How do I use Mailosaur MCP?

1. Click on "Deploy Server". 2. Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state. 3. In the chat, type @ followed by the MCP server name and your instructions, e.g., "@Mailosaur MCP list messages from the last hour" That's it! The server will respond to your query, and you can continue using it as needed. Here is a step-by-step guide with screenshots.

Mailosaur MCP

by MrNewDelhi

Overview Schema Source Related Servers Discussions Admin

JavaScript

Remote

Mailosaur MCP

A full-featured Model Context Protocol server for Mailosaur email and SMS testing.

Features

List, search, wait for, retrieve, create, forward, reply to, and delete messages.
Manage Mailosaur servers and generate test email addresses.
Download EML files and attachments as base64 content.
Generate and download email preview screenshots.
Run spam and deliverability analysis.
Inspect account limits and transaction usage.
Create virtual security devices and retrieve TOTP codes.

The implementation is based on the official Mailosaur API and Node.js client surface. See Mailosaur API docs, Mailosaur Node.js docs, and Mailosaur email previews docs.

Related MCP server: mcp-imap

Setup

npm install
npm run build

Set your Mailosaur API key:

export MAILOSAUR_API_KEY="your_api_key"

MCP configuration

{
  "mcpServers": {
    "mailosaur": {
      "command": "node",
      "args": ["/absolute/path/to/mailosaur-mcp/dist/index.js"],
      "env": {
        "MAILOSAUR_API_KEY": "your_api_key"
      }
    }
  }
}

Local development

npm run typecheck
npm run build

Run directly during development:

MAILOSAUR_API_KEY="your_api_key" npm run dev

Tools

mailosaur_messages_get
mailosaur_messages_list
mailosaur_messages_search
mailosaur_messages_get_by_id
mailosaur_messages_create
mailosaur_messages_forward
mailosaur_messages_reply
mailosaur_messages_delete
mailosaur_messages_delete_all
mailosaur_messages_generate_previews
mailosaur_servers_list
mailosaur_servers_create
mailosaur_servers_get
mailosaur_servers_get_password
mailosaur_servers_update
mailosaur_servers_delete
mailosaur_servers_generate_email_address
mailosaur_files_get_email
mailosaur_files_get_attachment
mailosaur_files_get_preview
mailosaur_analysis_spam
mailosaur_analysis_deliverability
mailosaur_previews_list_email_clients
mailosaur_devices_list
mailosaur_devices_create
mailosaur_devices_otp
mailosaur_devices_delete
mailosaur_usage_limits
mailosaur_usage_transactions

Destructive tools require confirm: true.

Repository Skill

This repository includes a Codex skill at skills/mailosaur-mcp-builder. Use it when extending this MCP, auditing tool coverage against Mailosaur docs, or building another Mailosaur MCP implementation.

Available Tools

29 tools

mailosaur_analysis_deliverabilityC

Run deliverability analysis for a message.

Inputs: messageId (required).

mailosaur_analysis_spamC

Run spam analysis for a message.

Inputs: messageId (required).

mailosaur_devices_createB

Create a Mailosaur virtual security device from a base32 shared secret.

Inputs: sharedSecret (required), name.

mailosaur_devices_deleteC

Permanently delete a Mailosaur virtual security device.

Inputs: id (required), confirm.

mailosaur_devices_listA

List Mailosaur virtual security devices used for TOTP testing.

Inputs: no named parameters.

mailosaur_devices_otpB

Retrieve the current TOTP code for a saved device ID or base32 shared secret.

Inputs: query (required).

mailosaur_files_get_attachmentC

Download a message attachment. Returns base64 content.

Inputs: attachmentId (required).

mailosaur_files_get_emailC

Download a message as an EML file. Returns base64 content.

Inputs: messageId (required).

mailosaur_files_get_previewB

Download a generated email preview screenshot. Returns base64 content.

Inputs: previewId (required).

mailosaur_messages_createC

Create a message and optionally send it to a verified external address.

Inputs: server (required), to (required), cc, from, +5 more.

mailosaur_messages_deleteB

Permanently delete a message and its attachments.

Inputs: id (required), confirm.

mailosaur_messages_delete_allC

Permanently delete all messages and attachments on a server.

Inputs: server (required), confirm.

mailosaur_messages_forwardC

Forward an email message to a verified address.

Inputs: id (required), to (required), cc, text, +1 more.

mailosaur_messages_generate_previewsC

Generate screenshots of an email rendered in selected email clients.

Inputs: messageId (required), previews (required).

mailosaur_messages_getA

Wait for and return the first full message matching criteria. Best for test flows where an email/SMS may arrive shortly.

Inputs: server (required), criteria (required), options.

mailosaur_messages_get_by_idB

Retrieve the full detail for a single message by ID.

Inputs: id (required).

mailosaur_messages_listC

List message summaries for a server.

Inputs: server (required), options.

mailosaur_messages_replyC

Reply to an email message.

Inputs: id (required), body (required).

mailosaur_messages_searchC

Search message summaries by sender, recipient, subject, or body.

Inputs: server (required), criteria (required), options.

mailosaur_previews_list_email_clientsA

List email clients available for generated email previews.

Inputs: no named parameters.

mailosaur_servers_createC

Create a Mailosaur server.

Inputs: name (required).

mailosaur_servers_deleteB

Permanently delete a Mailosaur server and all contained messages.

Inputs: id (required), confirm.

mailosaur_servers_generate_email_addressB

Generate a random email address for a Mailosaur server.

Inputs: id (required).

mailosaur_servers_getB

Get a Mailosaur server by ID.

Inputs: id (required).

mailosaur_servers_get_passwordB

Get the SMTP/POP3 password for a Mailosaur server.

Inputs: id (required).

mailosaur_servers_listA

List all Mailosaur servers.

Inputs: no named parameters.

mailosaur_servers_updateC

Update a Mailosaur server.

Inputs: id (required), name (required).

mailosaur_usage_limitsB

Retrieve account usage limits. Requires an account-level API key.

Inputs: no named parameters.

mailosaur_usage_transactionsB

Retrieve recent transaction usage. Requires an account-level API key.

Inputs: no named parameters.

Tool Schema Changelog

Recent tool additions, removals, and schema changes observed during successful MCP inspections.

Loading tool schema changelog…

Deploy Server

One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

TDQS

B3.2/5.0

Scored 2026-05-18 06:15 across 29 tools

Disambiguation5/5

Each tool has a distinct resource-action pair clearly indicated by the naming convention, making it easy to differentiate between tools for different purposes.

Naming Consistency5/5

All tools follow a consistent 'mailosaur_<resource>_<action>' snake_case pattern, providing predictability and ease of understanding.

Tool Count2/5

With 29 tools, the count exceeds the typical well-scoped range (above 25), making the tool set feel heavy and potentially overwhelming for an agent.

Completeness5/5

The tools comprehensively cover server management, message lifecycle, device handling, file operations, analysis, and usage tracking, leaving no obvious gaps for email testing workflows.

Maintenance

ActivityInactive

ResponsivenessNo recent community issues

Resources

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Mailosaur MCP

Features

Setup

MCP configuration

Local development

Tools

Repository Skill

Available Tools

Tool Schema Changelog

TDQS

Maintenance

Resources

Related MCP Connectors

Related MCP Servers

mcp-outlook-mail

mcp-imap

CloudMailin MCPofficial

mailpit-mcp-server