Mailjet vs Postmark
Compare Mailjet 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) |
|---|---|---|---|---|
| <1M | 6th of 10 → | 0 | 1 |
| 25M–100M | 4th of 10 → | 5 | 12 |
From May 24th to August 22nd, Knock routed <1M messages through Mailjet and 25M–100M through Postmark. Mailjet reported 1 status page update over the last 90 days, while Postmark reported 12.
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 May 24th to August 22nd. The top-line number is an average of these daily values: Mailjet averaged 399ms compared to 9ms for Postmark. Mailjet's highest daily p50 was 479ms; Postmark's was 62ms. Postmark is 390ms 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, Mailjet has a p90 of 604ms compared to 83ms for Postmark. The highest daily p90 was 18372ms for Mailjet and 222ms for Postmark. Postmark handles these slower requests 521ms 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, Mailjet reached 5289ms at p99 while Postmark reached 444ms. The highest daily p99 was 20295ms for Mailjet and 8081ms 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% |
|---|---|---|---|---|---|
| 0.03% | 12.20% | Aug 1 | 83 | 8 |
| 0.01% | 0.08% | Jul 24 | 72 | 15 |
Averaged across the date range, Mailjet shows a 0.03% daily error rate compared to 0.01% for Postmark. The highest single-day error rate was 12.20% for Mailjet and 0.08% 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 Mailjet incidents
Recent status page incidents for Mailjet
Started Jun 5, 2026 — Resolved Jun 5, 2026
Jun 5, 10:33 UTC Resolved - This incident has been resolved. Jun 5, 10:26 UTC Monitoring - A fix has been implemented and we are monitoring the results. Jun 5, 10:25 UTC Identified - The issue has been identified and a fix is being implemented. Jun 5, 10:01 UTC Investigating - We are currently investigating this issue.
Recent Postmark incidents
Recent status page incidents for Postmark
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.
Started Jul 27, 2026 — Resolved Jul 28, 2026
The scheduled maintenance is now underway. We'll keep you updated on our progress.
Pros and cons
Mailjet
Postmark
Pros
- Hybrid support for both marketers and developers in a single platform
- Unique real-time collaboration features for team-based template editing
- EU-only data processing for companies with strict data residency requirements
- Powers email delivery for over 130,000 companies including Microsoft and DHL
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
- Activated automation workflows cannot be edited, requiring new workflows for any changes
- Some analytics and deliverability tools are locked behind higher pricing plans
- Deliverability can lag behind specialists like Postmark
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 Mailjet and Postmark?
Mailjet is a collaborative email platform with real-time editing and combined transactional and marketing capabilities. Postmark is a transactional email service focused on fast, reliable delivery with transparent pricing. Mailjet is best suited for team collaboration + marketing, while Postmark is geared toward transactional email.
Which is cheaper, Mailjet or Postmark?
Free tier includes 200 emails per day (6,000/month). Paid plans start at $17/month for 15,000 emails with no daily limit. Premium plans start at $105/month for 100,000 emails. 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, Mailjet or Postmark?
Based on real-world data from Knock, Mailjet has a median API response time (p50) of 399ms compared to 9ms for Postmark.
Which is more reliable, Mailjet or Postmark?
From May 24th to August 22nd, Mailjet showed an error rate of 0.03% while Postmark showed 0.01%. 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, Mailjet or Postmark?
On the Knock platform, Mailjet handled <1M messages from May 24th to August 22nd compared to 25M–100M for Postmark. Mailjet volume has remained stable, while Postmark volume has remained stable.
Can I use both Mailjet and Postmark together?
Yes. Knock enables you to integrate multiple email providers into a single notification workflow. You can use Mailjet 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 Mailjet vs Postmark?
Mailjet strengths include hybrid support for both marketers and developers in a single platform and unique real-time collaboration features for team-based template editing. 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, Mailjet drawbacks include activated automation workflows cannot be edited, requiring new workflows for any changes, while Postmark drawbacks include no visual drag-and-drop email editor.
Use either provider with Knock
Knock enables you to integrate Mailjet, 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.