# LogicNodes > Free, Blocknative-compatible multi-chain gas price API with MCP and A2A access for AI agents. ## Endpoints - [Gas prices](https://logicnodes.io/gasprices/blockprices): GET ?chainid=&confidenceLevels=99,95,90,80,70. Default chainid=1. - [Health](https://logicnodes.io/a2a/health): status and per-chain freshness. - [MCP (Streamable HTTP)](https://logicnodes.io/mcp): tools get_gas_prices, list_supported_chains. - [MCP (legacy SSE)](https://logicnodes.io/sse) - [A2A agent card](https://logicnodes.io/.well-known/agent-card.json) - [ERC-8004 registration](https://logicnodes.io/.well-known/erc8004-registration.json) - [OpenAPI](https://logicnodes.io/openapi.json) ## Supported chains (chainid) - Ethereum (1) - Base (8453) - Arbitrum One (42161) - OP Mainnet (10) - Polygon PoS (137) - BNB Chain (56) - Avalanche C-Chain (43114) - Linea (59144) - Scroll (534352) - zkSync Era (324) - Gnosis (100) - Blast (81457) - Mantle (5000) - Celo (42220) ## Notes - No API key required. Units are gwei. Response format matches Blocknative blockprices. - Free tier: 120 requests/minute per IP. Over the limit you get HTTP 429 with a Retry-After header. A once-a-minute poller is never affected. - Errors are JSON: {"error": "...", "message": "..."} with 400 (bad input) or 503 (stale data). ## Multi-chain and Aptos tools (read-only, free) Every tool takes JSON and returns {tool, ok, value|error, provenance, receipt}. Chains are CAIP-2 ids only (eip155:8453, aptos:1, aptos:2); names like "base" are refused. Ambiguous input (e.g. the symbol USDC on Aptos) returns AMBIGUOUS_INPUT with every option, never a guess. Amounts are decimal strings. - [Tool list with JSON Schemas](https://logicnodes.io/v1/tools): GET - Call: POST https://logicnodes.io/v1/tools/ with the input as the JSON body (also available over MCP at https://logicnodes.io/mcp/v2; https://logicnodes.io/mcp keeps its original two tools) - [Aptos guide](https://logicnodes.io/aptos) - chain_info: Chain info - gas_estimate: Gas / fee estimate - address_validate: Validate an address - token_amount_convert: Convert token amounts - tx_status: Transaction status - aptos_address_validate: Validate an Aptos address - aptos_name_resolve: Resolve an Aptos name (.apt) - aptos_asset_resolve: Resolve an Aptos asset - aptos_amount_convert: Convert an Aptos amount - aptos_balance_get: Aptos balances at a ledger version - aptos_fee_estimate: Aptos fee estimate - aptos_tx_simulate: Simulate an Aptos transaction - aptos_tx_decode: Decode an Aptos entry-function call - aptos_tx_status: Aptos transaction status - aptos_view: Call an Aptos view function - decimal_calc: Exact decimal arithmetic - table_calc: Exact math over a table (sums, averages, per-group totals) — no hallucinated numbers - verify_answer: Check numbers before you send them (correct / wrong + the right value) - quote_check: Does the source really say this? (quote and citation check) - text_facts: Exact counts, limits and differences for text - reconcile: Reconcile two lists (bank vs ledger, invoices vs payments): matched, mismatched, missing - json_check: Is this JSON valid and does it match the schema? (exact errors with paths) - invoice_check: Compute or check an invoice exactly (lines, discounts, tax, shipping, total) - timesheet_calc: Hours, overtime and pay from clock-in/out entries (exact) - list_ops: Exact list operations: dedupe, sort, union, intersection, difference, compare - contact_normalize: Clean and dedupe emails and phone numbers (E.164) - find_free_slots: Meeting times that work for everyone (time zones and DST handled) - date_series: Recurring dates: every 2nd Tuesday, last business day of the month, every 2 weeks - table_join: Join two tables on a key (VLOOKUP done exactly) - pii_redact: Find and redact personal data and secrets in text before it is logged or shared - id_check: Validate identifiers by their check digits (IBAN, routing number, barcode, ISBN, VIN, NPI, EIN) - table_profile: Profile a spreadsheet: what every column holds and what is wrong with it - holiday_calendar: Public holidays by rule: US federal, England and Wales bank holidays (with observed dates) - fx_rate: Currency conversion at official ECB reference rates (dated, never guessed) - slippage_bounds: Slippage bounds in base units - swap_price_impact: Constant-product swap output and price impact - money_calc: Currency-aware money math - interest_calc: Simple and compound interest - loan_calc: Level-payment loan - unit_convert: Exact unit conversion - address_format_check: Cross-chain address format check - time_convert: Time zone conversion - business_days: Business-day arithmetic - evm_balance: EVM balances at one block - evm_nonce: EVM account nonce - evm_block: EVM block summary - evm_tx_receipt: EVM transaction receipt - evm_token_metadata: ERC-20 token metadata - evm_allowance: ERC-20 allowance - evm_contract_type: Classify an EVM address - evm_logs: EVM event logs (bounded) - evm_calldata_decode: Decode calldata with your ABI - evm_log_decode: Decode an event log with your ABI - payment_verify: Verify a token payment from a receipt - random_from_block: Verifiable randomness from a finalized block - erc8004_agent: ERC-8004 agent identity - erc8004_reputation: ERC-8004 reputation evidence - evm_spend_report: Wallet token spend report (CSV) - x402_settlement_verify: Did this agent really pay me? (x402 settlement check) - token_price: Token price in USD (two exchanges must agree) - ens_resolve: ENS name to address, or address to ENS name - tx_safety_check: Is this transaction safe to sign? (simulate + risk check) - sanctions_check: Sanctions screening for a crypto address - counterparty_check: Can I trust this counterparty? (sanctions, history, identity, verified deals) - wallet_watch_create: Watch a wallet for 30 days (signed webhooks) - wallet_watch_status: Status and recent events of a wallet watch - wallet_watch_cancel: Cancel a wallet watch - audit_log_create: Create a tamper-evident audit log - audit_log_append: Append an entry to an audit log - audit_log_export: Export an audit log with its integrity check - deal_dispute_review: Advisory ruling on a notarized deal (dispute review) - operator_verify_start: Start verifying the domain behind an agent - operator_verify_check: Check and issue the verified-operator badge - agent_register_prepare: Prepare an agent's ERC-8004 registration (free) - agent_register_publish: Host the agent's files and build its ERC-8004 registration transaction - x402_service_search: Find a paid API for a task (ranked x402 services) - x402_provider_report: Everything measured about one x402 provider - x402_monitor_create: Monitor an x402 provider for 30 days (signed webhooks) - x402_monitor_status: Status and recent alerts of a provider monitor - x402_monitor_cancel: Cancel a provider monitor - x402_provider_claim: Claim your provider listing (free) ## More - [Full reference](https://logicnodes.io/llms-full.txt) - [Docs](https://logicnodes.io/docs) - [Status](https://logicnodes.io/status)