KoltrixThe Minimal Email Stack for a Pre-Seed SaaS
Before product-market fit, your email setup should be small, cheap and reliable. The four pieces a pre-seed SaaS needs, and what to put off until later.
On this page(9 sections)
Pre-seed founders are good at over-buying software. A campaign platform, a CRM with sequences, a help desk with three tiers of automation, an analytics add-on, all configured before the product has twenty users. Email is one of the easiest places to overbuild, and one of the most expensive places to get the basics wrong.
Here's the smallest email setup that does the job properly, and what can safely wait.
The four things you actually need
Strip email down to its jobs and a pre-seed SaaS has four:
- Mailboxes on your own domain for the founders, plus a couple of shared addresses.
- A way for your app to send email: verification, password resets, receipts, a welcome email.
- Somewhere replies land that a human reads.
- Deliverability basics: SPF, DKIM, DMARC and automatic bounce and complaint handling.
That's it. If those four work, you can run a real business.
1. Mailboxes on your domain
You need [email protected], not a Gmail address, from the first customer conversation. It affects whether people trust your emails, whether they land in spam, and whether you can hand the address over later.
Add a few shared addresses from day one:
hello@orsupport@for customersbilling@for anything payment-relatedsecurity@so researchers have somewhere to report issues
At this stage these can be aliases that land in the founders' inboxes, or better, shared mailboxes both founders can see. The important thing is that they belong to the company, not to a person.
2. App sending
Your product will send email from the first signup. You need:
- An API or SMTP relay your app can call
- Domain authentication so mail is signed as your domain
- Delivery events, at minimum bounces and complaints, so you stop sending to bad addresses
- A way to look up whether a specific email was delivered, for "I didn't get my reset link" moments
Don't send app email from a founder's mailbox through SMTP. It works until a sudden burst of signups trips the mailbox provider's sending limits, and your password resets stop.
3. Replies
This is the piece most early stacks skip. Your app's emails go out from noreply@, and customers who reply to a receipt or a welcome email hit a dead end. At the pre-seed stage, those replies are some of the most valuable feedback you'll get.
Set a reply-to address on every app email that reaches a monitored inbox, and test it by replying to your own emails.
4. Deliverability basics
You don't need a deliverability consultant. You need:
- SPF listing every service that sends as your domain
- DKIM signing for both your mailboxes and your app sending
- DMARC starting at
p=nonewith reports going to an address someone glances at, then tightening once you know everything is aligned - Automatic suppression of hard bounces and complaints
You can check your records with a free tool like our DMARC checker.
Three ways to assemble it
There's no single right answer. Here are three common shapes, each with honest trade-offs.
| Setup | How it works | Good for | Watch out for |
|---|---|---|---|
| Office suite + transactional API | Google Workspace or Microsoft 365 for mailboxes; a separate API for app email | Teams that also want docs, calendar, video | Two vendors, two DNS setups; replies to app mail need routing |
| Budget mailbox host + transactional API | Zoho Mail, Fastmail or similar for mailboxes; a separate API | Keeping cost down | Same split as above; check shared-address features |
| Combined inbox + API | One tool for mailboxes, shared addresses and app sending, e.g. Koltrix | Teams who want one bill and replies to app mail in the team inbox | Fewer features than an office suite; check client and certification needs |
If you choose the combined route with Koltrix, know the limits up front: it's a web app with no IMAP access or desktop client support in its first release, it has no office suite, and it has no SOC 2 or ISO certification. For many pre-seed teams none of that matters yet; for some it's a dealbreaker. The custom-domain email guide for indie SaaS covers the setup steps.
What to put off
These are all real tools for real problems. They're just not pre-seed problems.
- A campaign and automation platform. Until you have a few hundred users and a clear onboarding path, a handful of emails sent from your app is enough. Write the welcome email and the trial reminder in code.
- A full help desk. With a few support emails a day, a shared mailbox is faster and cheaper. You'll know you've outgrown it when you need SLAs, routing rules and reporting.
- CRM sales sequences. Founder-led sales at this stage means personal emails, written by you, followed up by you.
- Dedicated sending IPs. At low volume a dedicated IP can hurt rather than help, because it has no reputation history.
- A newsletter tool. If you have something to announce, a plain email to your users from your app or your mailbox is fine.
A one-afternoon setup plan
- Register or confirm your domain and lock down the registrar account with 2FA.
- Choose your mailbox provider and create founder mailboxes plus shared addresses.
- Publish SPF, DKIM and DMARC for the mailbox provider.
- Set up app sending, authenticate the domain for it, and add it to SPF.
- Point every app email's reply-to at
support@orhello@. - Send test emails to Gmail, Outlook and Yahoo accounts and check they land in the inbox.
- Trigger a password reset and reply to it. Confirm the reply arrives.
- Set a monthly reminder to check DMARC reports and bounces.
Key takeaways
- A pre-seed SaaS needs four things: domain mailboxes, app sending, a home for replies, and authentication.
- Shared addresses should belong to the company from day one.
- Don't send app email through a founder's mailbox.
- Choose any of several setups; be honest about each one's trade-offs.
- Put off campaign tools, help desks and dedicated IPs until you have the problems they solve.
Start with Koltrix
Your domain, one inbox, and an API that sends.
A team inbox where AI sorts and drafts (nothing is sent without your click), plus the transactional API and SMTP relay your product sends with. 7 days free, no card.
