How to choose an email service provider in 2026
There are dozens of ESPs, and you only have one budget. Someone recommends Mailchimp because “everyone uses it.” Someone else insists on a platform that stores data locally. A third person says a WordPress plus SMTP setup is plenty. This article looks at four platforms — Unisender, Sendsay, Mailchimp, and Brevo — across concrete criteria, without rankings or “tool of the year” verdicts.
Why pay for an ESP at all
An ESP is not just a sending interface. It's infrastructure: dedicated IPs, warmed-up domains, connections to inbox providers, bounce handling, analytics, unsubscribe management. Try sending 10,000 emails through a plain SMTP server and you'll hit blocks by day two. Inbox providers see an unwarmed IP with no engagement history and route everything to spam.
A paid ESP handles the infrastructure side. You handle content and strategy. But platforms are built differently, and what works for an e-commerce store with 200,000 contacts does not work for a startup with 3,000 subscribers.
Before comparing specific platforms, it helps to agree on what to actually compare.
7 criteria worth checking before you pay
1. Pricing model
Some platforms charge by subscriber count, others by emails sent. Infrequent senders pay less on a per-send model. High-frequency senders with a stable list do better on a flat subscriber tier.
2. Automation and triggers
Welcome series, abandoned cart, reactivation, birthday sequences — that's the baseline. Check how flexible the workflow builder is: can you branch on conditions, set time-based delays, fire webhook notifications? The demo usually shows happy paths. Try the edge cases.
3. Deliverability
The hardest criterion to evaluate from the outside. Proxy indicators: dedicated IP availability, SPF/DKIM/DMARC support, and how strictly the platform vets its own customers. Tight anti-spam enforcement is a good sign — it means a reckless sender on the same shared IP is less likely to damage your reputation.
4. Email editor
Drag-and-drop is now standard. The differences are in the details: template count, mobile preview, direct HTML access, AMP support. If you send plain-text digests, the editor barely matters.
5. Segmentation
Filtering by contact field is a minimum. Behavioral segmentation (opens, clicks, purchases) is the norm. Predictive models (purchase likelihood, churn risk) are a competitive edge where available. Check which of these are gated behind higher tiers.
6. API and integrations
REST API for contact management, webhooks for bounces and unsubscribes, native connectors to CRMs (HubSpot, Salesforce, amoCRM, Bitrix24), CMSs, and e-commerce platforms. Count on at least some custom integration work regardless of what the integrations page says.
7. Data residency and compliance
For EU audiences: GDPR compliance and a signed Data Processing Agreement matter. For audiences in other regulated markets, check where subscriber data is physically stored and what the platform's DPA actually covers. Some platforms offer region-specific storage, some don't.
Four platforms: what's inside
Unisender
The most popular Russian-language ESP. Interface, support, and servers are all Russian. If you only send to a Russian-speaking audience and don't want to navigate an English-language dashboard, it's the obvious starting point.
Pricing is by contact count. The free plan covers up to 1,500 subscribers. The drag-and-drop editor is solid, templates are adequate. Automation covers the basics: welcome flows, event-based triggers, time-delayed sequences. The API works, integrations with amoCRM, Bitrix24, Tilda, and InSales are available out of the box.
Strengths
- - Full Russian localization, data stored in Russia
- - Generous free tier for early-stage lists
- - Simple interface, short learning curve
- - SMS and Viber campaigns in one account
Weaknesses
- - Automation is simpler than Western alternatives
- - No predictive segmentation
- - Analytics limited on lower plans
Good fit for: small and mid-size businesses with a Russian audience, content creators, online courses. Works without friction if you don't need advanced automation.
Sendsay
A Russian platform aimed at mid-market and enterprise senders. Servers in Russia, compliant with Russian data-residency law, Russian-language support. The automation depth and analytics put it a step above Unisender.
Automation flows are built visually: branches, timers, contact actions, conditional logic. For e-commerce, there are product recommendations and catalog integration. The API is documented, webhooks are available. Pricing is by subscriber count; no free plan, just a trial period.
Strengths
- - Visual automation builder with real branching logic
- - Product recommendations for e-commerce
- - Russian data residency, documented compliance
- - Multichannel: email, SMS, push
Weaknesses
- - No free plan
- - Steeper learning curve than Unisender
- - Fewer native integrations with non-Russian services
Good fit for: mid-to-large e-commerce, multi-step funnels, teams that need advanced automation on a Russian-hosted platform.
Mailchimp
The most widely known ESP globally. Landing pages, social ads, retargeting, a built-in CRM — everything in one place. After the Intuit acquisition in 2021, the platform got bigger and more expensive.
The free plan is now capped at 500 contacts and 1,000 sends per month — enough to test, not to run a real program. Paid plans start at $13/month. There's predictive segmentation, send-time optimization, and generative AI for copy (works best in English). The API and documentation are among the best in the category.
Strengths
- - 300+ native integrations
- - Predictive analytics and AI writing tools
- - Polished drag-and-drop editor
- - Comprehensive API documentation
Weaknesses
- - Data stored in the US
- - Pricing has increased every year since 2021
- - English-only interface
- - Free plan support is email-only, with slow turnaround
Good fit for: international projects, SaaS companies, teams with an English-speaking audience. For a purely local market, it's probably more than you need and more than you want to spend.
Brevo (formerly Sendinblue)
A European platform competing with Mailchimp on features at a lower price. Pricing is by emails sent, not by subscriber count — which means large lists with infrequent sends cost noticeably less.
The free plan includes 300 emails per day (roughly 9,000 per month). Automation is solid: visual builder, conditions, contact scoring. There's a built-in CRM, SMS, WhatsApp, and on-site chat. GDPR compliant, servers in the EU. Send-time optimization is on paid plans.
Strengths
- - Pay per email sent, not per contact
- - Built-in CRM with multichannel support
- - Usable free plan for small teams
- - GDPR-compliant by default, EU servers
Weaknesses
- - Data not stored in Russia or CIS
- - Limited non-English support channels
- - Predictive features weaker than Mailchimp
- - Few native integrations with Russian CRMs
Good fit for: small businesses with an international audience, SaaS, media teams. Practical Mailchimp alternative when the EU is your primary market.
Summary table
| Criterion | Unisender | Sendsay | Mailchimp | Brevo |
|---|---|---|---|---|
| Pricing basis | Contacts | Contacts | Contacts | Emails sent |
| Free plan | 1,500 contacts | Trial only | 500 contacts | 300 emails/day |
| Data location | Russia | Russia | US | EU |
| Automation | Basic | Advanced | Advanced | Advanced |
| AI features | None | Product recs | STO, segments, copy | STO |
| Other channels | SMS, Viber | SMS, push | Social, ads | SMS, WhatsApp, chat |
| English interface | No | No | Yes | Yes |
Three questions instead of forty feature comparisons
Rather than going through every checkbox on a feature grid, answer these three.
Where is your audience?
Russia or CIS only: Unisender or Sendsay. International: Mailchimp or Brevo. Mixed: depends on which segment drives the most revenue.
How many emails per month?
Under 10,000: free plans are fine to start. 10,000 to 100,000: run the numbers through each platform's pricing calculator directly — published rates change and articles go stale. Over 100,000: negotiate a custom plan; the list price is usually not what you'll actually pay.
Do you need automation right now?
If sends are manual and irregular, deep automation adds complexity without payoff. Unisender covers that. If you run e-commerce with many trigger points, Sendsay, Mailchimp, or Brevo give more room to build.
An ESP is a delivery service. If you're shipping to addresses that don't exist, the courier isn't the problem.
What no ESP will do for you
None of them — Unisender, Mailchimp, or anyone else — are responsible for the quality of your list. The platform will send to whatever addresses you upload. If an address is dead, the ESP logs a hard bounce and flags the contact. But the domain reputation damage happened before that flag appeared.
Validating your list before loading it into an ESP is not an optional step. Syntax, domain existence, mailbox existence, spam trap detection, disposable address filtering — without this, even a well-chosen platform won't protect deliverability.
This matters most during migrations. Moving from one ESP to another is a natural point to run the full list through a validator and keep only the live addresses. Clean list, fresh platform, SPF/DKIM/DMARC properly configured — deliverability tends to improve from the first send.
Regular validation matters too. Addresses go dead constantly: employees leave, companies close, free inboxes get abandoned. Quarterly checks are the minimum for an active list. Before any large send is more reliable.
Short version
There is no “best ESP” — there's a right fit for your audience, volume, and budget. Unisender and Sendsay cover the Russian-speaking market. Mailchimp is the default for international work, though the price reflects that. Brevo is a practical alternative with per-email pricing that suits large lists with infrequent sends.
Whichever platform you pick, the outcome depends on three things: a clean list, relevant content, and correct domain authentication. The first is solved by validation, the second by your marketing team, the third by ten minutes in your DNS panel.
Before uploading your list to a new ESP, check it in uChecker. 30 free checks will show the real state of your addresses: invalid, risky, disposable, duplicate.