"APIs Compatible with OpenAI for Conversational AI" matching MCP servers:

Pay-per-call USDC payment proxy for AI agents. Issue scoped Pay Tokens with hard spending caps and auto-journal every charge to freee / Money Forward / QuickBooks.

MCP server for creating and fiscalizing invoices via solo.com.hr API. Enables AI agents to generate invoices, retrieve invoice details, list invoices, and check next invoice number.

Discover audio and LLM services, compare seven voices, and check prices for free. Generate speech, transcribe audio and request LLM text with optional capped USDC payments on Base; voice-cloning requirements are also available.

Accounting AI - MCP server providing AI-powered tools and automation by MEOK AI Labs

Enables AI agents to browse, list, buy, review, and get paid for digital goods through MCP tools, including balance, ledger, checkout-link, upload, and payout operations. All money is simulated demo credits with no payment processor connected, and seller-authored text is returned in safe data envelopes.

Enables agents and humans to pay per question over x402 and receive plain-language answers about on-chain activity, priced by complexity before execution. Each paid request runs a live subgraph round trip to search, validate, generate and execute a GraphQL query, then synthesizes the raw results into a grounded response alongside the underlying data.

MCP server for matchmaking and dating, enabling users to register, answer a questionnaire, receive daily matches, and send paid greetings through natural language in AI chat interfaces like Claude and ChatGPT.

AI Agent Hub is a pay-per-call API platform for AI agents Every call is billed automatically in USDC using the x402 protocol - there is no API key, no account, and no signup. Agents get instant access to data queries, file storage, and ad impressions, paying only for what they actually use. The same tools are also exposed natively over MCP, so any MCP-capable agent can discover and call them

Free x402 endpoint checker plus paid report and metadata tools. Remote MCP server for agents. Written by AI named Nock, not a human.

Enables AI agents to browse product catalogs and make purchases through a policy engine that enforces spending limits, requires human approval for certain amounts, and logs all actions to an audit trail.

Invoice Generator AI - MCP server providing AI-powered tools and automation by MEOK AI Labs

Track SaaS subscriptions, renewal dates, spending, and find duplicate services.

Provides a three-layer payment firewall for AI agents, enabling identity verification, risk screening, and execution authorization with on-chain policy enforcement for secure and auditable transactions.

MCP server for Online Boutique AI Assistant that exposes 18 e-commerce microservice functions via the Model Context Protocol, enabling any MCP client to manage products, carts, checkout, payments, and shipping.

Remote MCP server providing free tools for value-bearing responses and trust receipts, plus optional consent-based commerce, enabling agents and humans to connect to a coordinated AI operator.

Lets AI agents and developers list a catalog of troubleshooting datasets, preview up to three records per product for free, and get Lightning payment instructions to unlock full structured datasets.

MCP server that provides tools for retrieving transaction context and recording AI decisions or creating human reviews for payment risk exceptions. Enables LLM agents to handle exception transactions in a hybrid payment-decisioning workflow.

Enables MCP-capable agents to read Fintaro invoices and transactions, and upload receipts, via a scoped API key with PII-safe projections.

Enables AI assistants to resolve CIMS parties, quote and send transfers, handle attestation, and track intent lifecycles on the Roots CIMS network, with built-in safety rails that refuse raw addresses and require confirmation before sending.

Enables users to retrieve BIN data for a given BIN number, with optional enhanced attributes for richer insights.