OAuth

advancedwidespread

OAuth is an open standard that allows you to grant an application or AI agent limited access to your data stored in another service without sharing your password.

In plain terms

Imagine that at a hotel you do not receive the master key, but a card that only opens your room and the gym, and expires on the day of checkout. OAuth does the same on the internet: an application does not get your password, but a limited, revocable "access card."

This is necessary because the password opens everything. If you gave your Google password to a calendar app, it could read your emails and change your password. With OAuth, the application states in advance what access it needs, for example only to your calendar and only for reading, and you approve or reject this.

In the age of AI agents, this has become particularly important. When an agent organizes emails, searches for files, or books appointments on your behalf, it typically receives permission via OAuth. This means the agent can only do what you have approved, and you can revoke the permission at any time.

How it works

The application or agent indicates what access it requests (for example, "read calendar") and redirects you to the provider where your account is.
You log in there on the provider's own page, so the application never sees your password. On an approval screen, you can see exactly what permissions are requested.
If you agree, the provider issues an access token to the application in the background. This is a long code string valid only for approved operations.
The application presents this token with every request. The token typically expires after a short time. Many services allow reissuing it with a separate refresh token, so you do not always need to re-authorize.
You can revoke permission at any time in your account settings. Afterward, the application cannot obtain a new token, and any token already issued stops working when it expires at the latest. You do not need to change your password in the meantime.

An everyday example

You connect your AI assistant to your Google Calendar: a Google window pops up asking if you allow the application to view and edit your events. By clicking the "Allow" button, you granted OAuth permission, and your password remained with Google throughout.

Who is affected

everyoneWhenever you connect an application or AI agent to your email, calendar, or storage, you grant OAuth permission, so it is worth reading what you are approving.

developerIf you are building an agent or an integration, OAuth is the standard way to securely access external services on behalf of the user. → Code

entrepreneur, executiveThe permissions of agents accessing corporate data can be restricted using OAuth grants. These permissions are visible on the corporate account management interface and can be revoked if necessary.

employeeIf you link your work account to an AI tool, you grant access to company data with your approval, so what you click on matters. → Work & HR

A common misconception

MythOAuth verifies who I am, meaning it is a login system.

In realityOAuth is about what someone can do on your behalf, not about who you are. Behind the "Sign in with Google" button, OpenID Connect, built on OAuth, handles the authentication.

Limits and risks

OAuth is only as secure as your vigilance: if you approve overly broad permissions without thinking, the application or agent legitimately gains access to everything you authorized.
Scammers may ask for permission through a fake login page, or even through an app disguised as harmless that appears on the genuine provider's own site. So always check that you really are on the provider's site, which app is asking for permission, and what permissions it wants.
A token is valuable loot: if it leaks from a poorly protected application, an attacker can act in your name until it expires or is revoked.
OAuth does not check whether an agent uses the permission wisely: a deceived agent can still cause harm within the approved scope.

Similar, but not the same

Authentication – Authentication determines who you are, while OAuth regulates what someone can access on your behalf.
API key – An API key is typically a long-lived secret code that identifies an application and is managed by the developer. An OAuth token, by contrast, is an expiring permission tied to a specific user's approval and scope.
Single sign-on – Single sign-on means you can access multiple systems with one login. This is often implemented via OpenID Connect or other standards built on OAuth. OAuth itself is about granting access, not logging in.

Related concepts

Broader

access rights management, Access control, Cybersecurity

Narrower

Access token, refresh token, Permission scope

On the edge

Authentication, API key, OpenID Connect, Model Context Protocol, Principle of Least Privilege

A brief history

The first version of OAuth was released in 2007 because web services previously asked for users' passwords to access each other. The currently used OAuth 2.0 standard was issued in 2012 by the IETF, the body responsible for internet standards.

Where things stand

OAuth 2.0 is the basic standard for internet access authorization, used by almost every major provider. OAuth 2.1, which consolidates established security best practices, has long been in draft form, but the authorization part of the Model Context Protocol already builds on it. Connecting AI agents to external services typically happens via OAuth, while extensions tailored to agents are still taking shape.

Status: 2026 November

In the news

Appears in 1 Agent Age stories; the curve shows weekly occurrence in the news magazine.

LiteLLM was poisoned using GitHub tokens leaked from Claude Code, attacker saysOct 26, 2026 · Code

Also known as

OAuth · OAuth 2.0 · OAuth 2.1 · Open Authorization · open authorization (OAuth) · OAuth authorization · OAuth authentication · OAuth-token

Sources

This entry was machine-edited and has undergone machine expert review; the “In the news” section updates automatically from Agent Age stories.