Mailgun vs Postmark
Compare Mailgun and Postmark based on observed API performance, features, and pricing
Live performance comparison
Real-world performance data from messages sent through Knock
| Provider | Message volume | Growth | Status page updates (30d) | Status page updates (90d) |
|---|---|---|---|---|
| 100M–500M | 5th of 10 → | 5 | 11 |
| 25M–100M | 4th of 10 ↓ | 1 | 7 |
From April 13th to July 12th, Knock routed 100M–500M messages through Mailgun and 25M–100M through Postmark. Mailgun reported 11 status page updates over the last 90 days, while Postmark reported 7.
Response time
Response time measures how long each provider takes to accept an API request from Knock, including connection overhead and any automatic retries. Lower values mean faster message hand-off.
The chart above shows each provider's daily median response time (p50) from April 13th to July 12th. The top-line number is an average of these daily values: Mailgun averaged 136ms compared to 4ms for Postmark. Mailgun's highest daily p50 was 167ms; Postmark's was 60ms. Postmark is 132ms faster at the median, which can add up at high volumes.
The 90th percentile (p90) captures the slowest 10% of requests, revealing how each provider handles moderate stress. Averaged across all days, Mailgun has a p90 of 199ms compared to 74ms for Postmark. The highest daily p90 was 8262ms for Mailgun and 220ms for Postmark. Postmark handles these slower requests 125ms faster, suggesting more consistent performance across the board.
The 99th percentile (p99) represents the long tail — the slowest 1% of requests. Averaged across all days, Mailgun reached 592ms at p99 while Postmark reached 234ms. The highest daily p99 was 15385ms for Mailgun and 1429ms for Postmark, indicating the worst-case response time during spikes or provider-side congestion. Postmark shows a tighter tail, which may matter for time-sensitive notifications like one-time passwords or real-time alerts where even rare delays can impact user experience.
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.
| Provider | Avg. daily error rate | Highest daily rate | Peak error date | Zero-error days | Days above 0.01% |
|---|---|---|---|---|---|
| 0.00% | 0.04% | Jun 23 | 90 | 1 |
| 0.00% | 0.04% | Jul 9 | 85 | 3 |
Averaged across the date range, Mailgun shows a 0.00% daily error rate compared to 0.00% for Postmark. The highest single-day error rate was 0.04% for Mailgun and 0.04% for Postmark. Both providers show similar reliability levels, with error rates well within acceptable thresholds. Knock automatically retries failed requests to both providers, minimizing the impact of transient errors on end-user delivery.
About these metrics: Data represents messages sent through Knock during the specified period. Response time measures time from Knock to provider acceptance. Error rate includes only provider 5xx responses and timeouts.
Recent Mailgun incidents
Recent status page incidents for Mailgun
Started Jul 10, 2026 — Resolved Jul 10, 2026
Jul 10, 13:11 PDT Resolved - This incident has been resolved. Jul 10, 12:58 PDT Monitoring - A fix has been implemented and we are monitoring the results. Jul 10, 12:48 PDT Update - A fix is in the process of being rolled out to impacted regions. Jul 10, 12:33 PDT Update - We are continuing to work on a fix for this issue. Jul 10, 11:59 PDT Update - We are continuing to work on a fix for this issue. Jul 10, 11:36 PDT Update - We are continuing to work on a fix for this issue. J
Started Jun 25, 2026 — Resolved Jun 25, 2026
Jun 25, 13:35 PDT Resolved - This incident has been resolved. Jun 25, 13:24 PDT Monitoring - A fix has been implemented and we are monitoring the results. Jun 25, 13:21 PDT Identified - The issue has been identified and a fix is being implemented. Jun 25, 13:03 PDT Update - We are continuing to investigate this issue. Jun 25, 12:21 PDT Investigating - We are currently investigating an issue with email previews not working. Outbound processing, inbound processing, logs and webhook de
Started Jun 23, 2026 — Resolved Jun 23, 2026
Jun 23, 09:09 PDT Resolved - This incident has been resolved. Jun 23, 08:56 PDT Monitoring - A fix has been implemented and we are monitoring the results. Jun 23, 08:25 PDT Update - We are continuing to work on a fix for this issue. Some customers may see log delays. Outbound processing, inbound processing, and webhook delivery continue operating normally. Jun 23, 07:52 PDT Update - We are continuing to work on a fix for this issue. Some customers may see log delays. Outbound processin
Started Jun 18, 2026 — Resolved Jun 18, 2026
Jun 18, 03:24 PDT Resolved - This incident has been resolved. Jun 18, 03:11 PDT Monitoring - A fix has been implemented and we are monitoring the results. Jun 18, 02:53 PDT Identified - The issue has been identified and a fix is being implemented. Jun 18, 02:11 PDT Update - We are continuing to investigate this issue. Jun 18, 01:34 PDT Investigating - Customers using the events/logs APIs or viewing logs in the customer portal may see delays in some events appearing. These delays are
Started Jun 16, 2026 — Resolved Jun 16, 2026
Jun 16, 10:34 PDT Resolved - This incident has been resolved. Jun 16, 09:16 PDT Monitoring - A fix has been implemented and we are monitoring the results. Jun 16, 08:48 PDT Update - We are continuing to investigate this issue. Jun 16, 08:08 PDT Update - We are continuing to investigate this issue. Jun 16, 07:28 PDT Investigating - Logs are currently experiencing delays of 15 minutes in Mailgun's US region. Outbound processing, inbound processing, and webhook delivery are operating n
Recent Postmark incidents
Recent status page incidents for Postmark
Started Jul 6, 2026 — Resolved Jul 7, 2026
We've now resolved the incident. Thanks for your patience.
Started Jun 11, 2026 — Resolved Jun 12, 2026
All previously backlogged events have been processed. The issue occurred starting on June 11th at approximately 3:36am to June 12th 1:01pm CT (June 11th 08:36 – June 12th 18:01 UTC). Thank you for your patience. We will continue to improve our systems.
Started Jun 4, 2026 — Resolved Jun 5, 2026
The backlog of messages have been sent and system performance has returned to its expected state. Sending delays occurred between 4:50 – 6:35pm CT (21:50 – 23:35 UTC) for both transactional and broadcast mail. Engineering will continue to monitor.
Started Jun 1, 2026 — Resolved Jun 2, 2026
The issue has been resolved. Thank for your patience.
Started May 28, 2026 — Resolved May 28, 2026
The issue has been resolved.
Pros and cons
Mailgun
Postmark
Pros
- Well-written documentation with comprehensive guides and best practices for deliverability
- Robust deliverability support with optional expert pairing to optimize sending
- Powerful inbound email processing with customizable routing rules
- Trusted by Lyft, American Express, and Wikipedia since 2010
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
- Requires familiarity with email protocols and API integrations
- Pricing tiers can be confusing
- Email template features are basic without the Mailjet editor
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 the difference between Mailgun and Postmark?
Mailgun is a developer-focused email API platform owned by Sinch, known for flexible sending and receiving capabilities. Postmark is a transactional email service focused on fast, reliable delivery with transparent pricing. Mailgun is best suited for developer-focused sending + receiving, while Postmark is geared toward transactional email.
Which is cheaper, Mailgun or Postmark?
Free tier includes 100 emails per day with no expiration. Paid plans start at $15/month for 10,000 emails with overages at $1.80/1K. 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+. The best value depends on your sending volume. Use the pricing calculator above to compare costs at your expected volume.
Which is faster, Mailgun or Postmark?
Based on real-world data from Knock, Mailgun has a median API response time (p50) of 136ms compared to 4ms for Postmark.
Which is more reliable, Mailgun or Postmark?
From April 13th to July 12th, Mailgun showed an error rate of 0.00% while Postmark showed 0.00%. Both rates are within acceptable thresholds for production email delivery, and Knock automatically retries failed requests to minimize the impact of transient errors.
Which is more popular, Mailgun or Postmark?
On the Knock platform, Mailgun handled 100M–500M messages from April 13th to July 12th compared to 25M–100M for Postmark. Mailgun volume has remained stable, while Postmark is seeing declining volume.
Can I use both Mailgun and Postmark together?
Yes. Knock enables you to integrate multiple email providers into a single notification workflow. You can use Mailgun and Postmark side by side, route traffic between them, or migrate from one to the other without changing your application code.
What are the main pros and cons of Mailgun vs Postmark?
Mailgun strengths include well-written documentation with comprehensive guides and best practices for deliverability and robust deliverability support with optional expert pairing to optimize sending. Postmark 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, Mailgun drawbacks include requires familiarity with email protocols and api integrations, while Postmark drawbacks include no visual drag-and-drop email editor.
Use either provider with Knock
Knock enables you to integrate Mailgun, Postmark, or any combination of email providers into a single notification workflow. Manage templates, orchestrate cross-channel delivery, and switch providers without changing your code.