Get in touch
Mail OAuth & Email Log for OpenCart 2.3, 3.x and 4.x — store emails through Microsoft 365 and Gmail, with an email log
Mail OAuth & Email Log overview Microsoft 365 connection in the module OpenCart email log One email in the log with the server dialogue
  • OpenCart
  • CRM and integrations
  • v1.0.0

Mail OAuth & Email Log for OpenCart 2.3, 3.x and 4.x — store emails through Microsoft 365 and Gmail, with an email log

Your OpenCart store sends email through your Microsoft 365 / Outlook.com or Google Workspace / Gmail mailbox with OAuth sign-in and no password, or through any SMTP server. The log records every email with the server answer. Pro adds retries, background sending, a backup connection, resending, alerts, Brevo, Mailgun, Postmark and SendGrid. Perpetual licence.

Pro · lifetime licence The more sites, the less each one costs
Compatibility
OpenCart 4.0.2.3+ and 4.1.x (tested on 4.0.2.3 and 4.1.0.3), 3.x (tested on 3.0.3.8 and 3.0.5.0), 2.3.0.2 · PHP 7.0+ · a separate build for each line · interface: English, Ukrainian, Russian
Version
v1.0.0 (OpenCart 4)
v1.0.0 (OpenCart 3.x)
v1.0.0 (OpenCart 2.3)
Licence
two sites, lifetime
Trial
7 days, no card, one per site
Updated
October 2026
Or all 177 Pro modules with All Access — 4 990 ₴ / year

What Free has,
and what Pro adds

The free version works with no time limit. Pro adds the rest of the features in the table.

Feature Free Pro
Microsoft 365 / Outlook.com with OAuth sign-in: through the Microsoft Graph API or SMTP XOAUTH2 ✔ ✔
Google Workspace / Gmail with OAuth sign-in: through the Gmail API or SMTP XOAUTH2 ✔ ✔
Any SMTP server with a login and password (STARTTLS or SSL) ✔ ✔
Store mail settings through the module's own client, with exact errors ✔ ✔
The app lives in your own Microsoft Entra or Google Cloud, with on-screen instructions ✔ ✔
Log of every email: recipient, subject, content, attachments, order, server answer ✔ ✔
Server dialogue for failed and test emails, with passwords hidden ✔ ✔
Search and filter by status, address, subject, order and date; delete and log retention ✔ ✔
Test email with the full dialogue ✔ ✔
A mail error does not break the checkout: the email goes to the log with its status and reason ✔ ✔
Connection health: token state, errors with hints, a 30-day reminder before a Microsoft client secret expires, a warning about a different mailbox ✔ ✔
Secrets and tokens are encrypted ✔ ✔
Automatic retries after 5, 15, 60 minutes, 3 and 12 hours — ✔
Emails wait up to 3 days for a new mailbox sign-in and go out after it — ✔
Background sending: the customer does not wait for the mail server — ✔
Backup connection: on a failure the email goes through the store mail settings — ✔
Resend from the log, one by one or selected — ✔
Telegram and email alerts: a new sign-in is needed or an email finally failed — ✔
Brevo, Mailgun, Postmark and SendGrid through their APIs — ✔
Microsoft application permission without a mailbox sign-in — ✔
CSV export of the log — ✔

What it looks like

Mail OAuth & Email Log overview
Overview: how email goes out, counters, a test email and the server check. Test store.
Microsoft 365 connection in the module
Microsoft 365 connection: sending method, app, mailbox and redirect URI.
OpenCart email log
Log: every email with its status, service and error. Test data.

Key points

What the store owner gets

All OpenCart email goes through the chosen connection: orders, registration, password reset, the contact form, email from the admin and other extensions.

Connecting the mailbox

The app is created in your own Microsoft Entra or Google Cloud, with step-by-step instructions on the screen.

Email log

The log shows who an email went to, when and through what, whether the server accepted it and which order it belongs to.

The trial starts when you ask

A fresh install is the free version, nothing switches on by itself. The “Try Pro for 7 days” button → e-mail → the key right in the window and by e-mail.

One key — two sites

Moving the store? Unbind the licence on the old domain and activate it on the new one yourself. For studios — keys for 5 or 25 sites, or unlimited.

Technical requirements

  • OpenCart 4.0.2.3+ and 4.1.x, 3.x or 2.3.0.2 · PHP 7.0+ with cURL and OpenSSL.
  • Microsoft: an app in Microsoft Entra, sometimes with the consent of the organization admin.
  • Google: a Google Cloud project with an OAuth app In production.
  • Retries: add a hosting cron job every 5 minutes. Without it the queue is checked during site visits.

Version history

v1.0.0 Current October 2026

For OpenCart 4.x, 3.x and 2.3: Microsoft 365, Google, SMTP, email log, test email, connection health.

Frequently bought with Mail OAuth & Email Log for OpenCart 2.3, 3.x and 4.x

4 modules in one order — 40% cheaper than separately

“Store starter” bundle Mail OAuth & Email Log Nova Poshta Premium LiqPay Telegram notifications and Viber/SMS for customers Need more — all 177 modules in All Access for 4 990 ₴.
3 790 ₴ lifetime instead of 6 260 UAH bought separately
Buy the bundle →

Full module description

Mail OAuth & Email Log for OpenCart sends your store email through your Microsoft 365 / Outlook.com or Google Workspace / Gmail mailbox with OAuth sign-in and no mailbox password, or through any SMTP server. Every email goes to the log together with the server answer.

What the store owner gets

All OpenCart email goes through the chosen connection: orders, registration, password reset, the contact form, email from the admin and other extensions. Nothing changes in the OpenCart mail settings. Turn the module off and the store sends mail as before.

Connecting the mailbox

The app is created in your own Microsoft Entra or Google Cloud, with step-by-step instructions on the screen. Then you press Connect and sign in to the mailbox. The module refreshes the sign-in itself and warns you ahead of a Microsoft client secret expiry.

Email log

The log shows who an email went to, when and through what, whether the server accepted it and which order it belongs to. You can search and filter by status, address, subject, order and date.

An opened email shows its content, attachments and the server answer. Test and failed emails also have the full server dialogue with passwords hidden. When an email did not go out, you see the exact reason.

When mail fails (Pro)

On a temporary error the email is tried again after 5, 15, 60 minutes, 3 and 12 hours. If the mailbox lost its sign-in, emails wait up to 3 days and go out after you reconnect, with no attempts used. If the main connection is down, the email goes through the store mail settings. The owner gets a Telegram or email alert.

How it works, step by step

  1. OpenCart prepares an email and the module takes it over.
  2. The email is written to the log and goes through the chosen connection.
  3. The log keeps the server answer or the error with a hint.
  4. The checkout does not depend on mail: an error does not break it.

Under the hood

  • The store mail settings are not rewritten: the module turns on for the request only.
  • Secrets and tokens are encrypted.
  • Uninstalling removes the tokens.

Installation

  1. Extensions → Installer: upload the archive for your version without renaming the file. OpenCart 2.3 without FTP: copy upload/ to the store root.
  2. OpenCart 2.3: Extensions → Modifications → Refresh.
  3. Extensions → Modules → Mail OAuth & Email Log → Install → Edit.
  4. Choose the connection, save, press Connect and send a test email.
  5. For Pro: paste the key or start the 7-day trial.

Questions
about the module

Didn't find the answer? Message us on Telegram and we'll reply within a business day.

@catcode_support Setup, compatibility, activation
My store sends email through Microsoft 365 with a login and password. What should I do?

Microsoft has announced the retirement of password sign-in for SMTP AUTH in Exchange Online. Connect the same mailbox with OAuth sign-in: no password is needed or stored.

Graph or SMTP for Microsoft 365?

Graph is recommended: it only needs the Mail.Send permission. SMTP XOAUTH2 requires Authenticated SMTP to be enabled for the mailbox.

Google stops sending after a week.

The Google Cloud app is in Testing: Google ends such a sign-in after 7 days. Move the app to In production and connect again.

Does Sent mean the customer received the email?

It means the mail service accepted the email. The module cannot see whether it landed in spam. Errors the service returned right away are shown in the log with their exact text.

Where is email content stored?

Only in your OpenCart database, for as many days as you set. You can turn content storage off, then only the address, subject and status are kept.

Does anything change in the OpenCart mail settings?

No. The module rewrites nothing in System → Settings → Mail. Turn the module off and OpenCart sends mail as before.

What if the store already has another mail extension?

Two extensions should not manage mail at the same time. We have not tested it alongside other mail extensions, so keep one.

OpenCart 2.3 does not install the archive.

The 2.3 installer copies files over FTP. Without FTP, copy the upload/ folder from the archive to the store root. Refresh modifications after installing.

Is this an official Microsoft or Google module?

No. The module is made by CatCode studio; Microsoft and Google are trademarks of their owners.

Not quite what you are looking for?

We build custom modules for WordPress, WooCommerce, OpenCart and Shopify. Tell us about the task and we'll prepare an estimate.

Order a custom module