"Connecting to an External API for Agent-Based Replies" matching MCP servers:

Free DEX aggregator API that returns executable swap calldata across 46 EVM chains. No API key required. Single GET request returns ready-to-sign transactions for any token pair.

Bitcoin data for AI agents. Pay-per-query via x402 micropayments. No API keys. No subscriptions. No tokens.

MCP server providing real-time crypto prices (Chainlink + Binance), Polymarket prediction market data, deep web research, and JS-rendered web scraping. All services available via x402 Solana micropayments.

Pay-per-task AI agent for writing, research, code, DeFi & blockchain. Pay in USDC on Base or Solana. Supports A2A, MCP, x402 and Agentmail protocols.

55+ pay-per-call tools for AI agents over MCP: live telemetry, blockchain/on-chain checks, environmental, transit, finance, and network utilities. No API key or signup — agents pay per request with x402 USDC micropayments (Base and Solana).

MCP server for pay-per-call DeFi and crypto data via x402 micropayments on Base. 8 endpoints: token prices, TVL, funding rates, token security, gas tracker, whale monitoring, wallet profiling, and yield scanning.

Non-custodial crypto swaps for AI agents: Solana (Jupiter) + 7 EVM chains (KyberSwap), 1288+ assets, cross-chain routing, priority-fee oracle, Hyperliquid perps. Returns unsigned transactions — your wallet signs, no API key, no KYC. Hosted at https://swaptitan.net/mcp

Real-time crypto, stock, and prediction-market data for agents — prices, indicators, funding rates, DeFi TVL, macro calendar, and an AI momentum score. Configure one Base wallet key and it just works. No signup, no dashboard, no subscription.

Enables agents to access live DeFi, social intelligence, risk, and API documentation tools with a caller-supplied API key.

Enables agents to purchase and use compute resources on Robinhood Chain via x402 payments. Provides tools for thinking, renting GPUs, checking balances, and viewing the compute menu.

Enables users to discover, redact, and upload coding-agent traces, then earn USDC/USDT by selling access to those traces to researchers and model trainers.

MCP server for cross-chain bridging, enabling AI agents to find routes, estimate costs, check risks, execute transfers, and track status across blockchains.

43 x402-enabled API tools — DeFi, wallet security, AI/ML, developer tools, SEO. Pay-per-call USDC on Base via x402 protocol.

Non-custodial BVCC Agent Wallet MCP server: let an AI agent check balances, send native/ERC-20, approve, and swap on Uniswap v3/v4 across Ethereum, BNB Chain, Arbitrum and Base, within on-chain enforced limits.

An MCP server that enables LLMs to query DAOs, proposals, and voting data from Tally's blockchain governance API across multiple networks.

Enables AI assistants to query blockchain chain data, including chain details, RPC endpoints, and chain relationships, through a Model Context Protocol server.

A Model Context Protocol server implementation that provides endpoints for wallet-based authentication, cluster management, and name registration services.

MCP server that lets AI agents scrape web pages as clean markdown for a micro-payment in USDC, using the x402 protocol on Base network. No API keys or signup required.

Enables AI agents to securely execute peer-to-peer tasks on the XRP Ledger by locking payment in escrow, submitting proof of completion, and receiving an objective PASS/FAIL judgement from an independent AI referee.

Agent-Q is an MCP server that separates execution surfaces from signing authority, enabling secure Sui signing flows where the signing device holds keys and policy while requesters submit bounded signing requests through a local host process.