"Servers that support Server-Sent Events (SSE)" matching MCP servers:

Read-only MCP server that performs deterministic local preflights of agent-payment boundary documents and x402 v2 PaymentRequired JSON, and prepares unsubmitted public quote-request drafts without network calls or fund movement.

Checks live x402 routes across Base, Solana, and Algorand before agents spend. $0.003 USDC settles only for a valid live eligible route; normal typed misses are not settled. Free preview and validate tools. Seller payment is separate; the agent keeps its wallet. Optional signed route-binding receipts support buyer-side checks.

A paid MCP server that lets AI agents send SMS messages to US phone numbers via x402 micropayments, with automatic compliance and opt-out handling.

PayCheck is an MCP server that checks a planned payment before an agent pays.

MCP server for the Gravv payments API that lets AI assistants onboard customers, run KYC, open accounts, move money, issue cards, and exchange currency, with built-in documentation search and safety confirmations for money-moving operations.

MCP server for NovaPay that enables AI agents to create payment links, poll payment status, manage session lifecycle, and generate merchant keys.

Enables AI assistants to interact with the Paxaver school lunch platform, allowing users to check menus, order lunch, manage wallet funds, register for events, donate, and perform administrative tasks like managing restaurants and menu items.

A template for building MCP servers with a built-in paywall gate that offers free local execution and premium server-side execution via Stripe and x402 payment lanes.

Create free, no-signup invoices from your AI assistant — the create_invoice tool returns a link that opens blankinvoicemaker.com pre-filled, ready to download as a watermark-free PDF.

A Model Context Protocol server that enables interaction with Monobank API, providing tools for currency exchange rates, client info, and account statements.

Mercury Banking MCP server with full Invoicing API support. Read accounts/transactions and create/manage recurring invoices via Model Context Protocol.

Enables issuing credit notes and credit memos against an invoice or standalone as revisable drafts that can be finalized into frozen numbered documents, then rendered as Markdown or printable HTML with totals broken down by currency, reason and month. All amounts are handled as integer minor units and all data stays local, so nothing is sent anywhere.

MCP server for the PayPay Open Payment API, enabling QR code creation, payment tracking, refunds, and cancellations with sandbox and production support.

Budget, approval, and receipt layer that agents call when they buy on a human's behalf. MCP server with dry-run by default.

Enables AI assistants and agents to vet a stablecoin or x402 payment before it is sent, returning an approve, hold, or reject decision from instant rule checks and an optional locally-run risk model. Fails closed, so malformed input or an unreachable model yields a hold rather than an approval.

Enables AI agents to stamp, cancel, and query Mexican CFDI 4.0 invoices through MCP tools, with support for local stdio and hosted HTTP transport.

A recoverable Firecrawl MCP server that adds payment lifecycle, idempotency, and automatic refunds/fallbacks to web scraping, enabling reliable paid scraping via natural language.

Enables AI clients to check an application balance and preview or send bulk SMS and airtime, either through a hosted OAuth connection that needs no local install or via a self-hosted stdio/Cloudflare Workers deployment using your own credentials. Sending is preview-only by default and gated behind environment, recipient allowlist, and mutation opt-in settings.

Decodes HTTP 402 challenges into exact payment and retry steps, recommends a payment rail from stated requirements, and searches an open registry of scored payment solutions with scheme references and support probing. Every tool is read-only, so nothing can spend money.

Connects Claude to the customer side of Housecall Pro, letting you view estimates and invoices, check company details, and decline estimate options using the link your contractor sent.

MCP server that checks an x402 paid endpoint before an agent pays it, and checks afterwards that the receipt opens to exactly one real on-chain settlement. Two tools, no account, no API key.

Enables users to track unpaid invoices and generate an escalating ladder of payment-reminder letters — first reminder, second reminder, and final notice — anchored to the due date, plus overdue listings, aging buckets, and a daily chase list of what to send today. It records payments and letters sent, rendering each letter as Markdown or printable HTML without ever emailing anything itself.

MCP server for the Monei API that gives AI agents access to wallets, transfers, crypto sends, swaps, offramp, and bill payments through natural language.

MCP server that gives Claude/GPT agents commerce tools — each tool call pays an upstream x402 endpoint and returns its artifact.

MCP server that reads and annotates Kontist business banking data, including balances, transactions, and tax reserves.

MCP server that gives AI assistants real-time access to Stripe business metrics like MRR, churn, and revenue forecasts via natural language queries.

MCP server that enables AI agents to request human approval before spending money, check approval status, verify signed tokens, and manage API keys.

a paying-fetch client with spending controls you set, and a wallet that stays yours.

Enables any existing API to become a pay-per-call service for agents by issuing HTTP 402 payment requests and settling USDC payments via CDP, while exposing MCP tools that charge per call and support Bazaar discovery.

Enables AI agents to query Paraguayan SIFEN electronic documents, download KuDE PDFs, look up taxpayers by RUC or cédula, check plan usage, and calculate totals with official SET rounding, plus optionally issue invoices, credit and debit notes, and register cancellation, annulment, or nomination events when write mode is explicitly enabled. Runs locally over stdio with the user's own API key and is read-only by default.