Guide

Gmail OAuth scopes explained

The permission screen says "Read, compose, and send emails from your Gmail account." Here's what that sentence maps to, how Google grades it, and what an app has to go through before it can ask you.

By the Synced team · Updated

In short

Gmail OAuth scopes are the named permissions an app requests to use your Gmail data, such as gmail.readonly (view messages and settings) or gmail.send (send only). Google sorts scopes into non-sensitive, sensitive, and restricted. Most Gmail scopes, including gmail.readonly and gmail.modify, are restricted, which means an app serving the public must pass Google's verification and, if it handles the data on its own servers, an annual CASA security assessment. You can review and remove any app's access at myaccount.google.com/permissions.

What a Gmail scope is, in one paragraph

When an app asks to connect to your Google Account, it sends Google a list of scopes: strings like https://www.googleapis.com/auth/gmail.readonly, each granting one kind of access. Google's consent screen turns them into plain sentences. The general idea is covered in the OAuth scopes glossary entry. This guide is the Gmail-specific version: every scope, Google's own description, and the review each one triggers.

Google's three scope categories: non-sensitive, sensitive, restricted

Google grades every scope by how much user data it exposes. The grade decides how much review a developer has to pass before strangers can grant the scope. Apps that skip review show an "unverified app" screen and are capped at 100 new users in total.

CategoryWhat Google says it coversWhat the developer has to do
Non-sensitiveNarrow access, such as managing labels or acting only inside an add-on you're usingNo sensitive or restricted scope review
SensitiveAccess Google reviews before any account can grant it. Google's examples include reading Calendar events and storing a new contactA written justification for each scope, an explanation of why a narrower scope won't work, a demo video of the consent flow, a verified domain, and a public privacy policy. Google says this typically takes 3 to 5 business days
Restricted"Wide access to Google user data"Everything required for sensitive scopes, proof the app is a permitted application type, and, for apps that access the data through their own servers, a CASA security assessment by a Google-approved assessor, repeated at least every 12 months

Summarized from Google's sensitive and restricted scope verification pages. Exceptions apply for personal-use, testing, and internal Workspace apps.

Every Gmail API scope and what it allows

All Gmail scopes start with https://www.googleapis.com/auth/ except the full-access one, which is https://mail.google.com/. Descriptions below are Google's own wording.

ScopeGoogle's descriptionCategory
gmail.labelsSee and edit your email labels.Non-sensitive
gmail.addons.current.action.composeManage drafts and send emails when you interact with the add-on.Non-sensitive
gmail.addons.current.message.actionView your email messages when you interact with the add-on.Non-sensitive
gmail.addons.current.message.metadataView your email message metadata when the add-on is running.Sensitive
gmail.addons.current.message.readonlyView your email messages when the add-on is running.Sensitive
gmail.sendSend email on your behalf.Sensitive
gmail.metadataView your email message metadata such as labels and headers, but not the email body.Restricted
gmail.readonlyView your email messages and settings.Restricted
gmail.composeManage drafts and send emails.Restricted
gmail.insertAdd emails into your Gmail mailbox.Restricted
gmail.modifyRead, compose, and send emails from your Gmail account.Restricted
gmail.settings.basicSee, edit, create, or change your email settings and filters in Gmail.Restricted
gmail.settings.sharingManage your sensitive mail settings, including who can manage your mail.Restricted
https://mail.google.com/Read, compose, send, and permanently delete all your email from Gmail.Restricted

Two things stand out. First, gmail.send is only sensitive, which fits: an app that can send but not read never sees your existing mail. Second, gmail.metadata is restricted even though it excludes message bodies, because headers alone reveal who you talk to and when. The one scope to be wary of is https://mail.google.com/: it's the only Gmail scope that includes permanent deletion, and few apps that read and draft email need it.

What the CASA security assessment involves for restricted scopes

CASA stands for Cloud Application Security Assessment, the framework Google uses to standardize its reviews. If an app reads restricted Gmail or Drive data from or through a server it runs, a Google-approved third-party assessor has to evaluate it. The app must recertify at least every 12 months after the assessor's Letter of Assessment approval date.

Google lists four exceptions to verification: apps for personal use by you or a few people you know, apps in development with a limited set of test users, service accounts that only touch data the service owns, and apps used only inside one Google Workspace organization. In practice, a public app that asks for gmail.readonly without an unverified-app warning has been through Google's review. It doesn't tell you how the vendor behaves beyond what Google checks, which is why the vendor's own policies still matter.

Other Google scopes that often come with Gmail access

Email assistants rarely stop at Gmail. These are the Drive, Calendar, Contacts, and identity scopes you'll see alongside it.

ScopeWhat it allowsCategory
drive.readonlyView and download all your Drive files.Restricted
drive.fileCreate or modify only files you open with the app or share with it through a file picker.Non-sensitive
calendarSee, edit, share, and permanently delete all the calendars you can access using Google Calendar.Not on Google's restricted list. Reading Calendar events is Google's own example of a sensitive scope
contacts.readonlyRead the contacts saved in your Google Contacts.Not on Google's restricted list
contacts.other.readonlyRead your "other contacts", the people you've interacted with who aren't saved as contacts.Not on Google's restricted list
userinfo.email, userinfo.profileSee your email address and basic profile info.Basic sign-in scopes

Limited Use: the rules attached to Gmail data

Scopes decide what an app can reach. Google's API Services User Data Policy decides what the app may do with it. The Limited Use requirements say apps may use sensitive and restricted data only to provide or improve user-facing features that are prominent in the app. They can't sell or transfer it to ad platforms or data brokers, and staff may read it only with your agreement, for security investigations, for legal reasons, or in aggregated form.

Google's Workspace API policy adds an AI rule: developers may not use the data to create, train, or improve a machine-learning or AI model beyond that specific user's personalized model. If a vendor's privacy policy doesn't mention Limited Use, ask why.

How to see and revoke what apps can access your Gmail

  1. 1
    Open your Google Account connections

    Go to myaccount.google.com/permissions while signed in to the account you want to check.

  2. 2
    Filter to apps with account access

    Choose Access to your Google Account.

  3. 3
    Open an app and read its permissions

    Select the app, then See details. Google lists what it can access, in the same language as the consent screen.

  4. 4
    Remove what you don't use

    Select Remove access, then Confirm. The app loses access to your account right away. Data it already copied is governed by that vendor's retention policy, so check it or request deletion.

On a Google Workspace account, your admin may already decide this for you. In the Admin console under Security, Access and data control, API controls, admins can mark apps as trusted, limited, or blocked, and can restrict high-risk Gmail and Drive actions such as sending mail or deleting files.

The Google scopes Synced requests, and what each is used for

Synced, the AI inbox assistant, lists its Google scopes in its privacy policy and has completed Google's restricted-scope verification, including the CASA security assessment. Drive, Calendar, and Contacts scopes apply when you connect those services.

ScopeCategoryWhat Synced uses it for
gmail.readonlyRestrictedSearch messages, read message details and headers, and summarize threads
gmail.modifyRestrictedCreate drafts and send emails you've approved
gmail.settings.basicRestrictedRead and update your Gmail out-of-office auto-reply when you set it from Synced
drive.readonlyRestrictedSearch and read Drive files for context, like finding the file an email asks for
calendarNot restrictedRead availability and create or modify events
contacts.readonly, contacts.other.readonlyNot restrictedAutocomplete invitees through the People API
userinfo.email, userinfo.profileBasicIdentify the connected account
The scope allows sending. The product asks first.

Google describes gmail.modify as "Read, compose, and send emails." Nothing in the scope itself requires your approval. Synced's rule that every AI-drafted message waits in Decide until you approve it is a product decision on top of the permission. Security details are on the Security page.

Questions

Frequently asked.

What's the difference between gmail.send and gmail.modify?

gmail.send can only send mail and is classed as sensitive. gmail.modify can also read messages and manage drafts, so it's restricted. An app that reads threads and prepares drafts for you needs read access plus draft access, which gmail.send doesn't provide.

What does "Google hasn't verified this app" mean?

The app requests sensitive or restricted scopes and hasn't completed Google's verification. Unverified apps are capped at 100 new users. It can be legitimate (a developer testing, or an internal tool), but for a public product it's a reason to stop and ask.

Does removing an app's access delete my data?

No. Revoking access at myaccount.google.com/permissions stops future access. Anything the app already stored is covered by its own retention policy, so request deletion from the vendor if you want it gone.

Is gmail.readonly safer than gmail.modify?

It can't send, draft, or change labels, so the damage from misuse is smaller. It still exposes every message body, which is why Google classifies both as restricted.

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