Mailchimp and SendGrid are the two names that come up in every “which email service should we use” conversation, and in my experience most people compare them wrongly. They are not really competitors. Mailchimp is a marketing platform with an email engine bolted in; SendGrid is email infrastructure with a marketing layer bolted on. The right question is not “which is better” but “which problem am I actually trying to solve.”
The short version
If you send newsletters, promotional campaigns, and abandoned-cart flows, and you want to do it without writing code, Mailchimp is the more complete tool. If you send password resets, order confirmations, alerts, and other app-driven transactional email from your own code, SendGrid is the sturdier choice. Trying to make either one do the other’s job is where teams burn money.
Where Mailchimp wins
Mailchimp’s campaign builder is still the most pleasant one I have used. The template editor, the audience segments, the customer journey builder — it all fits together, and a marketing person can run it alone without ever pinging engineering. The reporting is genuinely good too: open tracking by device, click maps, revenue attribution if you connect a store.
The ecosystem matters as well. Practically every SaaS tool has a native Mailchimp integration, so wiring up your signup forms, your CRM, and your e-commerce platform is usually a checkbox rather than a project.
Where SendGrid wins
SendGrid is built for volume and for developers. The API is mature, the SMTP relay is reliable, and the deliverability tooling — IP warmup schedules, dedicated IPs, domain authentication, reputation monitoring — is what you need once email becomes part of your product rather than part of your marketing calendar.
The event webhook deserves a special mention. Every send, delivery, open, bounce, and spam report arrives as structured JSON that you can pipe into your own systems. That is the difference between “email seems fine” and knowing exactly what happened to every message.
The pricing trap that surprises everyone
Mailchimp bills by contact count, and its contact count includes people who unsubscribed or went cold unless you actively clean them. A list that quietly grows will quietly push you into a higher tier. SendGrid bills by volume sent, which is friendlier if you have a large list you email infrequently, and it has a free tier for low transactional volume that makes it a common first choice for side projects.
Neither model is a scam; they just reward different behavior. Model your own numbers before you commit, because switching later is painful either way.
Deliverability, honestly
Both can land in the inbox. The difference is who is responsible. On Mailchimp you accept their shared sending infrastructure and their rules, which is fine for most marketing mail. On SendGrid you are expected to manage your own reputation, especially if you move to a dedicated IP. Teams that skip the warmup process and blast from a fresh IP on day one almost always regret it.
What I would pick
Run both if you can afford the split: Mailchimp for campaigns people opted into, SendGrid for the transactional backbone of your product. If you must choose one, choose by your primary email type, not by which landing page looks nicer. And if you are a developer who finds SendGrid heavy, our Resend vs SendGrid comparison covers the newer alternatives.
Where to start
Write down your monthly volume, your list size, and how much of your email is triggered by app events versus sent by humans. That one table usually makes the decision obvious. Then read our four-way field test to see how both handled identical test sends.