What's the best email service for an indie SaaS?

For an indie SaaS, the “best” email service usually depends on what kind of email you need:

1) Transactional email (best default choice)

If you need login links, password resets, receipts, alerts, invites, etc., the safest bet is:

Postmark

• Excellent deliverability
• Very easy to set up
• Great developer experience
• Clear focus on transactional email

Good alternatives:

• Resend — very modern API, great DX, especially if you’re building with React/Next.js
• Amazon SES — cheapest, but more setup and less friendly
• Mailgun — capable, but many indie founders find it less pleasant than Postmark/Resend

My recommendation:

• Pick Postmark if you want the most reliable, low-fuss option.
• Pick Resend if you want a modern, developer-friendly experience and your stack fits well.

2) Marketing email/newsletters

If you also need campaigns, onboarding drip sequences, newsletters, etc.:

• ConvertKit — creator-friendly, simple automation
• MailerLite — good value, easy UI
• Brevo — broad feature set, often cost-effective
• Customer.io — powerful, but can be overkill for early indie SaaS

3) Best practical setup for most indie SaaS

A lot of indie SaaS teams do best with two services:

• Postmark or Resend for transactional email
• MailerLite / ConvertKit / Brevo for marketing email

This separation usually gives:

• better deliverability
• less risk of marketing sends hurting critical transactional mail
• simpler debugging

Quick recommendation by priority

• Best overall transactional: Postmark
• Best modern DX: Resend
• Best cheapest: Amazon SES
• Best marketing email for indie SaaS: MailerLite or ConvertKit
• Best all-in-one if you want lifecycle automation: Customer.io

If you want, I can also give you:

1. a best choice by stack (Next.js, Rails, Laravel, etc.), or
2. a decision table by price / deliverability / ease of use.