Mandrill vs SendGrid
Compare Mandrill and SendGrid 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–10M | 8th of 10 ↓ | 0 | 0 |
| 500M+ | 2nd of 10 → | 7 | 25 |
From February 17th to May 18th, Knock routed 1M–10M messages through Mandrill and 500M+ through SendGrid. Mandrill reported 0 status page updates over the last 90 days, while SendGrid reported 25.
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 February 17th to May 18th. The top-line number is an average of these daily values: Mandrill averaged 137ms compared to 22ms for SendGrid. Mandrill's highest daily p50 was 263ms; SendGrid's was 24ms. SendGrid is 115ms 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, Mandrill has a p90 of 369ms compared to 76ms for SendGrid. The highest daily p90 was 524ms for Mandrill and 98ms for SendGrid. SendGrid handles these slower requests 293ms 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, Mandrill reached 859ms at p99 while SendGrid reached 407ms. The highest daily p99 was 1341ms for Mandrill and 2348ms for SendGrid, indicating the worst-case response time during spikes or provider-side congestion. SendGrid 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% |
|---|---|---|---|---|---|
| 0.02% | 0.43% | Apr 27 | 82 | 7 |
| 0.00% | 0.02% | Feb 18 | 86 | 3 |
Averaged across the date range, Mandrill shows a 0.02% daily error rate compared to 0.00% for SendGrid. The highest single-day error rate was 0.43% for Mandrill and 0.02% for SendGrid. 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 Mandrill incidents
Recent status page incidents for Mandrill
No incidents reported in the last 90 days
Recent SendGrid incidents
Recent status page incidents for SendGrid
Started May 14, 2026 — Resolved May 14, 2026
May 14, 10:47 PDT Resolved - Our engineers have monitored the fix and confirmed the issue with Sender Engagement Quality (SEQ) API endpoint has been resolved. All services are now operating normally at this time.May 14, 10:12 PDT Monitoring - Our engineers have implemented a fix and are monitoring system performance. SendGrid Engagement Quality API endpoint is now working as expected with API keys. We will provide another update in 30 minutes or as soon as more information becomes available.May
Started May 13, 2026 — Resolved May 13, 2026
May 12, 17:22 PDT Resolved - Our engineers have monitored the fix and confirmed all services are now operating normally.May 12, 16:48 PDT Monitoring - Between 16:10 PDT and 16:27 PDT on 05/12/2026, our engineers began investigating an issue with a subset of services experiencing 5xx errors. Users may have experienced issues when accessing subusers, authenticating domains and link branding records, accessing the account, and checking account stats. This does not impact mail send. Our engineer
Started May 12, 2026 — Resolved May 12, 2026
May 12, 11:20 PDT Resolved - Our engineers have monitored the fix and confirmed the issue with teammate account creation has been resolved. All services are now operating normally at this time.May 12, 10:13 PDT Monitoring - Our engineers have implemented a fix and are monitoring system performance. Teammates that were impacted by the issue need to request a new invite link and delete cache and cookies on their browsers before attempting to join again. We will provide another update in one hour o
Started May 8, 2026 — Resolved May 8, 2026
May 8, 01:09 PDT Resolved - Our engineers have monitored the fix and confirmed the issue with Mail delay has been resolved. All services are now operating normally at this timeMay 8, 00:04 PDT Update - Our engineering team has identified the root cause of the issue and is actively working on a resolution. Please note that new Mail Send requests are processing as expected and are not impacted. We will share another update within the next two hours, or sooner if additional information becomes av
Started May 6, 2026 — Resolved May 6, 2026
May 6, 16:22 PDT Resolved - Our engineers have monitored the fix and confirmed the issue with Twilio SendGrid invoices and the tax amounts has been resolved. All services are now operating normally at this time.May 6, 15:04 PDT Monitoring - Our engineers have implemented a fix and are monitoring system performance. We have resolved the tax calculation issue, and customer invoices have been corrected with the appropriate tax amounts. If you were overcharged, your refund will be automatically pr
Pros and cons
Mandrill
SendGrid
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
Pros
- Comprehensive documentation with SDKs for most major languages
- Rich analytics tools with programmatic API access to engagement data
- Strong focus on deliverability with AI-powered intelligent delivery
- Trusted by Uber, Booking.com, and Yelp for high-volume sending
Cons
- Requires an existing Mailchimp Standard or Premium subscription
- Not available as a standalone service
- Higher cost than some dedicated transactional services
Cons
- Extended email activity history requires a paid add-on
- Pricing can become complex at higher volumes
- Support response times vary by plan tier
Frequently asked questions
What is the difference between Mandrill and SendGrid?
Mandrill is a transactional email add-on for Mailchimp, suited for teams already using the Mailchimp platform. SendGrid is a cloud-based email delivery platform owned by Twilio, known for high-volume transactional and marketing email. Mandrill is best suited for mailchimp users needing transactional, while SendGrid is geared toward high-volume transactional + marketing.
Which is cheaper, Mandrill or SendGrid?
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. Free tier includes up to 100 emails per day for 60 days. Paid plans start at $19.95/month for 50,000 emails on the Essentials plan, with an Essentials 100K tier at $34.95/month. Pro plans with dedicated IPs start at $249/month for 300,000 emails. The best value depends on your sending volume. Use the pricing calculator above to compare costs at your expected volume.
Which is faster, Mandrill or SendGrid?
Based on real-world data from Knock, Mandrill has a median API response time (p50) of 137ms compared to 22ms for SendGrid.
Which is more reliable, Mandrill or SendGrid?
From February 17th to May 18th, Mandrill showed an error rate of 0.02% while SendGrid 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, Mandrill or SendGrid?
On the Knock platform, Mandrill handled 1M–10M messages from February 17th to May 18th compared to 500M+ for SendGrid. Mandrill is currently seeing declining volume, while SendGrid volume has remained stable.
Can I use both Mandrill and SendGrid together?
Yes. Knock enables you to integrate multiple email providers into a single notification workflow. You can use Mandrill and SendGrid 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 Mandrill vs SendGrid?
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. SendGrid strengths include comprehensive documentation with sdks for most major languages and rich analytics tools with programmatic api access to engagement data. On the other hand, Mandrill drawbacks include requires an existing mailchimp standard or premium subscription, while SendGrid drawbacks include extended email activity history requires a paid add-on.
Use either provider with Knock
Knock enables you to integrate Mandrill, SendGrid, or any combination of email providers into a single notification workflow. Manage templates, orchestrate cross-channel delivery, and switch providers without changing your code.