Mail server like mailgun or brevo

Subject: Best free email provider for auth emails in a Node.js marketplace app?

Building a marketplace app and replacing OAuth with email-based auth — magic links, OTP codes, and password resets. Looking for advice on provider choice before I commit.

My setup:

  • Node.js backend
  • Under 100 users at launch (but auth emails stack up fast per user)
  • Need a forever-free tier, not a trial
  • Using Nodemailer for sending

What I’ve narrowed it down to:

Mailtrap (4,000/mo, 150/day) seems like the best free headroom, but I’ve read mixed things about inbox placement on shared IPs. SMTP2GO (1,000/mo) has a better deliverability reputation but the lower cap worries me once I add OTP flows on top of signups.

My questions:

  1. For auth emails specifically — where speed and inbox placement matter more than anything else — does Mailtrap’s free tier hold up in production, or do magic links regularly end up in spam?
  2. Is 1,000/month on SMTP2GO actually enough for a sub-100 user app once you factor in OTP retries and password resets?
  3. Any other free-forever options I’m missing that are a better fit for transactional-only auth flows?

Not looking for a paid plan yet — strictly free until I validate the product.