Mailgun vs Mandrill
Compare Mailgun and Mandrill 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) |
|---|---|---|---|---|
| 100M–500M | 5th of 10 → | 6 | 14 |
| <1M | 8th of 10 → | 0 | 0 |
From June 12th to September 10th, Knock routed 100M–500M messages through Mailgun and <1M through Mandrill. Mailgun reported 14 status page updates over the last 90 days, while Mandrill reported 0.
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 June 12th to September 10th. The top-line number is an average of these daily values: Mailgun averaged 120ms compared to 404ms for Mandrill. Mailgun's highest daily p50 was 130ms; Mandrill's was 568ms. Mailgun is 284ms 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, Mailgun has a p90 of 171ms compared to 732ms for Mandrill. The highest daily p90 was 197ms for Mailgun and 1781ms for Mandrill. Mailgun handles these slower requests 561ms 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, Mailgun reached 220ms at p99 while Mandrill reached 1854ms. The highest daily p99 was 506ms for Mailgun and 10903ms for Mandrill, 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% | 0.01% | Aug 27 | 90 | 0 |
| 0.00% | 0.02% | Sep 2 | 90 | 1 |
Averaged across the date range, Mailgun shows a 0.00% daily error rate compared to 0.00% for Mandrill. The highest single-day error rate was 0.01% for Mailgun and 0.02% for Mandrill. 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 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
Recent Mandrill incidents
Recent status page incidents for Mandrill
No incidents reported in the last 90 days
Pros and cons
Mailgun
Mandrill
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
Pros
- Friendly, well-laid-out developer documentation that makes integration straightforward
- Global infrastructure for fast delivery with dedicated IPs and IP address pools
- Solid analytics with reports on deliverability, opens, clicks, bounces, and rejections
- Reuse Mailchimp templates for transactional email with deep ecosystem integration
Cons
- Requires familiarity with email protocols and API integrations
- Pricing tiers can be confusing
- Email template features are basic without the Mailjet editor
Cons
- Requires an existing Mailchimp Standard or Premium subscription
- Not available as a standalone service
- Higher cost than some dedicated transactional services
Frequently asked questions
What is the difference between Mailgun and Mandrill?
Mailgun is a developer-focused email API platform owned by Sinch, known for flexible sending and receiving capabilities. Mandrill is a transactional email add-on for Mailchimp, suited for teams already using the Mailchimp platform. Mailgun is best suited for developer-focused sending + receiving, while Mandrill is geared toward mailchimp users needing transactional.
Which is cheaper, Mailgun or Mandrill?
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. Included as an add-on to Mailchimp Standard or Premium plans. Pricing is based on email blocks of 25,000 emails, starting at $20/block. Volume discounts apply: $18/block above 500K, scaling down to $10/block above 4M. The best value depends on your sending volume. Use the pricing calculator above to compare costs at your expected volume.
Which is faster, Mailgun or Mandrill?
Based on real-world data from Knock, Mailgun has a median API response time (p50) of 120ms compared to 404ms for Mandrill.
Which is more reliable, Mailgun or Mandrill?
From June 12th to September 10th, Mailgun showed an error rate of 0.00% while Mandrill 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, Mailgun or Mandrill?
On the Knock platform, Mailgun handled 100M–500M messages from June 12th to September 10th compared to <1M for Mandrill. Mailgun volume has remained stable, while Mandrill volume has remained stable.
Can I use both Mailgun and Mandrill together?
Yes. Knock enables you to integrate multiple email providers into a single notification workflow. You can use Mailgun and Mandrill 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 Mailgun vs Mandrill?
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. Mandrill strengths include friendly, well-laid-out developer documentation that makes integration straightforward and global infrastructure for fast delivery with dedicated ips and ip address pools. On the other hand, Mailgun drawbacks include requires familiarity with email protocols and api integrations, while Mandrill drawbacks include requires an existing mailchimp standard or premium subscription.
Use either provider with Knock
Knock enables you to integrate Mailgun, Mandrill, or any combination of email providers into a single notification workflow. Manage templates, orchestrate cross-channel delivery, and switch providers without changing your code.