Transactional email vs marketing email: the differences, and how to send each

The US and the UK draw the line in different places. In the US, the Federal Trade Commission (FTC) lists five kinds of transactional or relationship message under the CAN-SPAM Act. In the UK, the Information Commissioner’s Office (ICO) says a service message with any promotion in it counts as direct marketing, even when promotion is not its main purpose. The UK and EU columns below follow the ICO; EU regulators differ on details, so treat them as the cautious answer.

CAN-SPAM classifies a message by its primary purpose. The FTC’s compliance guide gives two checks for a message that mixes a transaction with promotion. It is commercial if a recipient reading the subject line would reasonably conclude it advertises something. It is also commercial if the transactional part does not appear mostly at the beginning.

So a receipt with the order details first, a plain subject such as “Your receipt for order 1042”, and a small offer at the bottom generally stays transactional. Legal is not the same as wise: Google’s sender guidelines ask you not to mix different types of content in one message, so a receipt is safest without the offer. Change the subject to “Your receipt, plus 20% off” or lead with the offer, and it becomes commercial. An appointment reminder with a “Book again” button at the end works the same way. A commercial message must have honest headers and subject line, say it is an advertisement unless the recipient opted in, show your postal address (a registered PO box counts), offer a way to opt out, and honour an opt-out within 10 business days. The marketing email guide has the full rules.

Mailbox providers such as Gmail judge mail by the domain it comes from and by how recipients react, so complaints about a campaign count against the domain it was sent from. Google’s sender guidelines ask for the same From address per category of message, no mixing of content types in one message, and a separate IP address per message type if you send from more than one. On a shared service the IP addresses (the servers’ network addresses) are the provider’s job; at Rasket a dedicated IP is an add-on from the Scale plan up.

The usual way to follow that is a subdomain: a name under your own domain, such as news.yourshop.com under yourshop.com. It costs nothing: you create it by adding a few lines, called records, to your domain’s DNS settings, the address book that tells the internet where your domain’s mail and website live. They are wherever you bought the domain. Send product mail from send.yourshop.com and campaigns from news.yourshop.com, each set up as its own sending domain. In Rasket, go to Domains, click Add domain, type the subdomain, and copy the records it shows into your DNS settings. It shows the steps for the company that runs your DNS, and connects in one click for Cloudflare and the domain sellers that support it; email domain verification, step by step walks through it.

A small sender can start simpler. A few hundred campaign emails a month can go from news@yourshop.com while receipts go from orders@yourshop.com; move campaigns to a subdomain when they reach thousands. Gmail’s bulk-sender rules start when you send close to 5,000 messages or more to personal Gmail accounts in 24 hours, counted across your whole domain, and once you cross that line you stay a bulk sender. The Gmail and Yahoo requirements list what that adds.

A subdomain separates; it does not isolate. Gmail counts every subdomain toward the parent domain, and providers also weigh the parent’s reputation. The subdomain guide says what it does and does not protect.

One API call per message, sent the moment the event happens. Two habits matter. Attach a label made from the event, such as the order number (an idempotency key), so if your app sends the request again after a network hiccup, the customer still gets one receipt; idempotent email sends and email API rate limits cover retries. And keep the id Rasket returns with the order: when a customer says the receipt never arrived, its events show whether it was delivered, bounced or suppressed.

// Throws on any error. Retry a 429 whose code is rate_limit_exceeded, or a 5xx, with the
// same key; a quota 429 (daily or monthly allowance) does not clear by retrying.
async function rasket(path: string, body: unknown, idempotencyKey?: string): Promise<any> {
  const response = await fetch(`https://api.rasket.com${path}`, {
    method: "POST",
    headers: {
      authorization: `Bearer ${process.env.RASKET_API_KEY}`,
      "user-agent": "yourshop/1.0",
      "content-type": "application/json",
      ...(idempotencyKey ? { "idempotency-key": idempotencyKey } : {}),
    },
    body: JSON.stringify(body),
  });
  if (!response.ok) throw new Error(`${path}: ${response.status} ${await response.text()}`);
  return response.json();
}

// The key is the order, so a retry cannot send a second receipt.
const receipt = await rasket(
  "/emails",
  {
    from: "Your Shop <orders@send.yourshop.com>",
    to: ["ronald.williams@example.com"],
    subject: "Your receipt for order 1042",
    html: "<p>Thanks for your order. Total: $42.00.</p>",
    text: "Thanks for your order. Total: $42.00.",
  },
  "receipt-order-1042",
);
console.log(receipt.id); // store it against the order

A receipt carries no unsubscribe header, and Rasket adds none to API sends. Google requires one-click unsubscribe only on marketing and promotional mail.

A campaign is built from four things: a topic (what people subscribe to, such as “Product updates”), contacts (people, with their choice per topic), a segment (a saved filter over contacts) and the broadcast (the message, sent to a segment under a topic). Only contacts opted in to the topic receive it. You can do all of it without code: topics, contacts and segments are under Audience in the dashboard, and the broadcast under Campaigns. Rasket refuses to send until the From domain is verified and your postal address is set, because the address goes in the footer.

“An opt-in you can evidence” means a record of what the person agreed to: the wording of the checkbox, the date and the form they used. Leave the box unticked; a pre-ticked box is not consent in the EU or the UK. Rasket keeps each contact’s consent history: what changed, for which topic, where the change came from and when.

// default_subscription is what a contact who never chose gets: "opt_out" keeps
// them off this list until they opt in.
const topic = await rasket("/topics", {
  name: "Product updates",
  description: "What shipped, once a month.",
  default_subscription: "opt_out",
});

// The consent you collected, recorded on the topic.
await rasket("/contacts", {
  email: "ronald.williams@example.com",
  first_name: "Ronald",
  topics: [{ id: topic.id, subscription: "opt_in" }],
});

const segment = await rasket("/segments", {
  name: "Product updates, opted in",
  filter: { all: [{ topic: topic.id, subscription: "opt_in" }] },
});

const campaign = await rasket("/broadcasts", {
  name: "October product update",
  segment_id: segment.id,
  topic_id: topic.id,
  from: "Your Shop <hello@news.yourshop.com>",
  subject: "What shipped in October",
  html: '<p>Hi {{{FIRST_NAME|there}}}, three things shipped.</p><p><a href="{{{UNSUBSCRIBE_URL}}}">Unsubscribe</a></p>',
});

// Refused with a 422 until the From domain is verified and the team has a postal address.
await rasket(`/broadcasts/${campaign.id}/send`, {}, "october-update-send");

List-Unsubscribe: <https://www.rasket.com/u/v1.1.eyJ0…>
List-Unsubscribe-Post: List-Unsubscribe=One-Click

If your store or booking platform already sends receipts, reminders and shipping notices, keep it doing so: it knows the order. Check that they come from your own domain. On Shopify, go to Settings → Notifications and click Email domain authentication under Sender email; if the domain is not authenticated, Shopify rewrites the sender to a shopifyemail.com address. On any platform, send yourself a test, open it in Gmail, click More (the three dots next to Reply) and choose Show original. The DKIM line should name your domain; DKIM is a signature that shows which domain vouches for the message.

Abandoned cart reminders are marketing: send them with an unsubscribe, never to someone who unsubscribed, and in the EU and UK only to people who agreed to marketing or fall under the soft opt-in. In Rasket that is an automation triggered by your cart event, and automation sends get the unsubscribe header and footer added. Order confirmation and abandoned cart emails covers both.

A SaaS product sends most of its mail from code. Invoices, failed payments, trial-ending and usage-limit notices go through the email API from the event that caused them. Send an onboarding sequence as a marketing automation if it nudges toward an upgrade or reaches people in the UK or EU: the sign-up starts it, and its unsubscribe stops the tips without stopping invoices.

• Use the email API (or your shop platform) for anything caused by one person’s action, with an idempotency key from the event that caused it.
• Use campaigns or automations for anything you send to a group or as a sequence.
• Give each subdomain its own API key when you split them: a sending key limited to send.yourshop.com for product mail, and a full-access key for campaigns, because creating contacts and campaigns needs more than a sending key allows. Keep the full-access key on your server only, since it can also read your contacts. Either can be revoked without stopping the other stream.

Both kinds count toward one monthly email allowance, and each plan includes a number of contacts. Free covers 3,000 emails a month of any kind, at most 100 a day with campaigns included, and 900 contacts. A startup sending 20,000 transactional and 10,000 campaign emails a month to 3,000 contacts pays $20 a month: Pro’s tier for up to 50,000 emails, with 4,500 contacts included. The price rises with volume. At 100,000 emails and 10,000 contacts it is $70.20: $35 for Pro’s 100,000-email tier, which includes 6,750 contacts, and $35.20 for the contacts past them. The pricing page has the calculator.

If your marketing team works entirely in a visual campaign tool and nobody on your side writes code, a dedicated email marketing platform will suit them better; keep the transactional side wherever your developers are. Two tools work too; the cost is two bills, two sets of DNS records, and unsubscribes and bounces kept in two places that have to agree. The email API page and the campaigns page show what each side includes.