The OpenCart playbook

OpenCart sends the order mail. Your domain still has to earn the inbox.

OpenCart has no sending infrastructure: it uses PHP mail() on your web host or an SMTP server you choose, and its docs recommend SMTP. SPF and DKIM sit outside OpenCart, and nothing warms the domain. Get it authenticated, keep your store as it is, and add the domain here so we build its reputation while OpenCart keeps sending.

Start warming my domainSee guided DNS
The OpenCart playbook

Keep sending from OpenCart. Warm the domain here.

Step 1

Choose the mail engine deliberately

Under System > Settings > Mail, OpenCart sends either with PHP mail() on your web host or over SMTP, and its docs recommend SMTP as more reliable and less likely to be flagged as spam. In some OpenCart 4 releases a fresh install leaves the engine empty, and order email only goes out once one is set.

Step 2

Publish SPF and DKIM for whoever delivers

OpenCart publishes no DNS records. Its docs say SPF and DKIM sit outside OpenCart but are essential, and are the first thing to check when mail lands in spam. The records to publish are those of your web host or your SMTP provider.

Step 3

Add your brand domain to Inbox Boost

Use the domain in your From address, yourstore.com. We set up what it needs and build its sender reputation. Nothing to connect to OpenCart: no API key, no extension, no change to your store.

Step 4

Keep order mail and newsletters running in OpenCart

Marketing > Mail sends newsletters through the same engine as order confirmations, so both go out from yourstore.com. Mailbox providers score the domain in your From address, so the reputation built here counts for every OpenCart send from yourstore.com.

Step 5

Check where OpenCart mail lands

Inbox placement tests show whether your order mail and newsletters reach Primary, Promotions or Spam across the major mailbox providers, and blacklist monitoring keeps watching the domain once it is warm.

  • Nothing to connect: no OpenCart extension, API key or admin login
  • Nothing to change: your mail engine, templates and newsletters stay as they are
  • PHP mail() or SMTP: it works either way, because the reputation belongs to the domain
  • Watched after warmup: blacklist and authentication monitoring on your brand domain
Features OpenCart senders lean on

The parts of the platform this plan leans on.

Feature

Inbox Boost

Add a domain. We provision the sending server and publish your DNS.

Learn more Feature

Guided DNS setup

We write SPF, DKIM and return-path into your zone, not you.

Learn more Feature

Inbox placement testing

See whether you land in Primary, Promotions or Spam across providers.

Learn more
See it play out

A OpenCart domain, warmed without pausing a single send.

Four checkpoints, in order. Click any step or let it play.

opencart · yourstore.com
mail engineSMTP
SPF and DKIMpassing
domain reputationnot built yet
Questions

OpenCart questions, answered.

Do I need to install an OpenCart extension?
No. There is no extension, API key or integration to install. Inbox Boost works on your brand domain, and OpenCart keeps sending through the mail engine you have set.
My store uses PHP mail() on shared hosting. Does this help?
Yes, once the mail is authenticated. OpenCart’s docs recommend SMTP over PHP mail() and tell you to check SPF and DKIM and confirm your server’s IP is not blacklisted. With that in place, the reputation built here counts for the mail your store sends.
Do newsletters affect my order emails?
They share a domain, so they share its reputation. Marketing > Mail sends through the same engine as order confirmations, which is why building the domain’s reputation, and sending newsletters only to subscribers who opted in, helps both.
Why are my OpenCart emails going to spam?
OpenCart’s docs point to the usual causes: SPF and DKIM records that are missing or wrong, a blacklisted server IP, and lists with inactive or bouncing addresses. Fix authentication first, test with a small group, then build the domain’s reputation here.
Can I see whether it is working?
Yes. Inbox placement tests show where your OpenCart mail lands, Primary, Promotions or Spam, across the major mailbox providers, and blacklist monitoring keeps watching the domain afterwards.
About the OpenCart facts on this page

Checked against OpenCart's own documentation on 12 October 2026. OpenCart is a trademark of its owner; SenderSignal is not affiliated with it.

Other commerce: Shopify, Magento, WooCommerce, BigCommerce. All use cases.

OpenCart keeps sending

Warm the domain behind your OpenCart store.

Start free, add the domain, and keep every order email and newsletter going out from OpenCart while its reputation builds.

Start freeHow Inbox Boost works