Gas Oracle API

Live gas prices with gwei tiers, USD cost estimates, and congestion level. Time your transactions perfectly. 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-oracle": {
      "url": "https://gas-oracle.api.klymax402.com/mcp"
    }
  }
}

Quickstart -- HTTP (x402)

curl "https://gas-oracle.api.klymax402.com/api/price"
# -> 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
gas_get_current_price	GET	/api/price	$0.003	Get current gas prices with slow/standard/fast/instant tiers
gas_get_current_price	POST	/api/price	$0.003	Get current gas prices with slow/standard/fast/instant tiers (POST variant)

gas_get_current_price

Use this when you need current gas prices before submitting a transaction. Returns gas tiers and USD cost estimates in JSON.

Parameters

Name	Type	Required	Description
chain	string	no	Blockchain network (default: base)

Returns

• slow -- gas price in gwei for slow confirmation (~5 min)
• standard -- gas price in gwei for standard confirmation (~2 min)
• fast -- gas price in gwei for fast confirmation (~30s)
• instant -- gas price in gwei for instant confirmation
• transferCostUsd -- estimated USD cost for a simple ETH transfer
• swapCostUsd -- estimated USD cost for a token swap
• congestion -- network congestion level (low/medium/high)

Example response:

{"slow":0.008,"standard":0.012,"fast":0.018,"instant":0.025,"transferCostUsd":0.02,"swapCostUsd":0.05,"congestion":"low","chain":"base"}

When to use: submitting any on-chain transaction to pick the right gas tier. Essential for timing transactions and avoiding high-gas periods.

Not for: swap quotes (use dex_get_swap_quote), wallet balance (use wallet_get_portfolio).

gas_get_current_price

Use this when you need current gas prices before submitting a transaction. Returns gas tiers and USD cost estimates in JSON. POST variant of gas_get_current_price -- same params passed as JSON body instead of query string.

Parameters

Name	Type	Required	Description
chain	string	no	Blockchain network (default: base)

Returns

• slow -- gas price in gwei for slow confirmation (~5 min)
• standard -- gas price in gwei for standard confirmation (~2 min)
• fast -- gas price in gwei for fast confirmation (~30s)
• instant -- gas price in gwei for instant confirmation
• transferCostUsd -- estimated USD cost for a simple ETH transfer
• swapCostUsd -- estimated USD cost for a token swap
• congestion -- network congestion level (low/medium/high)

Example response:

{"slow":0.008,"standard":0.012,"fast":0.018,"instant":0.025,"transferCostUsd":0.02,"swapCostUsd":0.05,"congestion":"low","chain":"base"}

When to use: submitting any on-chain transaction to pick the right gas tier. Essential for timing transactions and avoiding high-gas periods.

Not for: swap quotes (use dex_get_swap_quote), wallet balance (use wallet_get_portfolio).

Example agent prompts

• "Current gas prices before submitting a transaction"
• "Current gas prices before submitting a transaction"

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