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Setup Guide
Setup guide

Set up MAILsimple with Claude

This guide walks you through everything from creating your account to connecting mailboxes and adding MAILsimple to Claude Code. Most people are up and running in a few minutes.

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1. Create your account and choose a plan

Head to account.ccmssolutions.com and create your account. Choose the plan that fits:

  • Free: one connected mailbox (Outlook or IMAP) at no cost.
  • Pro: $9/month or $90/year (two months free) for unlimited mailboxes.

Your account portal is where you manage your plan and billing, and where you create the API key you will use in step 4.

Create your account Sign in

See our Terms of Service and Privacy Policy.

2. Connect an Outlook / Office 365 mailbox

Sign in to the connector at mailsimple-mcp.ccmssolutions.com and add your mailboxes there.

  1. Choose Add Outlook.
  2. You are redirected to Microsoft's official sign-in to authorize access. MAILsimple never sees your Microsoft password.
  3. Review the permissions Microsoft shows you and approve. You are returned to MAILsimple with the mailbox connected.

Repeat for as many Outlook / Office 365 accounts as your plan allows. On Free you can connect one mailbox; on Pro you can connect as many as you need.

3. Connect an IMAP/SMTP mailbox

MAILsimple works with any standard IMAP/SMTP mailbox: custom domains, hosting providers, and most email services.

  1. At mailsimple-mcp.ccmssolutions.com, use the IMAP form to add a mailbox.
  2. Enter your incoming (IMAP) server host and port, and your outgoing (SMTP) server host and port. Your email provider publishes these settings.
  3. Enter your username (usually your full email address) and password. If your provider uses two-factor authentication, create an app password and use that here.
  4. Choose Add mailbox. MAILsimple validates the connection and encrypts your credentials at rest.

If a connection fails, double-check the host, port, and whether your provider requires an app password rather than your normal login.

4. Get your API key

Claude authenticates to MAILsimple with an API key from your account.

  1. Sign in at account.ccmssolutions.com and open API Keys.
  2. Choose MAILsimple and click Generate key.
  3. Copy the key. It starts with csk_ and is shown only once; we store just a secure hash, so it cannot be displayed again.

Treat the key like a password. If it is ever exposed, revoke it on the same page and generate a new one; the old key stops working immediately.

5. Install the plugin in Claude Code

MAILsimple is delivered to Claude Code as a plugin from the MAILsimple marketplace. In Claude Code, run:

/plugin marketplace add ccms-inc/mailsimple-marketplace
/plugin install mailsimple-connector@ccms-hosting

The plugin contains no secrets. It simply points Claude Code at the MAILsimple endpoint and reads your key from your environment.

6. Connect: set your endpoint and key

The plugin reads two environment variables. Set them in the environment Claude Code runs in:

  • MAILSIMPLE_MCP_URL: https://mailsimple-mcp.ccmssolutions.com/mcp (note the /mcp path)
  • MAILSIMPLE_CONNECTOR_KEY: your csk_... key from step 4
# macOS / Linux (add to your shell profile)
export MAILSIMPLE_MCP_URL="https://mailsimple-mcp.ccmssolutions.com/mcp"
export MAILSIMPLE_CONNECTOR_KEY="csk_your-key-here"

# Windows PowerShell (persists for your user)
setx MAILSIMPLE_MCP_URL "https://mailsimple-mcp.ccmssolutions.com/mcp"
setx MAILSIMPLE_CONNECTOR_KEY "csk_your-key-here"

Restart Claude Code so the plugin picks up the values, then ask Claude: “List my mail accounts.” It should return the mailboxes you connected in steps 2 and 3.

If Claude reports an authentication error, confirm the key is active under API Keys and that your subscription is current. A 404 usually means the URL is missing the /mcp path.

Using another MCP client

MAILsimple is a standard remote MCP server (Streamable HTTP), so it also works with any MCP client that can send an Authorization: Bearer header. Point the client at https://mailsimple-mcp.ccmssolutions.com/mcp and send your key as Authorization: Bearer csk_....

Note: the custom-connector flows in the Claude Desktop and claude.ai apps expect an OAuth sign-in, which MAILsimple does not offer yet, so pasting a key there will not connect. Use Claude Code with the plugin above.

7. Manage mailboxes and permissions

From the connector at mailsimple-mcp.ccmssolutions.com you control exactly what Claude can do with each account:

  • Set per-account permissions for read, send, and delete.
  • Add or remove mailboxes at any time.
  • Disconnect a mailbox to revoke access immediately.
  • Review the action audit trail to see what was done and when.

Permissions are enforced on every request, so a mailbox set to read-only can never be used to send or delete, even if asked.

8. Security and privacy

  • Outlook / Office 365 is connected through Microsoft's official OAuth sign-in; MAILsimple never stores your Microsoft password.
  • IMAP/SMTP credentials and OAuth tokens are encrypted at rest.
  • Each account's read, send, and delete permissions are enforced on every request.
  • Every action Claude takes is recorded in an audit log.
  • We do not sell your data, and we do not use your mailbox contents to train models.

For more detail, see our Privacy Policy and Terms of Service.

Ready to connect your inboxes?

Create your account, connect your first mailbox for free, and add MAILsimple to Claude Code.

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