Mailcheck

Overview

Mailcheck is an email verification service that helps businesses validate email addresses to ensure deliverability and reduce bounce rates. With the Mailcheck integration in SquadOS, your agents can verify emails in real time and validate domains for MX records, disposable email services, and spam indicators — directly within any automated workflow.

• Composio documentation: docs.composio.dev/toolkits/mailcheck

Authentication

This tool uses API key (API_KEY) to connect.

You will need the following fields:

Field	Required	Description
api_key	Yes	API key generated from your Mailcheck account dashboard, used to authenticate all requests.

How to get credentials

1. Go to app.mailcheck.co and create or log in to your account.
2. In the dashboard, navigate to the API or Settings → API Keys section.
3. Generate a new API key and copy the displayed value.

Tip

Keep your API key in a safe place. It authenticates all requests and is tied to your account’s credit balance.

How to connect in SquadOS

1. Go to Tools in the side menu (/admin/tools).
2. Open the Available tab and search for Mailcheck.
3. Click the card to open the details and hit Connect.
4. You’re taken to the secure connection page hosted by Composio, where you enter the credentials obtained above.
5. Once done, you’re sent back to SquadOS with the account connected and the tool available to your agents. (Connection-flow details in Organization Tools.)

Available actions

Validate Domain

MAILCHECK_VALIDATE_DOMAIN

Tool to validate a domain for disposability, MX records, domain age, and spam indicators. Use when checking if a domain is associated with temporary email services, public email providers, or forwarding services.

Input parameters

Name	Type	Required	Description
domain	string	Yes	The domain to validate (e.g., example.com).

Output

Name	Type	Required	Description
data	string	Yes	Data from the action execution
error	string	No	Error if any occurred during the execution of the action
successful	boolean	Yes	Whether or not the action execution was successful or not

Verify Email Address

MAILCHECK_VERIFY_EMAIL

Tool to verify provided email address. Use after obtaining user email input.

Input parameters

Name	Type	Required	Description
email	string	Yes	The email address to verify.
accept_role	boolean	No	Whether to accept role-based email addresses (e.g., admin@company.com).
accept_disposable	boolean	No	Whether to accept disposable email domains.

Output

Name	Type	Required	Description
data	string	Yes	Data from the action execution
error	string	No	Error if any occurred during the execution of the action
successful	boolean	Yes	Whether or not the action execution was successful or not