Compare MailerSend against Mailgun API performance
Compare real-time performance, reliability, and uptime benchmarks for MailerSend and Mailgun, 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 |
 | 100M–500M | 5th of 10 → | 1 | 9 |
From August 13th to November 11th, Knock routed <1M messages through MailerSend and 100M–500M through Mailgun. MailerSend reported 2 status page updates over the last 90 days, while Mailgun reported 9.
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 |
| 121ms | 170ms | 191ms | 225ms |
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 121ms for Mailgun. MailerSend's highest daily p50 was 730ms; Mailgun's was 133ms. Mailgun is 148ms 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 170ms for Mailgun. The highest daily p90 was 3166ms for MailerSend and 197ms for Mailgun. Mailgun handles these slower requests 297ms 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 Mailgun reached 225ms. The highest daily p99 was 43537ms for MailerSend and 506ms for Mailgun, indicating the worst-case response time during spikes or provider-side congestion. Mailgun 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% | 0.01% | Aug 27 | 90 | 0 |
Averaged across the date range, MailerSend shows a 0.00% daily error rate compared to 0.00% for Mailgun. The highest single-day error rate was 0.00% for MailerSend and 0.01% for Mailgun. 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 Mailgun incidents
Recent status page incidents for Mailgun
Started Oct 28, 2026 — Resolved Oct 28, 2026
Oct 28, 02:40 PDT Resolved - This incident has been resolved. Oct 28, 02:27 PDT Monitoring - A fix has been implemented and we are monitoring the results. Oct 28, 01:54 PDT Identified - The issue has been identified and a fix is being implemented. Oct 28, 01:36 PDT Investigating - We are currently investigating this issue.
Started Sep 30, 2026 — Resolved Sep 30, 2026
Sep 30, 02:58 PDT Resolved - This incident has been resolved. Sep 30, 02:48 PDT Monitoring - A fix has been implemented and we are monitoring the results. Sep 30, 02:38 PDT Identified - The issue has been identified and a fix is being implemented. Sep 30, 02:16 PDT Investigating - We are currently investigating this issue.
Started Sep 14, 2026 — Resolved Sep 14, 2026
Sep 14, 03:13 PDT Resolved - This incident has been resolved. Sep 14, 02:55 PDT Monitoring - A fix has been implemented and we are monitoring the results. Sep 14, 02:15 PDT Investigating - We are currently investigating this issue.
Started Sep 4, 2026 — Resolved Sep 4, 2026
Sep 4, 07:33 PDT Resolved - This incident has been resolved. Sep 4, 07:21 PDT Monitoring - A fix has been implemented and we are monitoring the results. Sep 4, 07:16 PDT Investigating - We are currently investigating this issue.
Started Sep 4, 2026 — Resolved Sep 4, 2026
Sep 4, 05:54 PDT Resolved - Microsoft has resolved the underlying issue, we are seeing deliveries to M365 process normally. Sep 4, 05:22 PDT Update - We are continuing to monitor for any further issues. Sep 4, 05:20 PDT 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. Send
Pros and cons
Compare the strengths and tradeoffs between MailerSend and Mailgun.
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
Mailgun
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
Cons
- Requires familiarity with email protocols and API integrations
- Pricing tiers can be confusing
- Email template features are basic without the Mailjet editor
Pricing comparison
Compare MailerSend and Mailgun as your email volume grows.
Frequently asked questions
Mailersend is an intuitive transactional email and SMS service by Mailgun, designed for growing businesses. Mailgun is a developer-focused email API platform owned by Sinch, known for flexible sending and receiving capabilities. MailerSend is best suited for growing saas + e-commerce, while Mailgun is geared toward developer-focused sending + receiving.
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 100 emails per day with no expiration. Paid plans start at $15/month for 10,000 emails with overages at $1.80/1K. 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 121ms for Mailgun.
From August 13th to November 11th, MailerSend showed an error rate of 0.00% while Mailgun 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 100M–500M for Mailgun. MailerSend volume has remained stable, while Mailgun volume has remained stable.
Yes. Knock enables you to integrate multiple email providers into a single notification workflow. You can use MailerSend and Mailgun 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. 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. On the other hand, MailerSend drawbacks include available integrations with other tools are basic and limited, while Mailgun drawbacks include requires familiarity with email protocols and api integrations.