Promptles
GTM & Business Tools

API Key

beginner

Definition

A secret string that identifies your application when it calls an external API: like a password for machines. Most SaaS tools (Stripe, SendGrid, HubSpot) issue API keys through their settings page. You include the key in your requests so the service knows who is calling and what permissions to grant. Never hard-code API keys in your source files; store them in environment variables.

In the wild

To send emails through SendGrid, your script includes an API key in the request header. SendGrid checks the key, confirms your account has sending permissions, and processes the email. If the key is missing or invalid, the request is rejected with a 401 error.

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