Postmark
performance benchmarks
Browse Postmark's observed email API response time, error rates, and incident history over the last 90 days.
Live performance metrics
Real-world performance data from messages sent through Knock
| Message volume | Growth | Status page updates (30d) | Status page updates (90d) |
|---|---|---|---|
1M–10M | 4th of 10 ↓ | 5 | 10 |
From June 3rd to September 1st, Knock routed 1M–10M messages through Postmark. For adoption, Postmark ranks 4th of 10 providers based on new channel connections, with adoption slowing over the period. Postmark reported 10 status page updates over the last 90 days, 5 of which were in the last 30 days.
Response time
Response time measures how long Postmark takes to accept an API request from Knock, including connection overhead and any automatic retries. Lower values mean faster message hand-off.
| Median (p50) | p90 | p95 | p99 |
|---|---|---|---|
61ms | 212ms | 231ms | 558ms |
From June 3rd to September 1st, Postmark averaged a daily median response time (p50) of 61ms across all days in the range, meaning half of all requests on a typical day complete in under 61ms. The 99th percentile averaged 558ms, with a peak daily p99 of 1224ms. This is slightly higher than some providers, which may reflect additional processing Postmark performs on message acceptance.
Error rate
Error rate tracks the ratio of 5xx responses and timeouts to total requests. Knock automatically retries failed requests, so transient provider errors rarely affect end-user delivery.
| Avg. daily error rate | Highest daily rate | Peak error date | Zero-error days | Days above 0.01% |
|---|---|---|---|---|
0.00% | 0.01% | Aug 30 | 90 | 0 |
From June 3rd to September 1st, Postmark averaged a 0.00% daily error rate for 5xx responses and timeouts, with the highest single-day error rate reaching 0.01%. This is one of the lowest error rates among providers on Knock, indicating strong reliability and consistent uptime. Knock automatically retries failed requests, so transient provider errors rarely affect end-user delivery.
About these metrics: Data represents messages sent through Knock to Postmark during the specified period. Response time measures time from Knock to provider acceptance. Error rate includes only provider 5xx responses and timeouts.
Recent Postmark incidents
Recent status page incidents for Postmark
Started Aug 24, 2026 — Resolved Aug 24, 2026
We've now resolved the incident. Stats data has caught up and is now displaying in real time. This issue occurred from approximately 13:45 EDT to 16:25 EDT on August 24, 2026. Thank you for your patience.
Started Aug 18, 2026 — Resolved Aug 19, 2026
The issue is now fully resolved. We are continuing to improve our systems, observability, and monitoring to prevent future occurrences. Thank you for your patience. Starting August 18th at ~9:34am CT (~14:34 UTC), Postmark experienced delays in delivering open webhook events. New open events resumed delivery on August 19th at ~8:47am CT (~13:47 UTC), and all backlogged events completed re-delivery at ~4:52pm CT (~21:52 UTC).
Started Aug 18, 2026 — Resolved Aug 18, 2026
The maintenance is now complete. Thanks for your patience.
Started Aug 14, 2026 — Resolved Aug 15, 2026
The issue has been resolved after additional monitoring into the early morning. Thank you for your patience.
Started Aug 7, 2026 — Resolved Aug 7, 2026
The maintenance is now complete. Thanks for your patience.
Compare Postmark with other providers
About Postmark
Postmark is a transactional email service focused on fast, reliable delivery with transparent pricing.
Pros
- Excellent deliverability with separate infrastructure for transactional and bulk messages
- Publishes time-to-inbox data across major email providers for transparency
- Great documentation with official and community-supported SDKs for all major languages
- 45-day message and log retention on all plans
Cons
- No visual drag-and-drop email editor
- Less suited for high-volume marketing email
- Smaller feature set compared to all-in-one platforms
Frequently asked questions
What is Postmark?
Postmark is an email service provider commonly used for transactional email, password resets, welcome emails. Postmark is a transactional email service focused on fast, reliable delivery with transparent pricing.
How much does Postmark cost?
Free tier includes 100 emails per month. Paid plans start at $15/month for 10,000 emails with overages at $1.80/1K up to 125K, and $1.70/1K at 300K+. Postmark offers a free tier with up to 100 emails, with a hard sending limit on that plan.
How fast is Postmark?
Based on real-world data from messages sent through Knock, Postmark accepts API requests with a median response time of 61ms (p50) and 558ms at the 99th percentile.
How reliable is Postmark?
From June 3rd to September 1st, Postmark showed an error rate of 0.00% for 5xx responses and timeouts across 1M–10M messages sent through Knock. Knock automatically retries failed requests, so transient provider errors rarely affect end-user delivery.
What are the pros and cons of Postmark?
Key strengths include excellent deliverability with separate infrastructure for transactional and bulk messages and publishes time-to-inbox data across major email providers for transparency. On the other hand, no visual drag-and-drop email editor and less suited for high-volume marketing email.
Does Postmark work with Knock?
Yes. Knock has a native Postmark integration that enables you to send email notifications through Postmark as part of a cross-channel workflow. You can combine Postmark with other channels like in-app feeds, push, SMS, and Slack from a single API call.
Use Postmark with Knock
Knock enables you to integrate Postmark alongside other notification channels, manage templates, and orchestrate cross-channel workflows from a single platform.