Compare MailerSend against Mailjet API performance
Compare real-time performance, reliability, and uptime benchmarks for MailerSend and Mailjet, powered by proprietary data from billions of messages sent through Knock.
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 | 8th of 10 → | 0 | 2 |
 | <1M | 6th of 10 → | 0 | 2 |
From August 13th to November 11th, Knock routed <1M messages through MailerSend and <1M through Mailjet. MailerSend reported 2 status page updates over the last 90 days, while Mailjet reported 2.
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.
| Provider | Median (p50) | p90 | p95 | p99 |
|---|---|---|---|---|
| 269ms | 467ms | 696ms | 1635ms |
| 406ms | 594ms | 608ms | 746ms |
The chart above shows each provider's daily median response time (p50) from August 13th to November 11th. The top-line number is an average of these daily values: MailerSend averaged 269ms compared to 406ms for Mailjet. MailerSend's highest daily p50 was 730ms; Mailjet's was 446ms. MailerSend is 137ms 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, MailerSend has a p90 of 467ms compared to 594ms for Mailjet. The highest daily p90 was 3166ms for MailerSend and 1020ms for Mailjet. MailerSend handles these slower requests 127ms 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, MailerSend reached 1635ms at p99 while Mailjet reached 746ms. The highest daily p99 was 43537ms for MailerSend and 2503ms for Mailjet, indicating the worst-case response time during spikes or provider-side congestion. Mailjet 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% | 0.00% | Aug 13 | 91 | 0 |
| 0.00% | 0.00% | Aug 13 | 91 | 0 |
Averaged across the date range, MailerSend shows a 0.00% daily error rate compared to 0.00% for Mailjet. The highest single-day error rate was 0.00% for MailerSend and 0.00% for Mailjet. 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 MailerSend incidents
Recent status page incidents for MailerSend
Started Oct 11, 2026 — Resolved Oct 11, 2026
Status: Complete (Sun, 11 Oct 2026 07:10:00 GMT - Sun, 11 Oct 2026 07:40:00 GMT) Maintenance has completed Affected components Bulk endpoint (Operational) SMTP (Operational) Email activity (Operational) Delivery time (Operational) Email sending API (Operational) Email analytics (Operational) Deliverability rate (Operational) MailerSend APP (Operational)
Started Sep 21, 2026 — Resolved Sep 21, 2026
Status: Complete (Mon, 21 Sep 2026 07:00:00 GMT - Mon, 21 Sep 2026 07:05:00 GMT) Maintenance has completed Affected components Bulk endpoint (Operational) SMTP (Operational) Delivery time (Operational) Email sending API (Operational) Inbound routing (Operational)
Recent Mailjet incidents
Recent status page incidents for Mailjet
Started Sep 23, 2026 — Resolved Sep 23, 2026
Sep 23, 05:00 UTC Completed - The scheduled maintenance has been completed. Sep 23, 04:00 UTC In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Sep 15, 08:10 UTC Scheduled - We’ll be performing scheduled infrastructure maintenance on Wednesday, September 23, starting at 4:00 AM UTC. The estimated impact duration is 30 minutes. During this window, you won't be able to log in or send new messages via SMTP or API. Don't worry, any emails alr
Started Sep 4, 2026 — Resolved Sep 4, 2026
Sep 4, 12:55 UTC Resolved - This incident has been resolved. Sep 4, 12:23 UTC Monitoring - Starting around 08:00 UTC, Microsoft began experiencing an incident causing an increased volume of deferred emails across all M365 regions. The affected responses are returning "451 4.7.500 Server busy". Our teams are actively monitoring the situation. Sending to other email providers is not affected.
Pros and cons
Compare the strengths and tradeoffs between MailerSend and Mailjet.
MailerSend
Pros
- Designed for both developers and business users with API and visual editor
- Modern, intuitive UI that is easier to navigate than older platforms
- Multi-channel support with native email and SMS transactional messaging
- Affordable Hobby plan at $7/month for 5,000 emails with low overage rates
Cons
- Available integrations with other tools are basic and limited
- Fewer advanced features than enterprise platforms
- Smaller ecosystem compared to established competitors
Mailjet
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
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
Pricing comparison
Compare MailerSend and Mailjet as your email volume grows.
Frequently asked questions
Mailersend is an intuitive transactional email and SMS service by Mailgun, designed for growing businesses. Mailjet is a collaborative email platform with real-time editing and combined transactional and marketing capabilities. MailerSend is best suited for growing saas + e-commerce, while Mailjet is geared toward team collaboration + marketing.
Free tier includes 500 emails per month. Hobby is $7/month for 5,000 emails, with extra email at $1.50 per 1,000, and does not extend to 50,000 emails. Starter starts at $35/month for 50,000 emails and ends at 1 million. Professional starts at $110/month and published pricing ends at 2 million. 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. The best value depends on your sending volume. Use the pricing calculator above to compare costs at your expected volume.
Based on real-world data from Knock, MailerSend has a median API response time (p50) of 269ms compared to 406ms for Mailjet.
From August 13th to November 11th, MailerSend showed an error rate of 0.00% while Mailjet 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.
On the Knock platform, MailerSend handled <1M messages from August 13th to November 11th compared to <1M for Mailjet. MailerSend volume has remained stable, while Mailjet volume has remained stable.
Yes. Knock enables you to integrate multiple email providers into a single notification workflow. You can use MailerSend and Mailjet side by side, route traffic between them, or migrate from one to the other without changing your application code.
MailerSend strengths include designed for both developers and business users with api and visual editor and modern, intuitive ui that is easier to navigate than older platforms. 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. On the other hand, MailerSend drawbacks include available integrations with other tools are basic and limited, while Mailjet drawbacks include activated automation workflows cannot be edited, requiring new workflows for any changes.