"Services or tools that don't require a separate API key" matching MCP servers:

MCP server that gives AI agents direct access to Google services including Gmail, Calendar, Drive, and more, with multi-account OAuth support. Enables reading and sending email, managing calendar events, and interacting with Google files through natural language.

Enables AI agents to analyze whether they should send an email, evaluating passive aggression and regret probability with a recommendation heavily weighted toward no.

Enables AI agents to access 13 paid micro-tools over x402, paying per request in USDC on Base without API keys or signup. It covers email deliverability, grading, and templates, plus utilities like crypto prices, domain age, hashing, JSON conversion, JWT decoding, regex, slugs, UUIDs, and weather.

An MCP server that provides AI agents with direct access to authoritative Cakemail API specifications, enabling accurate code generation and eliminating hallucination.

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

A collection of MCP servers for Apple macOS apps (Mail, Contacts, Notes, Memory, Messages, Calendar, Reminders) enabling AI assistants to read, search, create, and update data via JXA, SQLite, and EventKit.

A collection of three zero-dependency MCP servers for web scraping via Chrome DevTools Protocol, crypto wallet and price monitoring, and email validation with SMTP sending.

Query your domains, sender compliance status, and Gmail traffic metrics from Claude, Cursor, or any MCP client using the Gmail Postmaster Tools API.

Comprehensive email validation MCP server that checks syntax, MX records, disposable domains, role-based accounts, SPF/DKIM, typo suggestions, and risk scoring.

MCP server for inspecting email domains and addresses, providing objective domain-level email infrastructure answers such as MX, SPF, DMARC, MTA-STS, and disposable-domain evidence.

MCP server for email deliverability: validate SPF/DKIM/DMARC/BIMI, check blacklists, test SMTP/IMAP, look up DNS, and generate ready-to-deploy records for any major email provider. Ships with two one-click prompts (audit-deliverability, setup-dns). Public, no auth.

A full-featured Model Context Protocol server that gives AI assistants real-time access to Google Workspace services including Drive, Gmail, Calendar, Sheets, Docs, and Apps Script.

Enables AI agents to send and draft Gmail emails and append content to Google Docs through standardized MCP tools.

A utility MCP server providing 10 specialized tools for newsletter content preparation and optimization, including subject line generation, HTML-to-text extraction, read time estimation, and email validation. Enables newsletter operators, developers, and content teams to automate pre-send workflows and audit newsletter issues through natural language interactions.

MCP server for Claude Desktop providing access to Google Sheets, Gmail, and Google Calendar.

A Model Context Protocol server that provides tools for weather forecasting and Gmail interaction.

Sendmux is an email inbox API and email API for AI agents. Use this MCP server to let authorised agents work with Sendmux mailboxes, inbound email, clean JSON parsing, webhooks, outbound sending, provider routing, logs, billing, and team controls.

Enables AI assistants to interact with Gmail and Google Docs, allowing them to send emails, create drafts, append content to documents, and retrieve document information.

An MCP server for managing Proton Mail, Pass, Drive, and Calendar through local IMAP/SMTP, pass-cli, and Proton Drive CLI, enabling AI agents to operate the mailbox, manage passwords, sync files, and classify emails.

Enables AI assistants to interact with Microsoft 365 and Office services through the Microsoft Graph API, providing tools for email, calendar, files, Teams, SharePoint, and more with configurable permissions and output formats.