MailerSend vs Mailjet
Compare MailerSend and Mailjet 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 | 9th of 10 ↓ | 0 | 3 |
| <1M | 6th of 10 ↓ | 0 | 1 |
From February 17th to May 18th, Knock routed <1M messages through MailerSend and <1M through Mailjet. MailerSend reported 3 status page updates over the last 90 days, while Mailjet reported 1.
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 |
|---|---|---|---|---|
| 247ms | 520ms | 563ms | 785ms |
| 413ms | 544ms | 600ms | 766ms |
The chart above shows each provider's daily median response time (p50) from February 17th to May 18th. The top-line number is an average of these daily values: MailerSend averaged 247ms compared to 413ms for Mailjet. MailerSend's highest daily p50 was 826ms; Mailjet's was 490ms. MailerSend is 166ms 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 520ms compared to 544ms for Mailjet. The highest daily p90 was 1811ms for MailerSend and 20309ms for Mailjet. MailerSend handles these slower requests 24ms 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 785ms at p99 while Mailjet reached 766ms. The highest daily p99 was 12094ms for MailerSend and 20345ms for Mailjet, indicating the worst-case response time during spikes or provider-side congestion. Both providers exhibit comparable tail response times, meaning neither is significantly more prone to outlier slowdowns.
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% |
|---|---|---|---|---|---|
| 0.01% | 0.07% | Apr 29 | 86 | 4 |
| 0.13% | 12.99% | Apr 13 | 88 | 3 |
Averaged across the date range, MailerSend shows a 0.01% daily error rate compared to 0.13% for Mailjet. The highest single-day error rate was 0.07% for MailerSend and 12.99% for Mailjet. MailerSend demonstrates a lower error rate, indicating slightly more consistent availability during this period. 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 Apr 12, 2026 — Resolved Apr 12, 2026
Status: Complete Maintenance has completed Affected components MailerSend APP (Under maintenance)
Started Mar 3, 2026 — Resolved Mar 3, 2026
Status: Complete Maintenance has completed Affected components SMTP (Under maintenance) Delivery time (Under maintenance) Email sending API (Under maintenance) Deliverability rate (Under maintenance) Bulk endpoint (Under maintenance)
Started Feb 19, 2026 — Resolved Feb 19, 2026
Status: Resolved The issue has been resolved and systems have returned to normal. We’ll continue monitoring to ensure ongoing stability. Thank you for your patience. Affected components MailerSend APP (Operational)
Recent Mailjet incidents
Recent status page incidents for Mailjet
Started Apr 16, 2026 — Resolved Apr 16, 2026
Apr 16, 03:30 UTC Completed - The scheduled maintenance has been completed.Apr 16, 02:30 UTC In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary.Apr 13, 16:16 UTC Scheduled - We’ll be performing scheduled infrastructure maintenance on Thursday, April 16, starting at 2:30 AM UTC. The estimated impact duration is 15 to 20 minutes. During this window, you won't be able to log in or send new messages via API. Don't worry, any emails already submitted w
Pros and cons
MailerSend
Mailjet
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
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
- Available integrations with other tools are basic and limited
- Fewer advanced features than enterprise platforms
- Smaller ecosystem compared to established competitors
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
Frequently asked questions
What is the difference between MailerSend and Mailjet?
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.
Which is cheaper, MailerSend or Mailjet?
Free tier includes 500 emails per month. Paid plans start at $7/month for 5,000 emails on the Hobby plan, with the Starter plan at $35/month for 50,000 emails. 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.
Which is faster, MailerSend or Mailjet?
Based on real-world data from Knock, MailerSend has a median API response time (p50) of 247ms compared to 413ms for Mailjet.
Which is more reliable, MailerSend or Mailjet?
From February 17th to May 18th, MailerSend showed an error rate of 0.01% while Mailjet showed 0.13%. 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, MailerSend or Mailjet?
On the Knock platform, MailerSend handled <1M messages from February 17th to May 18th compared to <1M for Mailjet. MailerSend is currently seeing declining volume, while Mailjet is seeing declining volume.
Can I use both MailerSend and Mailjet together?
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.
What are the main pros and cons of MailerSend vs Mailjet?
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.
Use either provider with Knock
Knock enables you to integrate MailerSend, Mailjet, or any combination of email providers into a single notification workflow. Manage templates, orchestrate cross-channel delivery, and switch providers without changing your code.