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Gas Estimator API

Official registry Other

Multi-chain gas estimation — ETH, Base, Polygon, Arbitrum, BSC. x402 micropayment.

Source code Website Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

Remote (sse)
Claude Code 
claude mcp add --transport sse gas-estimator-api 'https://gas-estimator.api.klymax402.com/mcp'
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "gas-estimator-api": {
            "type": "sse",
            "url": "https://gas-estimator.api.klymax402.com/mcp"
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. Gas Estimator API
  2. Quickstart -- MCP
  3. Quickstart -- HTTP (x402)
  4. Tools
  5. Example agent prompts
  6. Payment
  7. Part of klymax402
  8. License

Gas Estimator API

Multi-chain gas prices in one call -- ETH, Base, Polygon, Arbitrum, BSC. Compare chains to find cheapest. 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": {
    "gas-estimator": {
      "url": "https://gas-estimator.api.klymax402.com/mcp"
    }
  }
}

Quickstart -- HTTP (x402)

curl -X POST "https://gas-estimator.api.klymax402.com/api/estimate" \
  -H "Content-Type: application/json" \
  -d '{}'
# -> 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

ToolMethodPathPriceDescription
crypto_estimate_gasPOST/api/estimate$0.005Get gas price estimates across multiple EVM chains with USD cost
crypto_estimate_gas

Use this when you need to compare gas prices across multiple EVM chains at once. Returns multi-chain gas estimates in JSON.

Parameters

NameTypeRequiredDescription
chainstringnoChain name: ethereum, base, polygon, arbitrum, bsc. Omit for all chains.

Returns

  • chains -- array of chain gas data with chain name
  • low -- gas price in gwei for slow confirmation
  • medium -- gas price in gwei for standard confirmation
  • high -- gas price in gwei for fast confirmation
  • transferCostUsd -- estimated USD cost for a simple transfer on each chain
  • cheapestChain -- which chain currently has the lowest gas cost

Example response:

{"chains":[{"chain":"base","low":0.005,"medium":0.008,"high":0.012,"transferCostUsd":0.01},{"chain":"ethereum","low":12.5,"medium":18.0,"high":25.0,"transferCostUsd":0.85}],"cheapestChain":"base"}

When to use: choosing the cheapest chain before a cross-chain transaction. Essential for multi-chain agents that need to optimize gas costs.

Not for: swap quotes (use dex_get_swap_quote), bridging (use bridge_find_best_route).

Example agent prompts

  • "Compare gas prices across multiple EVM chains at once"

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.

License

MIT

Frequently asked questions

What is Gas Estimator API?

Multi-chain gas estimation — ETH, Base, Polygon, Arbitrum, BSC. x402 micropayment.

How do I install Gas Estimator API?

It runs as a remote server. In Claude Code: claude mcp add --transport sse gas-estimator-api 'https://gas-estimator.api.klymax402.com/mcp'. For other clients, paste the JSON configuration from this page into their MCP settings.

Does Gas Estimator API need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is Gas Estimator API open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains Gas Estimator API?

It is published by Br0ski777. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.