Bulk email services: which kind you need, and the rules every send must meet

A bulk email service is any platform that sends one message to a large list in a single job, and for a business it comes in two kinds: email marketing software, which manages a subscribed list and its unsubscribes, and an SMTP relay or email API, which delivers mail your own systems generate. Pick by what you are sending, then by how the price is counted — per contact, per email, or per pack of credits.

The receiving side does not care which kind you choose. Gmail's published sender guidelines apply the same authentication and unsubscribe rules to every sender above 5,000 messages a day, and US law applies CAN-SPAM to business email whatever tool sent it.

The two kinds of bulk email service

Email marketing software and SMTP relays overlap, but they are built for different senders. The quickest test is who writes the message: a person composing a campaign for a list, or a system firing a message at one customer at a time.

• Email marketing software (GetResponse, Sender, EmailOctopus, AWeber, Moosend, Benchmark, Brevo): a list, signup forms, an editor, segments, automated sequences, reports and automatic unsubscribe handling. You pay for the size of the list, or in Brevo's case for the emails you send.
• SMTP relay or email API (MailerSend, and the transactional side of Brevo): your website, store or app hands messages over by API or SMTP, and the service delivers them. There is no campaign editor to speak of; you pay per email.

If you are announcing a sale to 8,000 customers who signed up for offers, that is marketing software. If you are sending 8,000 order confirmations a month, that is a relay. Many businesses run both, and our comparison of an ESP versus an SMTP relay goes through where the line falls.

How bulk sending is priced

Bulk email is priced in three ways, and the cheapest one depends on how often you send, not only on how many people you send to. Before comparing brands, estimate your monthly email volume: list size multiplied by sends per month.

Per contact or subscriber. Most marketing platforms charge by list size and cap sending as a multiple of it — AWeber Lite at 10× the subscriber count each month, Sender Standard at 12×, Benchmark Pro at 10× the contact limit. GetResponse is the exception: its plans list "Unlimited monthly email sends" at every list size, from $19 a month at 1,000 contacts on monthly billing.

Per email sent. Brevo sizes its marketing plans by emails per month — Starter is listed at $9 a month from 5,000 emails — and MailerSend prices its relay the same way: Starter is $35 a month on monthly billing for 50,000 emails, with extra usage at $1.30 per 1,000.

Credits. Moosend sells pay-as-you-go credits for seasonal senders, from $350 for 350,000 emails, as an alternative to its monthly Pro plan.

"Unlimited" bulk email, read carefully

An unlimited-sends plan removes the platform's cap, not the receiving side's rules. GetResponse's plans list unlimited monthly sends, but every message still has to pass Gmail's authentication checks and stay under its published spam-rate threshold.

What "unlimited" does change is the arithmetic. On a list-priced plan with a 10× cap, a business that emails its list three times a week will not hit the ceiling; one that sends daily might. On an unlimited-sends plan, the list size alone sets the price. There is no plan anywhere that makes an unwanted email welcome, and a service advertising "unlimited" sending to lists you bought is describing a way to be blocked.

Gmail's rules for bulk senders

Google's sender guidelines, in force since February 2024, set two levels of rules. Every sender to Gmail accounts must meet the first; senders of more than 5,000 messages a day to Gmail accounts must meet both.

• All senders: SPF or DKIM authentication on the sending domain, valid forward and reverse DNS, a TLS connection, standard message formatting, and a spam rate reported in Postmaster Tools below 0.3%.
• Above 5,000 a day: SPF and DKIM, a DMARC record for the sending domain with alignment, and one-click unsubscribe on marketing and subscribed messages.

Google's own advice is to keep the spam rate below 0.1% and never reach 0.3%. Google Postmaster Tools is free and shows your domain's rate; it pays us nothing and we recommend it to every bulk sender. We have read only Google's rules at the source for this page; other mailbox providers publish their own, so check each before a large send.

Setting up bulk sending, step by step

Set these up before the first campaign, in this order; each depends on the one before. Your email platform's help centre will give the exact DNS values for its service.

1. Send from a domain you own, never a free webmail address. Mailbox providers check the domain in the From line against the domain that signed the message.
2. Add the SPF record your platform gives you, so receiving servers can see which services may send for your domain.
3. Turn on DKIM signing for your domain in the platform and publish its key in DNS.
4. Publish a DMARC record for the domain. Start with a monitoring policy, read the reports, then tighten it once legitimate mail passes.
5. Check that one-click unsubscribe is switched on for marketing mail and that the footer shows your postal address.
6. Import only people who asked to hear from you, and remove addresses that bounce.
7. Watch your spam rate in Postmaster Tools after every large send, and pause when it rises.

The law on business email

In the United States, CAN-SPAM applies to commercial email including business-to-business mail; the FTC's guidance says plainly that the law makes no exception for it. Its core requirements are honest header and subject lines, identifying the message as an ad, a valid physical postal address, a clear opt-out, honouring opt-outs within 10 business days, and responsibility for anyone sending on your behalf.

The FTC puts the penalty at up to $53,088 for each email in violation. Consent rules in other countries differ and are often stricter; if you email people outside the US, read your regulator's guidance or ask a lawyer. This page is general information, not legal advice.

Which bulk email service to choose

Start from the job, not the brand. For campaigns to a subscribed list, compare email marketing platforms on price at your list size — our ranking of the best email marketing software prices seven of them at 5,000, 25,000 and 100,000 contacts. For system-generated mail, choose a relay priced per email.

• Large list, occasional campaigns: price Brevo first, since it charges by emails sent. Brevo runs no programme open to us — a plain link, and it pays us nothing.
• Regular campaigns, a team, no send cap: GetResponse, whose plans list unlimited monthly sends.
• Seasonal bursts: Moosend credits, from $350 for 350,000 emails.
• Receipts, alerts and app mail: MailerSend, free for 500 emails a month and $35 a month for 50,000 on monthly billing.

Links marked as partner links above may earn us a commission if you buy; the choice of tool never depends on it, and the free Google Postmaster Tools pays nothing at all.