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Fastmail

What it is

An independent, privacy-focused email and calendar provider that serves as a high-performance alternative to Gmail and Outlook, built on modern, open standards.

What problem it solves

Provides a fast, ad-free, and private interface for email, calendar, and contacts without the data mining common in free services. It is a primary driver of the JMAP protocol, ensuring high interoperability for agents and modern apps.

Where it fits in the stack

Category: Calendar & Tasks / Ecosystem Provider. It acts as the "Source of Truth" for email and scheduling data in a de-Googled stack.

Typical use cases

  • Primary Communication Hub: High-speed personal or business email and calendar hosting.
  • Privacy Management: Using Masked Emails to prevent tracking across different services.
  • Agentic Mail Processing: Leveraging JMAP for reliable, stateless interaction with email and calendar data by LLM agents.
  • Custom Domain Hosting: Managing professional identities with advanced alias and catch-all support.

Strengths

  • Speed: The web and mobile interfaces are exceptionally fast and bloat-free.
  • Privacy: No tracking or ads; data is never sold. Employs on-server encryption for mail at rest.
  • Standards-First: Strong support for JMAP, CalDAV, and CardDAV.
  • Masked Email (2026): Deeply integrated with 1Password and bitwarden for generating site-specific aliases.

Limitations

  • Subscription-Based: No free tier; subscription is required for all features.
  • Collaborative Suite: Lacks the deep "doc" and "spreadsheet" ecosystem of Google Workspace.
  • Storage Limits: While generous, storage is capped based on the subscription tier (Standard vs Professional).

When to use it

  • If you want to "de-Google" your personal productivity stack while maintaining high performance.
  • When you value privacy and open standards (JMAP).
  • If you use custom domains and need powerful alias management.

When not to use it

  • If you require a free-forever service.
  • If your workflow is deeply dependent on Google Sheets/Docs for real-time collaboration.

Licensing and cost

  • Open Source: No (Server side), but contributes heavily to open-source protocols.
  • Cost: Paid (Subscription)
  • Self-hostable: No

Getting started

Installation (CLI)

The community-maintained fastmail-cli (Rust-based) provides a robust interface for interacting with Fastmail services.

# Install via Cargo
cargo install --git https://github.com/Lutra-Fs/fastmail-CLI

# Run interactive setup (requires an API token from Settings > Security > API Tokens)
fastmail setup

Hello World (Masked Email)

Creating a masked email directly from the command line: 

# Create a new masked email for a specific site
fastmail masked create https://example.com --description "Batch 109 Audit"

CLI examples

The fastmail-cli tool supports mail, contacts, calendars, and masked emails.

# List all calendars associated with the account
fastmail calendar list

# List recent emails from the 'Inbox'
fastmail mail list --mailbox Inbox --limit 10

# List all active masked emails
fastmail masked list

# Create a new contact
fastmail contacts create "Jane Doe" --email "jane@example.com"

API examples

Fastmail is a primary driver of the JMAP (JSON Meta Application Protocol) standard.

Fetch Calendar Events (Python)

This pattern is used by agents to synchronize schedules without the overhead of CalDAV. 

import requests

api_token = "your_api_token"
url = "https://api.fastmail.com/jmap/api/"

headers = {
    "Authorization": f"Bearer {api_token}",
    "Content-Type": "application/json"
}

payload = {
    "using": [
        "urn:ietf:params:jmap:core",
        "urn:ietf:params:jmap:calendars"
    ],
    "methodCalls": [
        ["CalendarEvent/get", {
            "accountId": "primary",
            "ids": None,
            "position": 0,
            "limit": 10
        }, "0"]
    ]
}

response = requests.post(url, headers=headers, json=payload)
events = response.json()['methodResponses'][0][1]['list']
for event in events:
    print(f"Event: {event['title']} ({event['start']})")

Generate Masked Email (cURL)

curl -X POST https://api.fastmail.com/jmap/api/ \
  -H "Authorization: Bearer $FASTMAIL_TOKEN" \
  -d '{
    "using": ["https://www.fastmail.com/dev/maskedemail"],
    "methodCalls": [
      ["MaskedEmail/set", {
        "create": {
          "m1": { "forDomain": "example.com", "state": "enabled" }
        }
      }, "0"]
    ]
  }'

Sources / References

Contribution Metadata

  • Last reviewed: 2026-05-30
  • Confidence: high