Customer.io vs Postmark
Pricing
Customer.io: From $100/mo
Postmark: Free for 100 emails/mo, from $15/mo
Description
Customer.io: Behavior-based email and push for SaaS
Postmark: Transactional email service built around one promise: your emails hit the inbox
Pros
- Powerful segmentation
- Multi-channel (email, SMS, push)
- Great for product-led growth
- Industry-leading deliverability: 99%+ inbox placement
- Emails typically arrive in under 10 seconds
- Detailed delivery analytics and debugging tools
Cons
- Expensive for small lists
- Steep learning curve
- More expensive per email than Resend or SendGrid
- Transactional email only: no marketing campaigns, newsletters, or bulk sends
- 100 email free tier is barely enough to test with
Details
Customer.io sends messages based on what users actually do in your product. Founded by Colin Nederkoorn, “fundstrapped” (took some money but runs like bootstrapped). Took 18 months to hit $10k MRR, now at $100M ARR. Great for SaaS doing product-led growth.
Postmark has been laser-focused on one thing for over a decade: making sure transactional emails hit inboxes, not spam folders. Password resets, order confirmations, shipping notifications: the emails your users actually need to receive. They keep their deliverability high by refusing to send marketing email on the same infrastructure.
You pay more per email than alternatives, but for transactional messages where delivery matters (think: password resets, payment receipts), that premium buys real reliability. If your app sends emails that users rely on, Postmark is the safest bet.
Verified
