token) |
Returns
routes-- array of bridge options ranked by best valuebridgeProvider-- which bridge protocol (Stargate, Across, Hop, Connext, etc.)estimatedTime-- expected bridge completion time in secondsfee-- total bridging fee in USDamountReceived-- expected output amount on destination chainsteps-- detailed step-by-step route (approve, bridge, swap if needed)
Example response:
{"routes":[{"bridgeProvider":"Stargate","estimatedTime":60,"fee":0.85,"amountReceived":"999.15","steps":["approve USDC","bridge via Stargate"]}],"fromChain":"Ethereum","toChain":"Base","token":"USDC"}
When to use: moving assets cross-chain to find the cheapest and fastest bridge. Essential for multi-chain portfolio management.
Not for: gas prices (use gas_get_current_price).
bridge_find_best_route
Use this when you need to bridge tokens between different blockchains. Returns ranked bridge routes with fees and timing in JSON. POST variant of bridge_find_best_route -- same params passed as JSON body instead of query string.
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
fromChain | string | yes | Source chain ID (1=Ethereum, 8453=Base, 42161=Arbitrum, 10=Optimism, 137=Polygon, 56=BSC, 43114=Avalanche) |
toChain | string | yes | Destination chain ID (1=Ethereum, 8453=Base, 42161=Arbitrum, 10=Optimism, 137=Polygon, 56=BSC, 43114=Avalanche) |
token | string | yes | Token symbol to bridge (e.g. USDC, USDT, ETH, WETH) |
amount | string | yes | Amount in smallest unit (e.g. 1000000 for 1 USDC with 6 decimals, 1000000000000000000 for 1 ETH) |
toToken | string | no | Destination token symbol if different from source (optional, defaults to same as token) |
Returns
routes-- array of bridge options ranked by best valuebridgeProvider-- which bridge protocol (Stargate, Across, Hop, Connext, etc.)estimatedTime-- expected bridge completion time in secondsfee-- total bridging fee in USDamountReceived-- expected output amount on destination chainsteps-- detailed step-by-step route (approve, bridge, swap if needed)
Example response:
{"routes":[{"bridgeProvider":"Stargate","estimatedTime":60,"fee":0.85,"amountReceived":"999.15","steps":["approve USDC","bridge via Stargate"]}],"fromChain":"Ethereum","toChain":"Base","token":"USDC"}
When to use: moving assets cross-chain to find the cheapest and fastest bridge. Essential for multi-chain portfolio management.
Not for: gas prices (use gas_get_current_price).
Example agent prompts
- "Bridge tokens between different blockchains"
- "Bridge tokens between different blockchains"
Payment
- Protocol: x402 -- HTTP-native pay-per-call, no signup, no API key
- Network: Base L2 (
eip155:8453) - Asset: USDC
- Facilitator: Coinbase CDP (primary), PayAI (fallback)
- Also reachable via ATXP (OAuth-wrapped x402, RFC 9728 protected-resource metadata)
Part of klymax402
100 x402 micropayment APIs for AI agents -- one wallet, USDC on Base, zero signup.
- Catalog: https://klymax402.com/llms.txt
- Full API reference: https://klymax402.com/llms-full.txt
- Live stats: https://klymax402.com/stats
License
MIT