Skip to content

APIs and Webhooks · HMAC

HMAC

HMAC is a keyed hash used to authenticate a message such as a webhook body.

What is hmac?

HMAC describes a keyed hash used to authenticate a message such as a webhook body. In reliability work, the label is useful only when it maps to a measurable check, a clear owner, and a next action when expectations break. Without that operational meaning, the phrase becomes decoration in dashboards and status updates.

Why it matters

HMAC matters because teams need a precise shared meaning for a keyed hash used to authenticate a message such as a webhook body. Vague language turns incidents into arguments about words instead of fixes.

When everyone uses the same definition, alerts, status updates, and post-incident reviews stay aligned.

How it works

In practice, a keyed hash used to authenticate a message such as a webhook body shows up as a concrete signal you can measure or communicate. Operators define what good looks like, watch for deviations, and record what happened when expectations break.

The useful version of hmac is operational: it changes who gets notified, what customers see, or which metric a team reviews after an incident.

Practical example

Imagine a team operating around HMAC-SHA256 over the raw webhook body. When observed behavior stops matching the definition of hmac, the team treats that change as a reliability event with a clear owner and next step.

Common misconception

HMAC encrypts the payload so nobody can read it

That reading usually collapses distinct ideas into one slogan. Keep hmac tied to observable behavior so the definition stays useful under pressure.

How Fajita handles this

HMAC authenticates integrity and origin when used with a shared secret. It is not encryption by itself.

Was this definition clear?