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) |
|---|---|---|---|
25M–100M | 4th of 10 → | 5 | 11 |
From January 1st to March 31st, Knock routed 25M–100M messages through Postmark. For adoption, Postmark ranks 4th of 10 providers based on new channel connections, with adoption holding steady over the period. Postmark reported 11 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 |
|---|---|---|---|
31ms | 93ms | 120ms | 242ms |
From January 1st to March 31st, Postmark averaged a daily median response time (p50) of 31ms across all days in the range, meaning half of all requests on a typical day complete in under 31ms. The 99th percentile averaged 242ms, with a peak daily p99 of 38235ms. This places Postmark among the fastest providers on the Knock platform for API response times.
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% |
|---|---|---|---|---|
0.03% | 2.37% | Mar 27 | 83 | 4 |
From January 1st to March 31st, Postmark averaged a 0.03% daily error rate for 5xx responses and timeouts, with the highest single-day error rate reaching 2.37%. 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 Mar 27, 2026 — Resolved Mar 28, 2026
We've resolved the incident. Thanks for your patience.
Started Mar 26, 2026 — Resolved Mar 26, 2026
The issue has been resolved.
Started Mar 25, 2026 — Resolved Mar 25, 2026
The issue has been resolved! Thank you for patience.
Started Mar 8, 2026 — Resolved Mar 8, 2026
Resolved! Thank you for your patience.
Started Mar 4, 2026 — Resolved Mar 4, 2026
We've now resolved the incident. 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 31ms (p50) and 242ms at the 99th percentile.
How reliable is Postmark?
From January 1st to March 31st, Postmark showed an error rate of 0.03% for 5xx responses and timeouts across 25M–100M 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.