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Connect Mailcheck

1 auth method · updated 2026-10-01

Mailcheck is an email verification service that helps businesses validate email addresses to ensure deliverability and reduce bounce rates.

www.usercheck.com/ ↗

API key

Uses your own credential — Verslay stores it encrypted

Connectable today
  1. 1
    Sign in to Mailcheck
    Open https://www.usercheck.com/ and sign in to the account you want to connect.
  2. 2
    Create the API key
    Generate a new API key from the API or developer settings in your Mailcheck dashboard.
  3. 3
    Copy it immediately
    Mailcheck usually shows the full API key only once, right after you create it. Store it somewhere safe before closing the page.
  4. 4
    Connect in Verslay
    In the Verslay Hub, open Connections, find Mailcheck, and paste the API key into the Mailcheck API Key field.
  5. 5
    Verify
    The connection flips to Connected. Run any read-only action once to confirm the credential has the right scopes.
  6. 6
    Rotate safely
    When you rotate later: connect the new credential first, confirm it works, then revoke the old one.

What you’ll paste into Verslay

Mailcheck API Key

The API key used for authenticating requests to the Mailcheck/UserCheck API.

required · secret
Mailcheck website ↗

Mailcheck connection FAQ

How do I connect Mailcheck to Verslay?

Open Connections in the Verslay Hub, find Mailcheck, and use the API key method. The steps are: Sign in to Mailcheck, Create the API key, Copy it immediately, Connect in Verslay, Verify, Rotate safely.

What do I need before I connect Mailcheck?

You need Mailcheck API Key from your Mailcheck account. The API key used for authenticating requests to the Mailcheck/UserCheck API.

Related connection guides

See also Verslay use cases and agents.

Connect Mailcheck once — every agent can use it

Verslay agents share your connections. Connect Mailcheck in the Hub and every use-case that needs it lights up — no per-agent setup.

Open the Hub →
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