Best for
Best for ecommerce and B2C teams that want email and SMS driven by a customer data platform with real-time segmentation and deep store data.
- Freelancers
- Small and mid-sized
- Enterprise
Email Marketing Comparison
Klaviyo vs. Postmark
At a glance
At a glance
Best for
Best for product and engineering teams whose transactional email has to arrive, and who want promotional sending kept on separate infrastructure.
- Freelancers
- Small and mid-sized
- Enterprise
Cataleo does not name a winner. Both statements come from the vendors themselves.
Full Comparison
| Criterion | Klaviyo | Postmark |
|---|---|---|
| Starting price | Free plan for up to 250 active profiles and 500 email sends a month The free plan also carries $5 of mobile messages and $5 of Composer usage a month, with email support for the first 60 days. Paid plans scale with the number of active profiles and the message volume on top. | Free tier; Basic from $15 / month All three paid plans start at 10,000 emails per month and differ mainly by overage rate: Basic $15 at $1.80 per 1,000 extra emails, Pro $16.50 at $1.30, Platform $18 at $1.20. |
| Free trial | Free plan for up to 250 active profiles and 500 email sends per month, plus $5 of mobile messages a month | Free tier: 100 emails per month, no overages permitted, never expires |
| API | Yes, a REST API with webhooks, SDKs, warehouse syncs and more than 350 integrations | Yes, REST API and an SMTP service, with official libraries for TypeScript, Node.js, Python, Ruby, PHP, .NET and Java |
| Hosting | Cloud (SaaS) | Cloud (SaaS) |
| Made in | United States | Not stated |
| Campaign types | Yes, email campaigns with SMS and push from the same customer profiles | Transactional and broadcast email on separate Message Streams, plus inbound email processing that delivers received mail to your application |
| Automation and journeys | Yes, automation flows triggered by customer behaviour and events | No journey or automation builder. Sends are triggered by your own application over the API or SMTP, and delivery events are pushed back out through webhooks. |
| Segmentation and personalisation | Yes, real-time segmentation with predictive analytics on unified customer profiles | No stored audiences or segment builder. Recipients and their personalisation values are supplied per request, while Postmark maintains bounce state and suppression lists. |
| Templates and editor | Yes, a drag-and-drop email editor with templates | Reusable email templates with variable substitution, managed in the dashboard or over the Templates API; there is no drag-and-drop campaign designer |
| Deliverability and testing | Yes, deliverability tools with reporting and revenue attribution | Message Streams keep promotional sending on infrastructure separate from transactional mail. Message data is retained for 45 days, extendable to 365 days on Pro and Platform from $5 per month. Dedicated IPs start at $50 per month per IP and DMARC monitoring at $14 per month per domain. |
| Ecommerce and CRM data | Yes, a customer data platform with deep ecommerce data and more than 350 integrations including Shopify and WooCommerce | No built-in ecommerce or CRM data sync. Contact data stays in your own application, which supplies it with each send. |
| Integrations and API | Yes, a REST API with webhooks, SDKs and warehouse syncs | Yes, REST API with separate server and account tokens over TLS, plus an SMTP service with IP allowlisting. Endpoints cover email, batch sending, templates, bounces, inbound, message streams and suppressions. Official libraries for TypeScript, Node.js, Python, Ruby, Rails, PHP, .NET and Java, plus a WordPress plugin; community libraries add Go, Elixir, Laravel and Scala. |
| AI features | stated Yes | No |
| Deployment | Cloud (SaaS), Browser-based | Cloud (SaaS), Browser-based |
| Support | more entries Email helpdesk, Chat, Community forum | Email helpdesk |
| Onboarding | more entries Documentation and knowledge base, Live online demos and webinars, Personal consulting | Documentation and knowledge base |
| Company size | Freelancers, Small and mid-sized, Enterprise | Freelancers, Small and mid-sized, Enterprise |
| Integrations | Shopify, Magento 1.x, Magento 2.x, BigCommerce, WooCommerce, Wix, OpenCart, PrestaShop, Spree, Shift4Shop, Volusion | Not stated |
Add a tool
Adds a column to the table, from the tools in this category.
Row where the values differ The small markers point at the lower number, the longer list or the stated feature. They describe the data, they are not a verdict.
The short version
Key Differences
- Starting price Klaviyo Free plan for up to 250 active profiles and 500 email sends a month Postmark Free tier; Basic from $15 / month
- Free trial Klaviyo Free plan for up to 250 active profiles and 500 email sends per month, plus $5 of mobile messages a month Postmark Free tier: 100 emails per month, no overages permitted, never expires
- Support Klaviyo Email helpdesk, Chat, Community forum Postmark Email helpdesk
- AI features Klaviyo Yes Postmark No
- API Klaviyo Yes, a REST API with webhooks, SDKs, warehouse syncs and more than 350 integrations Postmark Yes, REST API and an SMTP service, with official libraries for TypeScript, Node.js, Python, Ruby, PHP, .NET and Java
Every line is one datapoint from the table above, picked automatically. Nothing here is written text.
The trade-offs
Strengths and Limitations
Klaviyo
Strengths
- Customer data platform with unified profiles behind email, SMS and push
- Real-time segmentation with predictive analytics
- More than 350 integrations including Shopify and WooCommerce
- Free plan for up to 250 active profiles
Limitations
- Pricing scales with the number of active profiles
- The free plan is limited to 500 email sends a month
Postmark
Strengths
- Message Streams keep promotional sending on infrastructure separate from transactional mail
- Standing free tier of 100 emails a month that never expires
- Official client libraries for eight languages plus a WordPress plugin
- Inbound email processing on the Pro and Platform plans
- Message data retention extendable from 45 days to 365 days on Pro and Platform
Limitations
- No automation, journey builder or stored audiences
- Inbound email is not included on the Free and Basic plans
- Dedicated IPs, extended retention and DMARC monitoring are priced as add-ons
- The free tier permits no overage, so sending stops at 100 emails
- All three paid plans start at the same 10,000 emails, so the choice is really about overage rate
Plans
Pricing
Klaviyo
- Free $0 / month Up to 250 active profiles, 500 email sends a month and $5 of mobile messages a month, with email support for the first 60 days.
- Email Not stated Paid email plan that scales with the number of active profiles, with higher sending allowances.
- Email and SMS Not stated Adds SMS and mobile messaging on top of the email plan, priced by active profiles and message volume.
Postmark
- Free $0 100 emails per month with no overages permitted, and 45 days of data retention. Never expires.
- Basic $15 Per month from 10,000 emails, overage $1.80 per 1,000. 45 days of data retention, no inbound email.
- Pro $16.50 Per month from 10,000 emails, overage $1.30 per 1,000. Adds inbound email and data retention customisable to 365 days.
- Platform $18 Per month from 10,000 emails, overage $1.20 per 1,000. Adds unlimited custom domains and message streams.
What users say
Review Scores · opens after launch
Klaviyo
- Ease of use
- Not rated yet
- User interface
- Not rated yet
- Onboarding
- Not rated yet
- Support and service
- Not rated yet
- Value for money
- Not rated yet
- Features
- Not rated yet
No reviews yet. Be the first to review this tool. Every review is checked for fairness before it appears, and the vendor cannot have one removed.
Postmark
- Ease of use
- Not rated yet
- User interface
- Not rated yet
- Onboarding
- Not rated yet
- Support and service
- Not rated yet
- Value for money
- Not rated yet
- Features
- Not rated yet
No reviews yet. Be the first to review this tool. Every review is checked for fairness before it appears, and the vendor cannot have one removed.
Where this comes from
Where this comes from
Klaviyo https://www.klaviyo.com · checked against the official source on 2026-09-17
Postmark https://postmarkapp.com · checked against the official source on 2026-09-09
This table lists factual criteria taken from information the vendors publish themselves. For how we put it together, see the methodology.