In independent benchmarks run by deliverability monitoring firms like EmailToolTester, MailerLite consistently places in the top tier, frequently beating legacy giants with 94% to 96%+ primary inbox placement.
However, if you check user review forums, you will find a recurring grievance: sudden account suspensions and rejected onboarding applications. Understanding MailerLite’s anti-spam architecture is the key to unlocking its high deliverability without running into compliance roadblocks.
The compliance equation: Why strictness protects you
Every email service provider routes broadcasts through shared IP pools (unless you pay for a dedicated IP on Enterprise tiers). If a neighbor in that pool sends scraped cold emails or spam, your deliverability plummets alongside theirs.
MailerLite prevents this by enforcing some of the strictest automated filters in the industry:
- Spam complaint threshold: Must stay strictly below 0.2% (1 complaint per 500 emails sent). Crossing 0.3% triggers an automatic campaign halt.
- Hard bounce rate: Must stay below 5%. Higher rates indicate unverified or aged list imports.
- Unsubscribe rate: Should remain under 1% per broadcast.
- Minimum open rate expectation: Accounts consistently averaging under 3% open rates face automated compliance review.
Passing the onboarding approval review on day one
When you register a new MailerLite account, a human or AI reviewer checks your profile before you can send your first broadcast. Follow these five rules to pass on the first attempt:
- Use a custom business domain email (e.g. name@yourbrand.com). Free Gmail, Yahoo, or Outlook addresses are rejected for sender verification.
- Have an active, functional website. The reviewer visits your domain to ensure it contains real content, privacy policies, and a visible opt-in form.
- Clearly declare your opt-in source. Explain exactly how subscribers join (e.g., "Readers opt in via a blog popup form or downloadable PDF guide"). Never claim purchased, scraped, or directory lists.
- Avoid high-risk niche triggers. Crypto schemes, affiliate spam, multi-level marketing, and unlicensed financial advice are strictly prohibited by MailerLite Terms of Service.
The three mandatory DNS records: SPF, DKIM, and DMARC
Since major inbox providers like Google and Yahoo updated their sender requirements, domain authentication is mandatory. MailerLite provides unique TXT records in your account settings:
- SPF (Sender Policy Framework): Authorizes MailerLite’s mail servers to send messages on behalf of your domain name.
- DKIM (DomainKeys Identified Mail): Cryptographically signs your emails, verifying that the content was not altered in transit.
- DMARC (Domain-based Message Authentication): Instructs receiving servers what to do with unauthenticated mail (e.g., v=DMARC1; p=none; sp=none; rua=mailto:dmarc@yourdomain.com).
Warming up an imported list safely
If you are migrating an existing list from Mailchimp, ConvertKit, or Substack, do not blast all 10,000 subscribers on day one. A spike in old unengaged contacts can trigger a bounce rate exceeding 5%, causing an instant account pause.
Filter your existing list before exporting: segment subscribers who opened or clicked an email within the past 60 to 90 days. Import only that active group for your first two campaigns. Once MailerLite’s automated system registers clean 40%+ open rates with zero bounces, you can gradually re-engage older segments in small batches.