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MailInsightX Developers

Getting Started

API Reference

Changelog

Last updated September 10, 2026

Authentication

Creating an API key

  1. Sign in to your MailInsightX dashboard and open the API Keys section (requires a paid plan).
  2. Click Generate Key, give it a name (e.g. "Production Backend").
  3. Your full API key is shown once, immediately after creation, with a copy button. Save it now - MailInsightX never displays the full key again.
  4. After that, only a short prefix (e.g. mi_ab12...) is shown in your key list, enough to identify which key is which without exposing the secret value.

You can have up to 10 active keys per account at a time. Revoke a key you no longer need before creating a new one if you're at the limit.

Warning

A revoked key cannot be un-revoked. If you need it again later, generate a new one.

Authenticating a request

Every API key looks like mi_ followed by 64 hexadecimal characters. Send it in one of these two ways:

Header x-api-key:

GET /v1/balance HTTP/1.1
Host: mailinsightx.com
x-api-key: mi_your_full_api_key_here

Or Authorization: Bearer:

GET /v1/balance HTTP/1.1
Host: mailinsightx.com
Authorization: Bearer mi_your_full_api_key_here

Tip

The Authorization: Bearer form is only recognized as an API key if the token itself starts with mi_. A bearer token that doesn't start with mi_ is treated as a dashboard session token instead, not an API key.

What API keys can and can't access

API keys are strictly scoped to the endpoints documented in this portal (everything under /v1/*). They cannot be used to access any dashboard/account-management endpoint - authenticating with an API key against anything outside /v1/* is rejected the same way an unauthenticated request would be. This is enforced at the authentication layer itself, not by individual endpoint checks.

Example: your first request

curl -H "x-api-key: mi_your_full_api_key_here" https://mailinsightx.com/v1/ping
{ "message": "pong" }