The best Loops alternatives depend on which emails you send: developer-first APIs for transactional mail, lifecycle tools for onboarding and nurture, all-in-one marketing platforms, and newsletter software for writers. Whichever you pick, set up SPF and DKIM on your sending domain before the first email goes out.
Three kinds of email, one sender or two?
Loops sits in the email-for-SaaS group: product and marketing email for software companies. Before you compare it with anything, split your email into three kinds, because the right alternative depends on which one matters most to you.
Transactional email is triggered by something a user does: a sign-up, a password reset, a login alert. It has to arrive fast, every time. Lifecycle email is the onboarding and nurture series that moves a trial user towards becoming a customer. Marketing and newsletter email goes to your whole list: launches, updates and content.
Some tools below cover all three. Others do one job very well. Plenty of SaaS teams run two: a developer API for transactional mail and a separate tool for everything else. That's fine, as long as both send from a domain you've authenticated.
The setup step that decides your inbox rate
The UK National Cyber Security Centre's guidance on email security and anti-spoofing says SPF lets you publish the IP addresses trusted to send for your domain, and DKIM lets you cryptographically sign email to show it's from your domain.
In plain terms, those two records tell inbox providers your emails are really yours. Every sender on this page will walk you through adding them. Do it on day one, before you import a single contact, and ask any tool you're testing how it handles them if you send from two services at once.
Ten senders at a glance
| Tool | Type | Good for |
|---|---|---|
| Brevo | All-in-one platform | Email, SMS, CRM and live chat together |
| Buttondown | Newsletter software | Founders who mainly send a newsletter |
| Customer.io | Lifecycle messaging | Journeys across email, push, SMS and in-app |
| Mailchimp | Marketing platform | Email and SMS using behaviour data |
| MailerSend | Sending service | API or SMTP sending |
| Plunk | Open-source platform | Self-hosted email and campaigns |
| Postmark | Delivery service | Transactional email on time |
| Resend | Developer API | Transactional and marketing at scale |
| SendGrid | API and campaigns | Both from one provider, via Twilio |
| Userlist | SaaS automation | Onboarding and nurture for SaaS |
Types are my grouping; descriptions are the vendors' own claims, as of Nov 2026. If you want the broader small business view, my guide to email marketing software for small businesses covers tools built for non-technical teams.
Who will own email in your team?
This is the question I'd answer before any feature list. If a developer owns email, an API-first sender is a joy: templates live in code, events fire from your app and nothing needs a login. If a marketer owns it, the same tool can feel like a locked door, because every change to a welcome email becomes a ticket for engineering.
The middle ground is a lifecycle tool. Your developer sends product events once, and from then on the marketer builds journeys in a visual editor: day one welcome, a nudge if someone hasn't finished setup, a check-in before a trial ends. Switching email tools always takes longer than people expect, so plan it with this guide to choosing between email platforms when switching.
Ten Loops alternatives, A to Z
These ten are listed in no particular order, sorted alphabetically, and each line is the vendor's own claim from its website.
Brevo
Best for: Small teams who want email and SMS marketing, automation, a CRM, live chat and transactional email in one place.
Buttondown
Best for: Writers and founders who mainly send a newsletter and want simple newsletter software.
Customer.io
Best for: Growth teams who want personalised journeys across email, push, SMS and in-app messages.
Mailchimp
Best for: Marketers who want email and SMS marketing that uses real-time behaviour data and AI.
MailerSend
Best for: Developers who want an email sending service they can use by API or SMTP.
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Plunk
Best for: Technical teams who want an open-source, self-hostable platform for transactional email, campaigns and workflows.
Postmark
Best for: Engineers who care most about transactional and marketing email reaching the inbox on time.
Resend
Best for: Developer-led startups that want an email API for transactional and marketing email at scale.
SendGrid
Best for: Companies that want an email API and marketing campaigns from one provider, now available through Twilio.
Userlist
Best for: SaaS product marketers who want email automation to onboard, engage and nurture customers and leads.
Choose in four moves
- Split your emails into transactional, lifecycle and marketing, and note which matters most.
- Decide who owns email: a developer who wants an API, or a marketer who wants a visual editor.
- Check how each shortlisted tool receives your product events, so lifecycle emails fire at the right moment.
- Send real test emails to Gmail, Outlook and Apple Mail addresses and look at where they land.
Habits that keep you out of spam
- Authenticate first: SPF and DKIM on every domain or subdomain you send from.
- Separate the streams: keep password resets apart from newsletters, so a marketing complaint never delays a login email.
- Warm up slowly: start a new domain with your most engaged users and build volume over a few weeks.
- Clean your list: remove addresses that bounce and people who haven't opened in months.
- Make leaving easy: a clear unsubscribe link is better than a spam complaint every time.
AI writing help is now built into many of these tools, which saves time on subject lines and drafts. If that matters to you, my list of AI email marketing tools looks at that side in more depth. Just remember that no AI fixes an unauthenticated domain.
My advice on leaving Loops
Start with who's going to live in the tool every day. If it's your developer, go API-first and keep it lean. If it's a marketer, choose something with a friendly editor and good automation, even if your developer has to wire up a few events first.
And don't forget the boring bit: authenticate your domain, warm it up slowly and keep your list clean. A great tool can still land in spam if the domain behind it was never set up.
Do you make email software for SaaS? Tool makers can ask to be considered for a featured place on this list.
Want your tool on this list? Featured spots and reviews here are paid partnerships. Here's how to partner with me.
Frequently asked questions
Do I need SPF and DKIM?
Yes. The UK NCSC explains that SPF publishes the IP addresses trusted for your domain and DKIM signs email to show it's from your domain.
Is there an open-source option?
Plunk describes itself as open-source and self-hostable, covering transactional email, campaigns and workflows.
Can I use two email tools at once?
Yes, many SaaS teams do. Authenticate your domain for both services and keep transactional and marketing streams apart.
