MailerSend vs Mailgun
Compare MailerSend and Mailgun 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 | 7th of 10 → | 0 | 1 |
| 100M–500M | 5th of 10 → | 6 | 14 |
From June 12th to September 10th, Knock routed <1M messages through MailerSend and 100M–500M through Mailgun. MailerSend reported 1 status page update over the last 90 days, while Mailgun reported 14.
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 |
|---|---|---|---|---|
| 110ms | 307ms | 359ms | 739ms |
| 120ms | 171ms | 187ms | 220ms |
The chart above shows each provider's daily median response time (p50) from June 12th to September 10th. The top-line number is an average of these daily values: MailerSend averaged 110ms compared to 120ms for Mailgun. MailerSend's highest daily p50 was 724ms; Mailgun's was 130ms. Both providers deliver comparable response times for the typical request.
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 307ms compared to 171ms for Mailgun. The highest daily p90 was 3166ms for MailerSend and 197ms for Mailgun. Mailgun handles these slower requests 136ms 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 739ms at p99 while Mailgun reached 220ms. The highest daily p99 was 24436ms 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% | 0.27% | Jul 21 | 90 | 1 |
| 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 0.27% 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 Jul 1, 2026 — Resolved Jul 1, 2026
Status: Complete Maintenance has completed Affected components Delivery time (Under maintenance) Email sending API (Under maintenance) Bulk endpoint (Under maintenance) SMTP (Under maintenance)
Recent Mailgun incidents
Recent status page incidents for Mailgun
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
Started Aug 31, 2026 — Resolved Aug 31, 2026
Aug 31, 15:01 PDT Resolved - Event queues have caught up and events are processing normally. Aug 31, 14:28 PDT Update - The event processing backlog is steadily decreasing, and we’re continuing to monitor the recovery. We expect all delays to be resolved within the hour. Aug 31, 13:43 PDT Update - The event processing backlog is steadily decreasing, and we’re continuing to monitor the recovery. Aug 31, 13:13 PDT Update - The event processing backlog is steadily decreasing, and we’re co
Started Aug 27, 2026 — Resolved Aug 27, 2026
Aug 27, 14:16 PDT Resolved - This incident has been resolved. Aug 27, 14:00 PDT Monitoring - A fix has been implemented and we are monitoring the results. Aug 27, 13:45 PDT Identified - We have identified the issue and working on restoring service. Aug 27, 13:38 PDT Investigating - We are currently investigating an outage in our EU datacenter
Started Aug 20, 2026 — Resolved Aug 20, 2026
Aug 20, 10:31 PDT Resolved - This incident has been resolved. Aug 20, 10:09 PDT Update - GCP has put a mitigation in place, we are monitoring the results. At this time we are experiencing no impacts. All delayed webhooks and logs have been processed. Aug 20, 09:30 PDT Update - Outbound delivery is operating normally. Currently there are delays for event logs and some webhooks. Aug 20, 09:19 PDT Monitoring - Mailgun is monitoring service impacts in GCP's us-west1 region. We are routing
Pros and cons
MailerSend
Mailgun
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
- 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
- Available integrations with other tools are basic and limited
- Fewer advanced features than enterprise platforms
- Smaller ecosystem compared to established competitors
Cons
- Requires familiarity with email protocols and API integrations
- Pricing tiers can be confusing
- Email template features are basic without the Mailjet editor
Frequently asked questions
What is the difference between MailerSend and Mailgun?
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.
Which is cheaper, MailerSend or Mailgun?
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 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.
Which is faster, MailerSend or Mailgun?
Based on real-world data from Knock, MailerSend has a median API response time (p50) of 110ms compared to 120ms for Mailgun.
Which is more reliable, MailerSend or Mailgun?
From June 12th to September 10th, 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.
Which is more popular, MailerSend or Mailgun?
On the Knock platform, MailerSend handled <1M messages from June 12th to September 10th compared to 100M–500M for Mailgun. MailerSend volume has remained stable, while Mailgun volume has remained stable.
Can I use both MailerSend and Mailgun together?
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.
What are the main pros and cons of MailerSend vs Mailgun?
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.
Use either provider with Knock
Knock enables you to integrate MailerSend, Mailgun, or any combination of email providers into a single notification workflow. Manage templates, orchestrate cross-channel delivery, and switch providers without changing your code.