Mailbox apps

Send documents from Gmail and Outlook without downloading them

Conterminal Mail is a Chrome extension for Gmail and Outlook on the web. It puts a launcher in your mail toolbar so you can send the attachments on an email straight into Document Review — no download, no re-attach, no forwarding step.

11 minute setup · Updated July 26, 2026

This is not a mailbox monitor.

The extension does nothing until you open it. It never reads message bodies, never changes labels or read state, never moves or deletes mail, and does not watch your mailbox in the background. Each time you open the panel it reads only the conversation IDs of the emails you have selected or opened right then.

What the extension does

After install, a small Conterminal button appears in your mail toolbar. In Gmail it sits in the right-side utility toolbar, just before the Google Apps and account controls. In Outlook Web it sits immediately to the left of the settings button. Its label is Open Conterminal.

Clicking it opens a compact dropdown anchored under the button — about 400 pixels wide — titled Mail to Conterminal. That dropdown is the whole product. There is no Chrome side panel to open and no toolbar icon to pin. Close it with its × button, by clicking the launcher again, or with Escape.

Inside, you get one card per selected conversation, one row per eligible attachment, a document type for each file, and a Send selected to Conterminal button. Sent files land in Document Review exactly as if they had arrived through the email intake address. When every file in a send succeeds, the panel closes itself about a second later.

The extension has no access to Conterminal on its own. It proves who your mailbox is to the Conterminal server, and the server decides which workspace the documents belong to. If your mailbox is not tied to an active Conterminal user, nothing can be sent.

Before you install

Check your Chrome version. The extension requires Chrome 116 or newer. It runs in Chrome only — not Firefox, not Safari, and not the Outlook desktop or mobile apps.
Confirm your mail host. The launcher is injected on exactly three hosts: mail.google.com, outlook.office.com, and outlook.cloud.microsoft. A custom vanity mail domain that does not resolve to one of those hosts will not show the launcher.
Confirm your Conterminal access. You need an active Conterminal user with at least one active workspace membership. A revoked user, a disabled mailbox integration, or a user with no active workspace fails at preview time, not at install time.
Decide which mailbox you will use. The extension identifies you by the mailbox you authorize, not by your Chrome profile. If you work several mailboxes, authorize the one whose address matches your Conterminal login.

What it needs: Read-only access to the messages you explicitly select, permission to run its ID-only selection reader in the mail tab after you open it, and HTTPS access to Conterminal and the document-intake service.
What it never touches: Message bodies, labels, folders, read/unread state, drafts, sending, deletion, and any conversation you did not select. It has no background timer and no mailbox sync.

Install Conterminal Mail

Install only from the Chrome Web Store. The store assigns the extension its permanent ID, and both the Google and Microsoft OAuth registrations are bound to that ID. A sideloaded copy of the source folder gets a different ID and cannot authorize.

Open the Chrome Web Store listing for Conterminal Mail. Ask Conterminal Support for the current listing link if your administrator has not sent one.
Select Add to Chrome and review the site-access list Chrome shows you.
Confirm the install. You do not need to pin anything to the Chrome toolbar — the extension's only surface is the in-page launcher.
After install, Chrome opens or focuses a Gmail tab and opens the Conterminal panel for first-run setup. If you already had Gmail or Outlook Web tabs open, the launcher is injected into them too, so you do not need to reload the inbox.

What the Chrome permission prompt lists

Chrome lists site access for the two Outlook Web hosts, mail.google.com, the Conterminal application origin, the Conterminal document-intake service, graph.microsoft.com, and login.microsoftonline.com. That list looks broader than the extension's actual reach, so it is worth knowing why each entry is there.

The mail hosts: Used to render and position the launcher, and — only after you open the panel — to read the IDs of the conversations you selected. Message contents are read afterwards through the provider's own read-only API, not from the page.
The Microsoft hosts: graph.microsoft.com resolves your selected Outlook conversations and downloads confirmed attachment bytes. login.microsoftonline.com completes the sign-in code exchange.

Chrome cannot describe “reads only what you select” in its permission prompt, so the wording for the mail hosts is broad by design. If your security team asks, the content script that runs on the page reads accessibility state and opaque conversation identifiers only; it has no code path that touches message bodies or attachment bytes.

Managed deployment

An administrator can force-install and pin a reviewed version for managed users through Chrome policy, which is the recommended path for an operations team that should all be on the same build. Pin the reviewed version rather than allowing automatic upgrades if your change process requires it. The installed version is always visible in the panel footer, shown as v1.0.14 or similar — quote that number when you contact support.

Chrome extension policy for administrators

Connect Gmail

The first time you open the panel in Gmail you get a one-time setup screen headed Connect Gmail, with this text: “Reads only the email details and attachments you choose. Nothing is sent until you click Send, and your Gmail is never changed.”

Select Connect Gmail. The button changes to Connecting... while Google's consent window is open.
Choose the Google account whose mailbox you are working, then approve both requested permissions.
When the consent window closes, the panel loads your current selection and the account chip in the header changes from Not connected to your mailbox address.

Exactly two Google scopes are requested, and both are mandatory:

gmail.readonly: Reads the message headers and attachment metadata for the conversations you selected, and lets Conterminal retrieve the bytes of the attachments you confirm. It cannot send, label, move, or delete anything.
userinfo.email: Confirms which mailbox address authorized the extension. That address is what Conterminal matches to your user account.

If you clear either checkbox on Google's consent screen, the connection is rejected outright and the panel says “Connect again and approve both permissions.” The half-granted token is discarded, so retrying is safe — you just have to approve both.

Two other Gmail failures are worth recognizing. If your Chrome profile is not signed in to a Google account at all, the panel says “Sign in to Google in Chrome, then try connecting again.” If you close or decline the consent window, it says “Gmail wasn’t connected. Try again.”

You are not asked to reconnect on every visit. Each time the panel opens it silently rechecks Chrome's live token cache. The extension stores only a connection timestamp and the names of the granted scopes; the live cache — not that stored record — decides whether you are still connected.

Connect Outlook Web

Outlook Web uses the same panel with an equivalent Connect Outlook button. Unlike Gmail, there is no automatic first-run prompt: open the launcher yourself and select Connect Outlook.

Sign-in is an authorization-code flow with PKCE against Microsoft identity. No client secret is used and no refresh token is issued, which is why an Outlook session lasts only as long as the panel does. The flow requests five delegated scopes: openid, profile, email, User.Read, and Mail.Read. If User.Read or Mail.Read is missing from what Microsoft returns, the panel says “Connect again and approve both permissions.”

The Entra prerequisite your IT admin must satisfy

Outlook will not connect at all until the Microsoft Entra application is registered correctly. Two things are required, and both are administrator work:

A single-page-application redirect URI. It must be registered as an SPA redirect URI — not Web, not Public client — with exactly this shape: https://<stable-extension-id>.chromiumapp.org/microsoft. The <stable-extension-id> segment is the extension's Chrome Web Store ID, and the /microsoft path suffix is required. A redirect URI registered under the wrong platform type is the most common cause of a connection that fails immediately.
Delegated Microsoft Graph permissions. Grant delegated User.Read and Mail.Read. Do not grant application permissions and do not grant write scopes — the extension has no code path that sends, moves, or deletes mail.

If the Microsoft client ID was not configured into the build, the Outlook panel does not fail at sign-in — it fails on open, with “This version isn’t ready. Ask your administrator to reinstall it.” That message means a build or registration problem, never a mailbox problem, so do not spend time on your Outlook account.

Microsoft app registration guide Microsoft Graph permissions reference

Link your Conterminal account

Authorizing your mailbox proves who the mailbox is. It does not yet tell Conterminal who you are. If the authorized mailbox address matches exactly one Conterminal user who is active and belongs to at least one active workspace, the two are linked automatically and you go straight to the attachment list. Otherwise the panel shows a Link your account step.

Enter your Conterminal email. The field is labeled Conterminal email and is prefilled with your mailbox address. Change it if you sign in to Conterminal under a different address. Select Send link.
Open the email. The panel switches to Check your email and reads “Open the email sent to your address and click ‘Continue to Conterminal.’” The link is valid for 15 minutes.
Come back to the mail tab. Following the link signs you in and drops you on Document Review. When you switch back to the mail tab, the panel rechecks the link on its own. If it has not caught up, select Check link status.
Fix a wrong address. Select Use a different email to clear the field and start over.

“Link sent.” does not mean an email was sent.

The panel reports success and moves to Check your email in three different situations: when the email really was sent; when the address you typed does not belong to any Conterminal user, in which case the server deliberately stops without sending anything; and when a cooldown suppressed the send — the same mailbox and address within the last five minutes, or five link requests from that mailbox within the last hour. All three look identical in the panel. If no email arrives, do not keep pressing Send link. Confirm the exact address you use to sign in to Conterminal, wait five minutes, and try once more; if it still does not arrive, contact support rather than burning through the hourly allowance.

While you are waiting, Check link status reports “Still waiting. Open the email link, then check again.” That message is honest: it means Conterminal still sees no link, and it is the signal to suspect a typo or a suppressed send rather than a slow inbox.

Send attachments

Select the emails. Use the checkboxes in the message list, or simply open one message. The panel picks up the checked rows first and falls back to the open conversation. If nothing is selected, it shows Choose an email and “Select an email with its checkbox, or open an email.”
Open the launcher. Leave the panel open while you work — it refreshes the attachment list automatically as you change the selection in the mail list behind it.
Pick the workspace. A Conterminal workspace dropdown appears only if you belong to more than one workspace. With a single workspace it is chosen for you and stays hidden. With several, the Send button stays disabled until you choose one.
Set the document type per file. Every row has its own Document type selector offering Delivery Order, Proof of Delivery, and Other Document. Conterminal pre-selects a suggestion from the file name and the subject line: wording like proof of delivery, delivery receipt, or POD becomes Proof of Delivery; delivery order, delivery release, or customs delivery becomes Delivery Order; an invoice, packing list, or bill of lading becomes Other Document; and a PDF that matches nothing defaults to Delivery Order. The suggestion is a guess; you are responsible for the value you send.
Uncheck what you do not want. Every eligible file starts checked. The counter above the list shows something like 4 files · 3.2 MB, and switches to a limit-style readout such as 21/25 conversations once you pass 80% of any cap.
Send. Select Send selected to Conterminal. The button becomes Sending... and every row shows a Sending chip.

Reading the result

Results are reported per file, not per send. Each row ends with one of these chips:

Sent: Accepted and queued into Document Review. The row is locked and its checkbox is disabled.
Already received: Conterminal already has this exact attachment. Duplicate sends are collapsed rather than creating a second review item.
Failed: Not accepted. The row stays checked with a reason underneath so you can fix it and send again without reselecting.
Over 20 MB / Size unknown: Blocked before sending. These rows are unchecked and locked; the file cannot go through the extension.

A summary notice appears above the list, for example “Done — 3 sent, 1 already in Conterminal.” If nothing was rejected, the panel closes itself about a second later. If anything was rejected, it stays open with the failures still selected. Sent documents then follow the normal Document Review queue; the extension's job ends at the handoff.

Your mailbox is never modified. The source message keeps its labels, its folder, and its read state, and no reply or forward is created on your behalf.

Limits and supported files

The panel enforces these caps before it will send, and the Conterminal server re-checks all of them. Crossing one does not partially send — the whole button stays disabled until you trim the selection.

Limit	Cap	What you see
Conversations per send	25	Selecting more fails before the panel opens: “Select no more than 25 Gmail conversations.” The message names Gmail in Outlook Web too.
Attachments per send	50	“Select no more than 50 attachments.”
Attachments from one message	20	“Select no more than 20 attachments from one Gmail message.” The message names Gmail in Outlook Web too.
Single file size	20 MB	An Over 20 MB chip and “This file is over 20 MB.” The row is unchecked and locked.
Total size per send	100 MB	“Selected attachments exceed the 100 MB total limit.”
Accepted file types	.pdf, .jpg, .jpeg, .png, .tif, .tiff	Anything else is filtered out of the list before you see it.

What silently will not appear in the list

The panel shows only files it can actually send, and it does not explain each omission row by row. If an attachment you expected is missing, it is almost always one of these:

Inline images: Signature logos and images pasted into the body are excluded. In Gmail an attachment is treated as inline when its Content-Disposition is inline, or when it carries a Content-ID without an explicit attachment disposition.
Unsupported extensions: Office files, ZIP archives, CSVs, EMLs, and everything else outside the six accepted extensions are dropped from the list entirely.
Outlook item and cloud attachments: Only true file attachments are listed. A forwarded message attached as an item, and a OneDrive or SharePoint link attachment, are both skipped.
Very long Outlook threads: A conversation is resolved through at most 50 messages and four pages of Microsoft Graph results, so an unusually long thread may not surface every historical attachment.

A Word delivery order cannot be sent through the extension. The Conterminal server will accept a Delivery Order as PDF, DOC, or DOCX, but the extension's attachment list only ever admits PDF, JPEG, PNG, and TIFF — so a .docx delivery order simply never appears as a row. Save it as PDF first, or use the email intake address instead.

The extension offers only three document types. Conterminal also recognizes an Equipment Interchange Receipt, and for Gmail the server will even suggest that type from the file name and subject — but the dropdown has no EIR option, so the suggestion is silently downgraded and the row arrives as Other Document. Reclassify it in Document Review. Outlook uses a shorter version of the same suggestion rules and never proposes an EIR at all.

A conversation with nothing eligible still gets a card, so you can tell it was read: Gmail shows “No supported non-inline attachments were found.” and Outlook shows “No attachments found.”

What Conterminal keeps

Stored by the extension: The conversation IDs captured for the current tab, held in session storage and cleared with the browsing session, plus a Google connection timestamp and the granted scope names. Nothing else.
Never stored by the extension: OAuth tokens, message bodies, and attachment bytes. Google authorization lives in Chrome's own token cache; Microsoft tokens exist only in the panel's memory while it is open, with no refresh token and no client secret.

The two providers fetch bytes differently, and the difference matters for a security review. For Gmail, the extension sends only identifiers; Conterminal re-resolves the message and attachment metadata itself and retrieves the bytes server-side. For Outlook, Conterminal re-resolves the metadata, issues a signed capability that expires after five minutes, and the extension downloads only those confirmed attachments from Microsoft Graph and posts them directly to the intake service. Your Microsoft tokens are never sent to that intake service.

Provider access tokens, message bodies, and attachment bytes are excluded from application and worker logs and from error-reporting context. What Conterminal retains for a submission is provider provenance, the immutable message and attachment identifiers, and the message headers needed to send a threaded confirmation reply. The email body is never sent to or stored by Conterminal.

Troubleshooting

The Conterminal launcher never appears

The launcher is only inserted when it can find a verified seam in the mail toolbar; if it cannot, it stays hidden rather than floating over your mail controls. Reload the tab. If it still does not appear, confirm the tab is on mail.google.com, outlook.office.com, or outlook.cloud.microsoft, and that the extension is enabled at chrome://extensions.

“Could not read the current Gmail selection. Close and try again.”

The panel opened but the selection reader did not return. Close the panel, click somewhere in the message list to re-establish the selection, and open it again. The Outlook wording is “Could not read the current Outlook selection. Close and try again.”

“Select an email with its checkbox, or open an email.”

Nothing is currently selected. Tick a checkbox in the list or open a single message. If a message is open and you still see this, Gmail did not expose a stable thread ID for it — reopen the message from the list rather than from a notification or a search preview.

“This Conterminal mail window has expired. Open it again.”

The panel session is bound to a capability that lasts ten minutes. This is normal after leaving the panel open and walking away. Close it and open the launcher again; nothing was lost. Closing an expired panel produces the same sentence with a capital M — “This Conterminal Mail window has expired. Open it again.” — and means the same thing.

“Your connection expired. Connect again.”

Your provider authorization was rejected. The extension drops the cached authorization and returns you to the Connect screen. Select Connect Gmail or Connect Outlook and approve again.

“Connect again and approve both permissions.”

One of the required permissions was not granted. For Google that means gmail.readonly and userinfo.email; for Microsoft it means User.Read and Mail.Read. Reconnect and leave every checkbox on the consent screen selected.

“Sign in to Google in Chrome, then try connecting again.”

The Chrome profile itself is not signed in to Google. Sign in to the profile, then reconnect. This is separate from being signed in to Gmail in a tab.

“This version isn’t ready. Ask your administrator to reinstall it.”

The installed build is missing its Conterminal API origin or its Microsoft client ID. This is a packaging or registration problem, not an account problem. Send your administrator the version number from the panel footer and reinstall from the Chrome Web Store.

“Still waiting. Open the email link, then check again.”

Conterminal has not seen the link completed. Check the inbox of the exact address you entered, including spam. If no email is there, assume the address is wrong or a cooldown suppressed the send rather than assuming the email is slow.

“This mailbox integration is not active.”

Your mailbox is linked, but the integration account, your Conterminal user, or your workspace membership is disabled. An administrator has to restore access; reconnecting will not fix it.

“Conterminal did not return a valid result for this attachment. Retry it.”

The send completed but Conterminal did not report a usable outcome for that specific file, so it is deliberately marked failed rather than assumed sent. The row stays checked — send it again and check Document Review for a duplicate.

“Conterminal isn’t responding. Reload your mail tab.”

The panel lost contact with the extension's background worker, usually after a Chrome update or an extension reload. Reload the Gmail or Outlook tab and open the launcher again.