"Identifying Servers Without Any API Key Configuration" matching MCP servers:

MCP server for the Stashcat messenger API. Enables AI assistants to read and send messages, manage channels, conversations, files, polls, and more.

Experimental server that implements the Model Context Protocol (MCP) for Nylas API, providing resources, tools, and prompts to help developers integrate email, calendar, and contacts functionality with AI applications.

Enables to interact with Nylas API for email, calendar, and contacts via MCP, providing documentation, code samples, and code generation tools.

Japanese calendar API for AI agents. Provides Rokuyo, Rekichu, Eto, 24 Solar Terms, and fortune judgments. MCP + REST API.

Enables querying Japanese public holidays and calculating business days, including holiday checks, holiday lists, and business-day arithmetic.

Enables users to get and set meeting appointments in Google Calendar.

Exposes the Appointment Scheduler API to AI agents as an MCP server, enabling them to list users and services, check availability, book, list, and cancel appointments via natural language.

Enables AI assistants to manage Google Calendar events and Gmail emails through natural language. Supports creating/listing calendar events with smart color coding, sending/reading emails, and advanced search capabilities across both services.

Measures the shape of idle time in a booking calendar. Separates gaps that can actually be sold from structurally unsellable dead time, accounting for turnover time and the booking start grid. Fully offline, no API key required.

Provides real, official public holiday data for ~100 countries with tools to list holidays for a year and check if a specific date is a holiday. Free, no API key required, powered by Nager.Date.

Enables Claude (or any MCP client) to read and write events on your iCloud calendars via CalDAV.

Discovers events from Luma's public feed and subscribed calendars, with distance filtering, category search, and ICS export. No API key required for basic discovery.

Enables users to find available appointment slots from a public resource schedule over an inclusive date range, applying booking-window rules when requested. It returns wall-clock times and flags truncated result sets, operating read-only without account or API key.

Enables Claude to schedule, query, and cancel Calendly events via Calendly API v2, allowing direct event management without the public booking form.

MCP server for Claude to access on-premises Outlook/Exchange mailboxes via EWS with NTLM authentication, providing tools for email, calendar, and contact management without relying on Microsoft 365 or Graph API.

Enables AI assistants to read, search, and manage Outlook/Office 365 work mailboxes and calendars, and create reply drafts without sending by default.

Turn any calendar, contact book, or task list into an AI-orchestrated system. Platform-independent via CalDAV/CardDAV works with Nextcloud, Baikal, Fastmail, and any standards-compliant DAV server. 26 tools with field-agnostic updates.

Book a table, an appointment or a place in a class at a real local business. Live availability, instant confirmation, no account and no API key. Eight tools: search, fetch, get_business, check_availability, create_booking, check_booking, cancel_booking and request_listing. Guest emails in eight languages. Hosted at https://g-guest.app/api/mcp

Enables interaction with Outlook Web through its internal API, supporting email search, folder listing, email retrieval, read state changes, calendar events, and reply drafts without Microsoft Graph or COM.

Controls the Microsoft Outlook desktop app via COM automation, enabling email, calendar, and contact management without needing Graph API or Azure registration.