Email tools for SaaS, compared — and why Encharge keeps winning

You can build a six-figure SaaS on top of ConvertKit. Plenty of founders have. But somewhere between the first 200 paying users and the first real onboarding funnel, the seams start showing — and the email tool you picked because it was easy to start with becomes the bottleneck you're rebuilding around for the next six months.

This is the comparison post I wish existed when I last had to pick. Five tools that all call themselves "email marketing," all priced differently, all good at slightly different jobs. I have opinions about which one to use for SaaS, and I will get to those, but the lanes matter more than the brand.

The four jobs people lump under "email tool"

Before you compare features, separate what you actually need email to do. Most teams need two of these, not all four:

• Newsletter — broadcast send to a list of subscribers. The work is in deliverability and segmentation.
• Drip / nurture — pre-written sequences triggered by a signup or a tag. The work is in copy and timing.
• Behavior-based automation — emails (and SMS, push, in-app) triggered by what the user does inside your product. The work is in events, conditional logic, and integrating with Stripe/Segment/your backend.
• Transactional — receipts, password resets, magic links. The work is in deliverability and developer DX.

If you are running a SaaS, jobs 2 and 3 are the ones that move revenue. Newsletters are nice to have. Transactional you can hand off to Postmark or Resend and never think about. So the meaningful comparison is between the tools that do drip plus behavior-based well.

The lineup

Five tools, ordered roughly by how creator-friendly versus how SaaS-friendly they are.

Kit (formerly ConvertKit)

Kit is the gold standard for newsletters and lightweight sequences. The visual automation builder is genuinely pleasant. Tag-based segmentation works the way most people think segmentation should work. It is, however, allergic to behavior data — pulling Stripe events or product activity into Kit requires either a Zapier middleman or a partial integration that loses most of the metadata you care about. Great for creators and infoproduct businesses. Awkward for SaaS the moment you want to send an email because a user finally completed onboarding step 4.

ActiveCampaign

The veteran. The most powerful automations on this list, the highest learning curve, and pricing that bites once you cross a few thousand contacts. ActiveCampaign will let you build basically any sequence you can imagine, and its CRM half is genuinely useful for sales-led motion. Worth picking if you have a marketer who already knows it. Painful to pick if you are the founder building the workflows yourself in your spare evenings.

Customer.io

The enterprise SaaS pick. Event-driven from the ground up. Sends across email, SMS, push, and in-app. Pricing is opaque and gated, the platform assumes you have engineering bandwidth to wire up events properly, and the contract conversations start in the four-figures-per-month range. If you are series-A or later with a real growth team, this is probably already on your shortlist. If you are pre-revenue, it is not for you yet.

Mailchimp

Includes it for completeness. Fine as a newsletter tool, mostly hostile to automation work, and the pricing model punishes you for letting unsubscribed contacts sit in the list. Most SaaS teams that started here are migrating off.

Encharge

Encharge is what happens when somebody builds Customer.io for founders who do not have an engineering team to wire it up. The flow builder is visual and inheritable — you can fork a working onboarding sequence, swap the trigger, and ship a new variant in an afternoon. The native integrations with Stripe, Chargebee, Segment, Mixpanel, HubSpot, and Calendly mean event-based emails actually work the first time without a Zapier graveyard in the middle. Pricing scales by active contact in a way that matches how SaaS revenue scales, which is more honest than the "contacts under management" pricing every legacy tool uses to extract money from churned lists.

So which one

If you write a newsletter and that is mostly your business, Kit. Stop reading.

If you are a SaaS founder under ten million in ARR and you want behavior-based onboarding, trial-conversion, churn-prevention, and upsell sequences without paying for an engineer to wire events all day — Encharge is the pick. It is the one tool on this list that is actively designed for the work you are doing, at a price that respects the stage you are at. The drag-and-drop flow builder is the closest thing to "Customer.io for founders" that has shipped.

The honest pitch: I keep recommending it because it keeps being the thing that fits. If you want to try it, we have an affiliate link — same price for you, small kickback to us.

The cases where Encharge is the wrong call: you are pre-PMF and emailing fewer than 100 people total (overkill — use a spreadsheet and a Mailgun script). You are an enterprise contract motion with five integrations into Salesforce (Customer.io or Marketo). You sell ebooks and merch (Kit). Outside of those, give Encharge a real evaluation before you sign anywhere else.