Deliverability
Updated
Transactional email
Definition
Transactional email is a one-to-one message triggered by a user's action or account event, such as a password reset, login code, receipt or shipping notice. Its purpose is to complete or confirm something the recipient started.
How it works
Your application calls an email API or SMTP relay when an event happens. The message goes to one recipient, usually immediately, and often contains time-sensitive content like a one-time code.
Marketing email (campaigns, newsletters, promotional sequences) is sent to many people at once to promote something. Mailbox providers and laws treat the two differently.
Under the US CAN-SPAM Act, messages whose primary purpose is transactional or relationship content are exempt from most marketing requirements, but they still must not contain false or misleading header information. Adding promotional content can change how a message is classified.
Example
Any SMTP-capable tool can send transactional mail through Lumail.
Why it matters
Transactional emails are the ones people actively wait for. A login code that arrives five minutes late is a failed login.
They usually have the highest engagement of anything you send. Keeping them on the same domain as your marketing mail strengthens that domain's reputation, as long as marketing sends cannot delay them.
Best practices
- Keep transactional emails free of promotions so they stay clearly transactional.
- Send them on a priority path so a large campaign never delays a password reset.
- Authenticate with SPF, DKIM and DMARC exactly like marketing mail.
- Do not add a marketing unsubscribe to messages people need, such as receipts and security alerts.
How Lumail handles transactional email
Lumail sends transactional email through its REST API, TypeScript SDK and an SMTP relay at smtp.lumail.io:587 with STARTTLS, from the same verified domain as your newsletter.
Transactional sends travel on a separate instant lane, so a large campaign cannot make a login code wait. They do not carry marketing unsubscribe headers, and per-recipient rate guards (5 sends per 10 minutes, 20 per 24 hours) protect each inbox.
Check a real message with the free mail tester or the spam tester.
Frequently asked questions
Is a welcome email transactional or marketing?
It depends on the content. An account confirmation is transactional. A welcome sequence that promotes products is marketing and should respect unsubscribes.
Do transactional emails need an unsubscribe link?
Under CAN-SPAM, messages whose primary purpose is transactional do not. The Gmail and Yahoo one-click unsubscribe requirement applies to marketing and subscribed messages.
Should transactional and marketing email use different domains?
Many teams use a subdomain per stream to isolate reputation. Lumail keeps both on your domain but separates them in the sending pipeline so marketing volume never delays transactional mail.
Related terms, tools and docs
- DeliverabilityEmail deliverabilityEmail deliverability is the ability of your emails to reach recipients' inboxes rather than bouncing or landing in spam.
- List managementOne-click unsubscribeOne-click unsubscribe is a standard (RFC 8058) that lets mail clients unsubscribe a recipient with a single HTTPS POST, without opening a web page.
- DeliverabilitySender reputationSender reputation is the trust score mailbox providers assign to your sending domain and IP addresses, based on how recipients and their systems react to your mail.
- AuthenticationDKIMDKIM (DomainKeys Identified Mail) is a cryptographic signature added to each email's headers.
- Free toolFree mail testerSend a real email and get an SPF, DKIM, DMARC and content report.
- Free toolFree spam testerCheck an email for the patterns that push mail to spam.
- DocsTransactional email over SMTPSend from SMTP-only tools through Lumail.
- DocsSend email APISend a transactional email with one request.
- DocsRecipient rate guardsPer-address caps and bounce cooldowns.
Browse every definition in the email marketing glossary.
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