Category: Email Platforms

An ESP (email service provider) is the software company that sends your marketing and transactional email at scale, on infrastructure built to reach the inbox. It stores your subscriber list, gives you tools to design and schedule messages, handles unsubscribes and authentication, and reports on what happened after you hit send. If you plan to email more than a few hundred people at once, you need one.

What is an ESP in email marketing?

In email marketing, an ESP is a platform that lets you build a list, write campaigns and deliver them to thousands or millions of inboxes. Mailchimp, Klaviyo, MailerLite, Brevo and Kit are ESPs. So are developer-focused services like SendGrid, Postmark and Amazon SES.

When people search “what is an ESP” or “ESP email,” this is almost always what they mean. The term sits at the centre of email marketing, because every newsletter, abandoned cart reminder and password reset you receive passed through one.

The “provider” part matters. You are renting sending infrastructure: mail servers, IP addresses, bounce processing and a team that negotiates with Gmail, Yahoo and Microsoft on behalf of thousands of customers. You could build that yourself. Almost nobody should.

Other things ESP stands for

The acronym collides with a few other fields, which is why the search results look strange:

• Education Support Professionals: the term the National Education Association uses for school staff such as paraprofessionals, bus drivers and food service workers.
• English for Specific Purposes: a branch of language teaching.
• Electronic Stability Program: a car safety system.
• Extrasensory perception: the psychic kind.

If you landed here looking for any of those, this article will not help. If you came for “ESP in marketing” or “ESP marketing,” you are in the right place. Marketers almost never use ESP to mean anything except email service provider.

The 7 jobs an ESP does for you

1. Stores and manages your contacts

Your list lives in the ESP, along with each person’s sign-up date, source, consent record and any custom fields (first name, last purchase, plan type). Good list management means you can segment by behaviour, suppress people who bounced and prove consent if a regulator asks.

2. Collects new subscribers

Most ESPs give you sign-up forms, pop-ups and landing pages, plus double opt-in confirmation. That last feature is worth turning on. It keeps typos and fake addresses off your list from day one.

3. Builds the email itself

Drag-and-drop editors, templates, image hosting and HTML editing are standard. Better tools also preview how your content renders in different email clients and on mobile, which saves you from the broken layouts that kill click rates.

4. Sends at scale without getting blocked

Sending is the core job. An ESP throttles delivery so Gmail does not see 50,000 messages arrive in one second, retries soft bounces, and routes mail through IP addresses with an established reputation. It also processes feedback loops, so when someone hits “report spam” at a mailbox provider that offers one, that person stops getting your mail.

5. Automates messages

Welcome series, abandoned cart flows, birthday emails, re-engagement sequences. You build the logic once and the ESP triggers each message when a subscriber does (or fails to do) something. For ecommerce, automated flows often earn more revenue per send than one-off campaigns.

6. Keeps you compliant

The ESP adds an unsubscribe link, processes opt-outs automatically and inserts your physical mailing address, both of which CAN-SPAM requires. Under GDPR, it helps you store consent records and delete data on request. It cannot make an illegal list legal, but it removes most of the paperwork.

7. Reports on results

Delivered, bounced, opened, clicked, unsubscribed, complained, and on ecommerce platforms, revenue. Treat open rates with caution: Apple Mail Privacy Protection (launched in 2021) preloads images and inflates opens for anyone using Apple Mail. Clicks, conversions and complaint rates tell you far more.

Why you can’t just use Gmail or Outlook

Personal and workplace mailboxes are built for one-to-one conversation. They have hard daily caps, and they will lock or suspend accounts that look like they are blasting a list.

Service	Daily recipient limit	Per-message limit	Built for bulk?
Gmail (free account)	500 recipients	500	No
Google Workspace	2,000 recipients	2,000 total (500 external)	No
Outlook.com	5,000 recipients	500	No
Microsoft 365 (Exchange Online)	10,000 recipients	500	No
A typical ESP	Set by your plan, often unlimited	Whole list	Yes

Limits as published by Google and Microsoft in their help documentation; they can change, and new accounts may face lower caps.

Volume is only part of the problem. Paste 200 customer addresses into CC in email and you have just shared every address with every recipient, which is a privacy breach under GDPR. Using BCC hides the addresses, but you still have no unsubscribe handling, no bounce processing and no reporting. One bad send can also drag down the reputation of the domain your staff use for everyday mail.

The sender rules that made ESPs non-negotiable

In October 2023, Google and Yahoo announced new requirements for bulk senders, with enforcement starting in February 2024. Microsoft later introduced similar rules for Outlook.com, Hotmail and Live addresses. These rules are why “I’ll just send it myself” stopped being a realistic option.

Requirement	Gmail	Yahoo	Microsoft (Outlook.com)
Applies to	5,000+ messages/day to Gmail	Bulk senders	5,000+ messages/day
SPF and DKIM	Required	Required	Required
DMARC	At least p=none, aligned	At least p=none	At least p=none, aligned
One-click unsubscribe	Required (RFC 8058), from June 2024	Required	Functional unsubscribe expected
Honour opt-outs	Within 2 days	Within 2 days	Promptly
Spam complaint rate	Below 0.3% (aim for under 0.1%)	Below 0.3%	Not published as a number
Enforcement start	February 2024	February 2024	May 5, 2025

Any decent ESP handles one-click unsubscribe headers for you. Authentication is a shared job: the ESP gives you DNS records, and you publish them on your domain. Here is what that typically looks like.

An SPF record authorises your sending services (this example combines Google Workspace and SendGrid):

example.com.  TXT  "v=spf1 include:_spf.google.com include:sendgrid.net ~all"

DKIM is usually a CNAME pointing to a key the ESP hosts and rotates (selector and host vary by provider):

s1._domainkey.example.com.  CNAME  s1.domainkey.u1234567.wl.sendgrid.net.

A starter DMARC policy that monitors without blocking anything:

_dmarc.example.com.  TXT  "v=DMARC1; p=none; rua=mailto:[email protected]"

Once your reports show legitimate mail passing, move to p=quarantine and eventually p=reject.

These records feed directly into how e-mail spam filtering at the big mailbox providers decides whether you land in the inbox, the Promotions tab or spam.

ESP vs CRM vs CDP vs MTA

People mix these up constantly, partly because vendors keep bolting features onto each other.

Tool	What it does	Examples	Sends email?
ESP	Stores subscribers, builds and sends campaigns and automations	Mailchimp, Klaviyo, Brevo	Yes, its main job
CRM	Tracks customer relationships, sales pipeline and deals	Salesforce Sales Cloud, HubSpot CRM, Pipedrive	Usually one-to-one only, or via a connected ESP
CDP	Unifies customer data from every source into one profile	Segment, Bloomreach, Klaviyo’s CDP	No, it feeds the ESP
MTA	The server software that actually relays mail	Postfix, PowerMTA	Yes, but with no marketing tools

The lines blur. HubSpot sells marketing email inside its platform. Klaviyo now markets itself as a CDP with email and SMS on top. The question to ask is simple: which tool actually sends your mail and owns your sending reputation? That is your ESP.

Types of ESPs

Not every provider targets the same customer. Picking from the wrong category is the most common mistake I see.

Category	Best for	Examples	Typical pricing model
Small business and creator	Newsletters, simple automations	Mailchimp, MailerLite, Kit, Brevo	By contacts, free tiers common
Ecommerce	Shopify and WooCommerce stores	Klaviyo, Omnisend	By contacts, revenue reporting built in
Enterprise marketing clouds	Large brands, multiple channels	Salesforce Marketing Cloud, Braze, Bloomreach	Annual contracts, custom quotes
Transactional and API	Receipts, password resets, app notifications	Postmark, SendGrid, Mailgun, Amazon SES	By volume sent

Amazon SES shows how cheap raw sending can be: $0.10 per 1,000 emails at its standard published rate. You pay for that low price with zero templates, list management or friendly interface. Developers wire it up using APIs and webhooks, which let the ESP push bounce, open and click events back to your own application in real time.

For a closer look at the first category, our roundup of small business email platforms compares the main options side by side.

How to choose the right ESP for your business

Start from what you send, not from feature lists. A store owner needs product feeds and cart flows. A writer needs a clean editor and paid subscription support. A SaaS company needs a fast transactional API and probably a separate marketing tool.

A few things matter more than people expect:

• Pricing curves. Contact-based pricing feels cheap at 500 subscribers and can climb steeply at 50,000. Some ESPs also bill for unsubscribed contacts you keep on file.
• Data export. You should be able to download your full list, tags and engagement history at any time.
• Support. Free plans often get email support only. If a deliverability problem hits during a launch, that matters.
• Dedicated vs shared IPs. Shared IPs suit most senders under roughly 100,000 emails a month. Dedicated IPs only help if you send enough volume to build their reputation.

When to switch ESPs

Switching is a real project, so do it for a real reason. Good reasons include outgrowing the automation tools, pricing that has jumped past what the platform earns you, missing integrations your business now depends on, or persistent deliverability problems that support cannot explain.

A bad reason is a single disappointing campaign. Deliverability is mostly about your list quality and engagement, and those problems follow you to any platform.

If you do move, plan for these steps:

• Export everything, including suppression lists (unsubscribes, bounces, complaints). Importing those people into the new tool as active contacts is a fast route to complaints.
• Rebuild automations before you switch off the old ones, so nobody falls into a gap.
• Publish the new provider’s SPF and DKIM records before your first send, and remove the old ones once you have fully cut over.
• Warm up gradually. Start with your most engaged segment and increase volume step by step; a new dedicated IP typically needs four to eight weeks.
• Watch Google Postmaster Tools and your complaint rate daily for the first month.

FAQ

What are ESPs in simple terms?

ESPs are companies that send email on your behalf to large lists. They give you the tools to collect subscribers, design emails, automate sends and track results, plus the infrastructure to get those emails delivered.

Is Gmail an ESP?

No. Gmail is a mailbox provider, the service where people receive and read email. ESPs send into Gmail. Google’s own bulk sending rules are aimed at ESPs and the businesses using them.

Do I need an ESP for a small list?

If you are emailing a list of subscribers rather than individual contacts, yes. Even at 100 people, you need unsubscribe handling and consent records to stay within CAN-SPAM and GDPR, and many ESPs offer free plans for small lists.

Can I use more than one ESP?

Yes, and many businesses do. A common setup pairs a marketing ESP for newsletters and promotions with a transactional service for receipts and password resets, often on separate subdomains so one stream cannot hurt the other’s reputation.

What does an ESP cost?

It ranges from free tiers for small lists to six-figure annual contracts for enterprise platforms. Most small business tools charge monthly based on contact count, while transactional services usually charge per thousand emails sent.

The best email marketing platforms for small businesses keep the bill small while your list is small. They also get your mail into the inbox under the Gmail, Yahoo and Microsoft sender rules, and they let you send a good-looking newsletter without hiring a designer. Below are ten platforms ranked for small teams, with pricing, free-plan limits, how each one bills you, and the specific type of business each one suits.

Our top pick, in one paragraph

MailerLite is the best email marketing platform for most small businesses. Its drag-and-drop editor is the easiest to learn on this list. The automation builder handles welcome series and abandoned carts without a manual. Landing pages, signup forms and a website builder are included, and paid plans start at $12 a month. It lacks a CRM and a native SMS-first setup. Most small teams don’t need either in year one.

If you run a Shopify store and expect email to drive a big share of revenue, skip to Klaviyo. If you send a lot of email to a modest list, look at Brevo first. It bills by emails sent, not by contacts.

Quick comparison: best email marketing services for small businesses

Prices below are US list prices from each vendor’s pricing page in 2025, for the smallest paid tier on monthly billing unless noted. Vendors change these often, so treat them as a starting point and confirm before you commit.

Rank	Platform	Best for	Free plan	Paid plans from
1	MailerLite	Most small businesses	Yes, up to 250 subscribers, 12,000 emails/month	$12/month
2	Brevo	High send volume, transactional plus marketing	Yes, 300 emails/day	$9/month
3	Klaviyo	Shopify and ecommerce stores	Yes, 250 active profiles, 500 emails/month	$20/month
4	Mailchimp	Integrations and brand familiarity	Yes, 250 contacts, 500 sends/month	$13/month (Essentials)
5	Kit (formerly ConvertKit)	Creators, newsletters, digital products	Yes, up to 10,000 subscribers	About $33/month billed annually
6	Constant Contact	Local businesses, events, phone support	No (free trial)	$12/month (Lite)
7	Omnisend	Budget ecommerce, email plus SMS	Yes, 250 contacts, 500 emails/month	$16/month
8	ActiveCampaign	Advanced automation and sales follow-up	No (14-day trial)	$15/month billed annually
9	Moosend	Cheapest paid automation	No (30-day trial)	$9/month
10	HubSpot	Teams already using HubSpot CRM	Yes, 2,000 sends/month with HubSpot branding	$15/seat/month billed annually

How we ranked these email platforms for businesses

The ranking weighs the things that actually decide whether a small business sticks with a platform after the first three months. Feature count was not one of them.

• Cost at your size, and at 5x your size. A cheap starting price means little if the next contact tier doubles your bill. We looked at how each platform counts what you pay for (more on that below, because it trips up a lot of owners).
• Ease of use. Can a non-designer create a branded campaign in under an hour? Can one person run the whole thing?
• Automation that a small team will actually use. Welcome series, abandoned cart, post-purchase, re-engagement. Branching logic matters more than a list of 200 triggers.
• Deliverability tooling. Custom domain authentication (SPF, DKIM, DMARC alignment), automatic one-click unsubscribe headers, and list hygiene features. Every platform here handles the basics. Some make it much easier than others.
• Integrations. Your store, your booking tool, your forms, your CRM. Native integrations beat Zapier workarounds for anything revenue-critical.
• Support. Chat and email support on the plan you’ll actually be on, not only on the enterprise tier.

Nothing here is ranked on affiliate payout, and no platform paid for placement.

The 10 best email marketing platforms for small business

1. MailerLite: best overall for small businesses

MailerLite wins because it gets the fundamentals right at a price that stays reasonable as you grow. The drag-and-drop editor produces clean, mobile-friendly emails with very little fiddling. The automation builder is visual and covers the flows most small businesses need: welcome sequences, abandoned cart (with its Shopify and WooCommerce integrations), birthday or anniversary emails, and re-engagement.

Beyond email, you get landing pages, pop-up and embedded forms, a basic website builder, and the ability to sell digital products and paid newsletter subscriptions. For a bakery, a consultancy or a small Shopify shop, that covers the full stack.

Where it falls short: There’s no built-in CRM or sales pipeline, so B2B teams tracking deals will need a separate tool. Reporting is solid but not deep. Klaviyo’s revenue attribution is far ahead for ecommerce. MailerLite also reviews new accounts before approving them to send. That’s good for the platform’s deliverability, but it can slow your first campaign by a day or two if your signup forms or list source raise questions.

Pricing: The free plan has covered fewer subscribers over the years, so check the current cap. Paid plans start at $12 a month for 500 subscribers and scale by subscriber count. The Advanced plan adds features like a custom HTML editor, promotion pop-ups and multiple triggers per automation.

Choose it if you want one tool that handles newsletters, automations, forms and landing pages without a learning curve.

2. Brevo: best for high send volume

Brevo (it was called Sendinblue until 2023) flips the usual pricing model. You pay for the number of emails you send each month, not the number of contacts you store. If you have 8,000 contacts and email them twice a month, you’ll pay far less here than on a contact-based platform.

It also covers more channels than most tools at this price. Brevo includes transactional email (order confirmations, password resets) through the same account, plus SMS and WhatsApp campaigns, a shared inbox for live chat, and a lightweight sales CRM. A small business that wants marketing email and receipts coming from one provider will appreciate that.

Where it falls short: The editor is functional but feels busier than MailerLite’s. The free plan’s 300-emails-a-day cap means you can’t send one campaign to 1,000 people on the same day. Free and lower-tier emails also carry Brevo branding.

Pricing: Free with 300 emails per day. Starter begins at $9 a month for a monthly email volume tier, and Business at $18 a month adds features like marketing automation without Brevo’s Starter limits, A/B testing and advanced statistics.

Choose it if you have a large list that you email infrequently, or you want transactional and marketing email under one roof.

3. Klaviyo: best for ecommerce stores

If you sell online, and especially on Shopify, Klaviyo is the platform the rest are measured against. It pulls in your product catalogue, order history and browsing behaviour, then lets you segment and personalise on that data. “Customers who bought twice, spent over $100, and haven’t ordered in 60 days” takes about a minute to build.

The pre-built flows are where it pays for itself: welcome series, browse abandonment, abandoned cart, post-purchase cross-sell, win-back and back-in-stock. Each flow reports the revenue it drove. That makes it easy to see which emails earn their keep. SMS lives in the same platform, so you can coordinate both channels in one flow.

Where it falls short: Price. Klaviyo gets expensive as your profile count grows, and it’s overkill for a service business with no product catalogue. The interface has a real learning curve. Its strength is data, so if your store data is thin, you won’t get much from it.

Pricing: Free for up to 250 active profiles and 500 email sends a month. The Email plan starts at $20 a month, with SMS available as a separate plan or add-on. Klaviyo bills on active profiles, meaning contacts you can actually message. Suppressed contacts don’t count.

Choose it if you run an ecommerce store and plan to make email a major revenue channel.

4. Mailchimp: best for integrations and familiarity

Mailchimp is the name most small business owners know, and its integration library is still one of the largest in the category. Almost every booking tool, form builder, website platform and point-of-sale system connects to it. The template library is large. The editor is easy, and the AI-assisted content tools help if writing subject lines isn’t your strength.

Paid plans add customer journeys (multi-step automations), A/B testing, and on Standard and above, predictive segments and send-time optimisation.

Where it falls short: Value. Mailchimp’s free plan has shrunk to 250 contacts and 500 monthly sends (with a 250-a-day cap), and automation has been removed from the free tier entirely. Paid tiers cost more than MailerLite or Brevo for the same list size. It also counts unsubscribed and non-subscribed contacts toward your audience limit. If you don’t archive them regularly, you can pay for people you’re no longer allowed to email.

Pricing: Free for 250 contacts. Essentials from $13 a month, Standard from $20 a month, Premium from $350 a month, all scaling with contact count.

Choose it if a specific integration you depend on works best with Mailchimp, or your team already knows it well.

5. Kit: best for creators and newsletters

Kit (renamed from ConvertKit in 2024) is built around a creator’s business: a newsletter, a lead magnet, a course or digital product, maybe paid subscriptions. Its subscriber model uses tags instead of separate lists. One person can be tagged “downloaded pricing guide” and “bought course” without being counted twice.

The free Newsletter plan is unusually generous at up to 10,000 subscribers. It includes landing pages, forms, broadcasts and the ability to sell digital products. The Kit Recommendations network helps newsletters grow by cross-promoting each other.

Where it falls short: Email design is deliberately simple. That suits text-heavy newsletters but disappoints product-led brands that want image-rich layouts. Automated sequences and visual automations need a paid plan. Ecommerce features are thin compared to Klaviyo or Omnisend.

Pricing: Free up to 10,000 subscribers. The Creator plan starts around $33 a month billed annually for 1,000 subscribers (more on monthly billing). Creator Pro adds advanced reporting and subscriber scoring.

Choose it if you’re a coach, writer, course creator or podcaster whose product is expertise rather than physical goods.

6. Constant Contact: best for local businesses and events

Constant Contact has been doing this since the 1990s, and it shows in the support. Phone and chat help are available to small customers, which matters if you’re the owner, the marketer and the IT department all at once. Restaurants, gyms, churches, nonprofits and local retailers make up a big chunk of its customer base.

It also handles event registration and ticketing, social media posting and simple surveys alongside email. For a business that runs workshops or community events, that bundle removes a second subscription.

Where it falls short: No free plan. Templates feel dated next to MailerLite or Mailchimp. Automation on the Lite plan is limited, so you’ll need Standard for useful workflows.

Pricing: Lite from $12 a month, Standard from $35 a month, Premium from $80 a month, scaling by contact count. A free trial is available.

Choose it if you value a human on the phone more than the slickest interface, or events are central to how you grow.

7. Omnisend: best budget pick for ecommerce

Omnisend sits between MailerLite and Klaviyo. You get pre-built ecommerce automations (cart abandonment, browse abandonment, order follow-up) and product blocks that pull straight from Shopify, WooCommerce or BigCommerce. Email and SMS run from the same workflow builder. For most stores under a few thousand customers, it covers what Klaviyo covers at a lower monthly cost.

The editor is easy, and the product picker saves real time when you create promotional campaigns.

Where it falls short: Segmentation and reporting are good but not as deep as Klaviyo’s. Integrations outside ecommerce are limited. A service business won’t get much from it.

Pricing: Free for 250 contacts and 500 emails a month. Standard from $16 a month, Pro from $59 a month (Pro raises email limits and adds advanced reporting and more SMS credits).

Choose it if you run a small store and want ecommerce automation without paying Klaviyo prices.

8. ActiveCampaign: best for advanced automation

ActiveCampaign has the most capable automation builder among the email marketing services small businesses can realistically afford. Workflows can branch on almost anything: link clicks, site visits, purchase data, custom fields, lead scores. Higher plans include a sales CRM with deal pipelines, so a B2B service business can move a lead from “downloaded guide” to “booked call” to “proposal sent” in one system.

It has hundreds of native integrations. It also supports outbound webhooks, so developers can push automation events into almost any other system.

Where it falls short: The Starter plan is restrictive, and the features that make ActiveCampaign special (CRM, conditional content, landing pages) sit on Plus or higher. Expect a few weeks of learning before you’re comfortable. If all you send is a monthly newsletter, you’re paying for power you won’t use.

Pricing: Starter from $15 a month billed annually for 1,000 contacts. Plus and Pro tiers cost substantially more and are where most growing teams end up.

Choose it if you sell high-value services or B2B products and need email to follow up on leads automatically.

9. Moosend: cheapest paid option with real automation

Moosend, owned by Sitecore since 2021, gives you unlimited sends, an automation builder, landing pages and forms on its entry Pro plan for less than most competitors charge. The recipe library includes abandoned cart, welcome, and product recommendation flows. Setting one up takes minutes.

Where it falls short: No free plan, a smaller integration library than Mailchimp or ActiveCampaign, and less brand recognition, which means fewer tutorials and community answers when you get stuck.

Pricing: Pro from $9 a month for 500 subscribers, with a 30-day free trial.

Choose it if you want paid-tier automation on a strict budget and don’t need a long integration list.

10. HubSpot: best if you already use HubSpot CRM

HubSpot’s email tools are good. What makes them worth considering is that they sit on top of the free HubSpot CRM. If your sales team already logs calls and deals there, your emails can use that data directly, and every open and click lands on the contact’s timeline.

The free tier includes marketing email up to 2,000 sends a month with HubSpot branding. Marketing Hub Starter removes the branding and raises limits.

Where it falls short: Costs climb steeply once you need real automation, which lives on Marketing Hub Professional. Starter pricing is per seat. HubSpot bills on “marketing contacts,” so you’ll want to mark anyone you don’t email as non-marketing to keep the bill down.

Pricing: Free tools available. Marketing Hub Starter from $15 per seat per month billed annually ($20 monthly).

Choose it if HubSpot is already your CRM and you want email that talks to it without an integration.

Top small business email marketing software by use case

Your business	Start with	Runner-up	Why
Shopify or WooCommerce store, growing fast	Klaviyo	Omnisend	Purchase-based segmentation and revenue reporting
Small online store on a budget	Omnisend	MailerLite	Ecommerce flows without Klaviyo pricing
Local service business (salon, gym, clinic)	MailerLite	Constant Contact	Easy editor, forms, low cost
Restaurant, nonprofit, events-heavy	Constant Contact	Mailchimp	Event tools and phone support
Coach, writer, course creator	Kit	MailerLite	Tag-based subscribers, generous free plan
B2B services with a sales process	ActiveCampaign	HubSpot	Lead scoring and CRM pipelines
Large list, infrequent sends	Brevo	MailerLite	Billing by volume, not contacts
Absolute minimum spend on a paid tool	Moosend	Brevo	Low entry price with automation

How each platform counts what you pay for

This is the single most overlooked factor when small businesses compare email marketing platforms, and it’s why two tools with the same “from” price can cost very different amounts a year later.

Platform	What you’re billed on	Watch out for
MailerLite	Active subscribers	Unsubscribed contacts don’t count, but clean out bounces anyway
Brevo	Emails sent per month	Daily cap on the free plan; contacts stored aren’t the billing driver
Klaviyo	Active profiles	Suppress unengaged profiles to drop a tier
Mailchimp	All contacts in the audience, including unsubscribed and non-subscribed	Archive unsubscribes regularly or you pay for them
Kit	Subscribers	Free plan cap is high, so the jump to paid comes from features, not size
HubSpot	Marketing contacts (plus seats on Starter)	Set non-emailed contacts to non-marketing
ActiveCampaign	Contacts	CRM and key automation features sit on higher tiers

Here’s a concrete example. A clinic with 4,000 contacts that sends one newsletter a month sends about 4,000 emails. On Brevo, that fits comfortably into a low volume tier. On a contact-based platform, you’re priced at the 4,000-contact tier no matter how rarely you send. Flip it around: a shop with 1,500 contacts that emails three times a week sends roughly 18,000 emails a month. Contact-based pricing is usually the better deal there.

How to choose the best email marketing software for a small business

Skip the 40-row feature matrices. Answer these five questions, in order, and the list narrows itself.

1. Do you sell physical products online? If yes, start with Klaviyo or Omnisend. Ecommerce data integration is the feature you’ll lean on most, and general tools do it less well.
2. Do you have a sales process with deals and follow-ups? If yes, look at ActiveCampaign or HubSpot so email and CRM share data.
3. How big is your list and how often will you email it? Big list plus low frequency points to Brevo. Small list and frequent sends points to contact-based tools.
4. Who will build the emails? If it’s you, at 10pm, after closing, put the editor first. Use the free plan or trial to build one real campaign before you decide.
5. What do you need to connect? List your must-have integrations (store, booking system, forms, CRM) and confirm each one is native, not a third-party bridge.

Set up your platform so your email reaches the inbox

Picking a platform is half the job. The other half is configuring it so mailbox providers trust your mail. Since February 2024, Gmail and Yahoo have required bulk senders to authenticate properly, and Microsoft added its own requirements for Outlook.com consumer addresses in May 2025. Every platform on this list supports these rules. None of them can set up your DNS for you.

The current mailbox provider rules

Provider	Who it applies to	In effect from	Key requirements
Gmail	Senders of 5,000+ messages a day to personal Gmail accounts	February 1, 2024, with one-click unsubscribe required by June 1, 2024	SPF and DKIM, DMARC published (p=none is acceptable), From domain aligned with SPF or DKIM, one-click unsubscribe honored within two days, spam rate below 0.3%
Yahoo	Bulk senders to Yahoo addresses	February 2024	SPF and DKIM, DMARC published, one-click unsubscribe, low complaint rate
Microsoft (Outlook.com, Hotmail, Live)	Senders of 5,000+ messages a day to Microsoft consumer addresses	May 5, 2025	SPF, DKIM and DMARC (at least p=none) with alignment; non-compliant mail goes to Junk, with rejection as the next step

Even if you send far fewer than 5,000 messages a day, meet these rules anyway. Gmail’s baseline requirements for all senders include SPF or DKIM, valid reverse DNS and a TLS connection, and providers clearly favour authenticated mail. Most e-mail spam filtering now leans heavily on authentication results before it ever looks at your content.

The exact menu varies. In MailerLite it’s under Account settings, then Domains. In Mailchimp it’s Website, then Domains. In Klaviyo it’s Settings, then Domains, under the dedicated sending domain option. Brevo puts it under Senders, Domains and Dedicated IPs.

What the records look like

Your platform will give you the exact values. These examples show the structure so you know what you’re looking at.

SPF is a single TXT record on your root domain. You can only have one, so if you already have an SPF record for Google Workspace or Microsoft 365, add the platform’s include to it rather than creating a second record:

yourdomain.com.  TXT  "v=spf1 include:_spf.google.com include:spf.example-esp.com ~all"

DKIM is usually one or two CNAME records that point to keys your platform manages:

s1._domainkey.yourdomain.com.  CNAME  s1.domainkey.example-esp.com.
s2._domainkey.yourdomain.com.  CNAME  s2.domainkey.example-esp.com.

DMARC is a TXT record at _dmarc. Start in monitoring mode, read the reports for a few weeks, then tighten the policy:

_dmarc.yourdomain.com.  TXT  "v=DMARC1; p=none; rua=mailto:[email protected]; adkim=r; aspf=r"

Once your reports show all legitimate mail passing, move to p=quarantine and eventually p=reject. A reject policy is also a prerequisite for BIMI, which can show your logo next to your messages in supporting inboxes, though it typically requires a paid verified mark certificate.

One-click unsubscribe is handled by your platform, which adds these headers to every campaign automatically:

List-Unsubscribe: <https://example-esp.com/unsub/abc123>, <mailto:[email protected]>
List-Unsubscribe-Post: List-Unsubscribe=One-Click

Don’t remove or hide the unsubscribe link in your template to “reduce churn.” People who can’t unsubscribe hit the spam button instead, and that hurts you far more.

Troubleshooting common setup problems

• Platform says the domain isn’t verified after a day. Check that your DNS host didn’t append your domain twice (s1._domainkey.yourdomain.com.yourdomain.com). Many DNS panels add the root domain automatically, so you only enter s1._domainkey.
• DMARC fails even though SPF passes. SPF passes for the platform’s bounce domain, not yours, so it doesn’t align. Make sure DKIM is set up for your domain; aligned DKIM alone satisfies DMARC.
• Two SPF records. Merge them into one. Two records cause SPF to return a permanent error.
• Emails land in Promotions. That’s a tab, not spam. Image-heavy promotional layouts land there by design. A plainer layout and a reply-inviting tone help for relationship emails.

What to send in your first 30 days

A new platform and an empty automation tab can stall a small business for months. Build these three things first, in this order.

1. A welcome email or short series. It goes out the moment someone subscribes, when interest is highest. Deliver whatever you promised (discount code, guide, checklist), say what you’ll send and how often, and ask one simple question they can reply to. Replies are a positive engagement signal for mailbox providers.

2. One automation that maps to money. For a store, that’s abandoned cart. For a service business, it’s a follow-up sequence after an enquiry or a booking reminder. For a creator, it’s a nurture sequence leading to your paid offer. One working flow beats six half-built ones.

3. A regular campaign you can sustain. Monthly is fine. Pick a cadence you can keep for a year. A useful format for local businesses: one story or tip, one offer or update, one call to action. Send a test to yourself and one colleague every time; a typo email to your whole list is recoverable, but a broken discount code costs real sales.

Two smaller jobs are worth doing on day one too. Write a plain-text version of your signup confirmation, and make sure the reply-to address goes to an inbox someone reads. While you’re setting up your sender details, it’s a good moment to tidy up the signature you use for one-to-one customer email as well, since those messages share your domain’s reputation.

Metrics to watch (and one to stop trusting)

Stop leaning on open rate. Apple Mail Privacy Protection, introduced with iOS 15 in September 2021, preloads images for Apple Mail users, which registers as an open whether or not anyone read the email. Open rates across every platform are inflated as a result. Use them only to spot sudden drops, which can signal a deliverability problem.

Track these instead:

• Click rate. The most honest engagement signal you have. Compare campaign to campaign, not to industry averages.
• Conversion or revenue per email. Klaviyo, Omnisend and Mailchimp’s ecommerce integrations report this directly. For service businesses, track bookings or enquiries from email with UTM tags in your analytics.
• Unsubscribe rate. A spike after a specific campaign tells you that content or frequency missed.
• Spam complaint rate. Set up Google Postmaster Tools for your domain. It’s free and it shows your spam rate as Gmail sees it, which no platform dashboard can.
• Bounce rate. Hard bounces should be suppressed automatically. If they’re climbing, check how contacts are entering your list.

For testing, run A/B tests on one variable at a time (subject line, send time, or offer), and only on lists large enough to produce a meaningful difference. On a 600-person list, a subject line test won’t tell you much. Spend that effort on better content.

Switching platforms later without losing your list

Most small businesses change platforms at least once, usually when pricing jumps or they outgrow a tool’s automation. Moving is easier than vendors make it look.

• Export everything, including suppression lists. Your unsubscribed and bounced contacts must stay suppressed on the new platform. Importing them as active subscribers is a legal and deliverability problem.
• Rebuild automations before you cancel. Screenshot every flow, its timing and its copy. Nothing migrates automatically between vendors.
• Re-authenticate your domain. Add the new platform’s DKIM records before removing the old ones, so there’s no gap.
• Warm up gradually. Send your first campaigns on the new platform to your most engaged segment, then widen. A sudden full-list blast from a brand-new sending setup can trigger filtering.
• Check your forms and integrations. Every signup form, checkout opt-in and booking tool needs pointing at the new account.

Stay on the right side of the law

Every reputable platform requires you to have permission to email your contacts, and they will suspend accounts that don’t. In the US, CAN-SPAM requires an accurate From line, a non-deceptive subject, your physical postal address, and a working unsubscribe that you honor within 10 business days. In the UK and EU, GDPR and PECR generally require clear opt-in consent for marketing email to individuals. Keep a record of when and how each person signed up.

Never buy, rent or scrape email lists. Beyond the legal risk, purchased lists are full of spam traps and dead addresses, and most platforms in this guide ban them outright in their terms. Grow your list with signup forms, checkout opt-ins, lead magnets and in-store sign-ups instead. It’s slower and it works.

FAQ

What is the best email marketing platform for a small business?

MailerLite is the best fit for most small businesses because it combines an easy editor, solid automation, landing pages and forms with low monthly pricing. Online stores that want deep purchase data should choose Klaviyo instead, and creators selling digital products should look at Kit.

Which email marketing service is free for small businesses?

Several have usable free plans. Kit’s covers up to 10,000 subscribers, Brevo’s allows 300 emails a day, Mailchimp’s covers 250 contacts and 500 sends a month, HubSpot includes 2,000 sends a month, and Klaviyo and Omnisend each offer small free tiers aimed at stores. Free plans typically add the vendor’s branding and limit automation.

How much should a small business spend on email marketing software?

Most small businesses with under 2,500 contacts spend somewhere between $10 and $60 a month. Ecommerce brands using Klaviyo, and B2B teams on ActiveCampaign’s higher tiers, usually spend more because the revenue attribution and CRM features justify it. Check how each platform bills (contacts versus emails sent) before comparing prices.

Do I need my own domain to use an email marketing platform?

Yes, in practice. Gmail, Yahoo and Microsoft all expect bulk mail to be authenticated with SPF, DKIM and DMARC on the sending domain, and sending marketing email from a free @gmail.com or @yahoo.com address fails DMARC at the receiving end. A domain costs little and protects your deliverability.

Can I use Gmail or Outlook instead of an email marketing platform?

Not for marketing campaigns. Personal mailboxes have sending limits, no unsubscribe handling, no list management and no reporting, and bulk sending from them risks your account being locked. Use your regular inbox for one-to-one customer conversations and an email marketing platform for anything sent to a list.