The cheapest way to automate onboarding emails

"Free" email automation tools all advertise a free tier. Almost none of them advertise clearly what happens the moment you need a second automated step, a third email, or more than a few hundred contacts — which is exactly when a pre-revenue founder needs the tool most. We looked at three well-known options specifically on where the free tier actually breaks, not on the marketing page's feature list.

What "automate onboarding emails" actually requires

At minimum: a signup form, a welcome email that fires immediately, at least one follow-up email a few days later triggered by whether the first one was opened, and a way to see who's actually engaging versus who's gone quiet. That's a two-or-three-step sequence with basic conditional logic — not an advanced feature in 2026, but plenty of "free" tiers cap you at a single broadcast email with no automation at all.

Brevo

Brevo's free tier is built around a daily send cap rather than a contact-count cap, which behaves differently than most competitors: a small list that emails moderately often can stay on the free tier far longer than a growing list on a contact-capped competitor would. Multi-step automation with open-based branching is available on the free tier, not gated behind a paid plan, which is the specific feature this comparison cares about.

Systeme.io

Systeme.io's free plan bundles basic email automation with its funnel and landing-page builder, which is genuinely useful if you haven't built a signup page yet either — you get both in one login instead of stitching a page builder to a separate email tool. The trade-off is a harder contact-count ceiling on the free tier than Brevo's send-based model, so a fast-growing list will hit the wall sooner.

Mailchimp

Mailchimp's free tier is the most recognizable name of the three but the most restrictive for this specific use case — its free plan has historically limited full automation features more aggressively than Brevo or Systeme.io, pushing multi-step, condition-based sequences toward a paid tier sooner. Worth considering primarily if you're already inside the Mailchimp ecosystem for another reason, like an existing e-commerce integration.

Mailchimp explicitly prohibits affiliate marketing in its Terms of Use, so there's no program to link here — included above purely for comparison.

How we'd actually decide

• You haven't built a signup page yet and want one login for both: Systeme.io.
• You want the most automation headroom before hitting a paywall: Brevo.
• You're already committed to another tool in the same ecosystem: Mailchimp, otherwise skip it for this specific job.

Free-tier limits change often on every platform in this comparison — verify the current cap on contacts, sends, and which automation features are gated before you commit a workflow to any of these.