An MCP server for Fastmail - National Email Day

In brief

For National Email Day, we’re shipping something new. Fastmail now has an MCP server at https://api.fastmail.com/mcp.

MCP is an open standard, not tied to any one AI provider, for how AI clients talk to external data and tools. Think of it as another API sitting alongside IMAP, CalDAV, and CardDAV, except instead of being designed for mail apps or calendar clients, it’s designed for AI models to use directly.

So if you point your AI client (like Claude or ChatGPT) at our MCP server, you can ask it things like “what’s on my calendar tomorrow?”, “draft a reply to Sarah’s email about the Q3 budget”, or “find my dentist’s address in my contacts” and it will do them against your real Fastmail account.

The longer story - your data, your choice

To be clear about what this isn’t: we have not integrated AI into Fastmail. There’s no chatbot bolted onto the inbox, and your mail isn’t being piped through a model in the background. The MCP server is simply another API endpoint for you to use, if you want to, with the AI client of your choice.

That distinction matters to us. Our long-term values include “Your data belongs to you” and “We are good stewards of your data”. The pattern we try to follow is: rather than continuously reworking our UI to follow every new trend, we give you the interfaces to use your data however it suits you. MCP continues that pattern. It’s there if you want it, and nothing changes if you don’t.

Using it is straightforward. Most AI clients (Claude, ChatGPT, and others) let you configure a list of MCP servers they’re allowed to access. You add https://api.fastmail.com/mcp, complete an OAuth consent screen to authorise the connection, and from then on your AI can read and act on your mail, calendar, and contacts when you ask it to.

The OAuth consent screen will give you a choice of three levels of access: read-only (see emails, contacts, calendars), write (update emails, save drafts, edit contacts and events), and send (send emails).

AI in your app, or your app in AI?

When thinking about how webapps and AI integrate, there are two main ways of looking at it.

The first (and the default today) is to integrate AI into the webapp. The webapp provider picks an AI system, builds it in, and ships it as a feature. A chat panel in the corner, a “summarize this” button, and so on. Each webapp ends up with its own AI, chosen by the developer, and none of them know anything about each other: your email has one AI, your project management system another, your document editor a third. From the user’s perspective, AI becomes a scattered collection of disconnected helpers, each confined to the webapp it shipped with and each missing the context that lives in the others.

The second approach is to integrate the webapp into the AI itself. Here the user (not the app vendor) chooses the AI (maybe even local models run on just the user’s own devices), and that AI becomes a persistent interface that gets to know them over time. It can reach into whichever webapps the user has connected, pulling together context across email, projects, documents, and everything else and acting on their behalf. The webapp stops being a silo with its own bolted-on AI feature and starts being a system that the user’s AI can draw on.

This second model is what MCP (Model Context Protocol) is designed to enable. It gives AI assistants a standard way to discover webapps, read data from them, and call functions on them, so that a single AI can orchestrate work across all the services a user has connected.

The MCP Apps spec extends this further. It lets a webapp render its own UI inside the AI’s interface, so that interacting with a third-party service can feel native within the AI conversation rather than bouncing the user out to a separate tab.

In that context, it’s not surprising then that MCP and MCP Apps are being driven by Anthropic, and other AI-only providers (like OpenAI) have also jumped on board as well. Meanwhile Google (at the time of writing) has no support in their Gemini chat UI for it, though there is support in some of the more developer-focused CLI tools. Google is simultaneously the ‘everything’ webapp, the AI provider, and the largest advertiser targeting you. They have an obvious incentive to favour the first model to keep you and your data within their own systems.

Email - still the world’s largest communication platform

Email is the world’s largest communication platform. It’s also open and federated across millions of providers rather than siloed inside a single organisation. That gives it a unique place in the world as your electronic memory that isn’t controlled by any one organisation. That also means everyone uses it in their own unique way, and Fastmail will continue to evolve to allow users to use their email, contacts, calendars and files how they want and where they want.

Happy National Email Day!