SendKernel vs Postmark
Postmark has the best delivery diagnostics in the category and a genuinely good idea in message streams, which keep transactional and broadcast traffic apart. It is also priced for low volume: around $15 for 10,000 messages with overage near $1.80 per thousand, so 50,000 messages costs roughly $87 where our sending plan is $18.
Competitor pricing verified September 4, 2026 from public pages. Check before switching — everyone's pricing moves.
Choose Postmark if
- Delivery forensics matter more than anything else — per-message event timelines are excellent.
- You want message streams enforcing separation between transactional and broadcast traffic.
- Your volume is genuinely small and predictable, where the price difference does not compound.
- You want a support team with a long reputation for answering deliverability questions properly.
Choose SendKernel if
- Your transactional volume is above about 10,000 a month, where Postmark's overage starts to dominate the bill.
- You need audience storage and broadcasts in the same account rather than a second tool.
- You want a free tier you can actually run something on.
- You want compliance gates in the send path rather than guidance to follow.
Side by side
| Postmark | SendKernel | |
|---|---|---|
| Entry plan | ~$15/mo for 10,000 | $18/mo for 50,000 |
| 50,000 transactional emails | ~$87 with overage | $18 |
| Overage rate | ~$1.80 per 1,000 | None — plan stops |
| Free tier | ~100 messages/month | 2,000 emails + 500 contacts |
| Marketing lists and broadcasts | Not the product | Marketing product |
| Delivery diagnostics | Best in class | Standard event log |
| Transactional / broadcast separation | Message streams | Separate products |
| DMARC required before sending | No | Yes |
Questions people actually ask
- Is Postmark worth the price?
- If deliverability diagnostics are the thing you are buying, it is a genuinely excellent product and the per-message premium buys real capability. If you simply need messages delivered at volume, the arithmetic is hard to defend: 50,000 messages runs about $87 there against $18 here, and that gap repeats every month.
- What are message streams and do you have them?
- Message streams are Postmark's mechanism for keeping transactional and broadcast traffic on separate reputations, so a campaign cannot damage receipt delivery. We achieve the same separation differently, by making sending and marketing distinct products with separate metering. The principle is the same and it is a good one.
- Can I run a newsletter on Postmark?
- Only awkwardly. Postmark is built for transactional mail and does not store audiences or provide broadcast tooling in the way a marketing platform does. Teams typically pair it with a second product for campaigns, which is the situation our two-product split is meant to remove.
Try it before you migrate anything
The free plan does not expire. Verify a domain, import a small segment, and send one campaign before you move your list.
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