Compare Resend against Sparkpost API performance
Compare real-time performance, reliability, and uptime benchmarks for Resend and Sparkpost, 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) |
|---|---|---|---|---|
 | 10M–25M | 1st of 10 → | 2 | 2 |
 | <1M | 10th of 10 ↓ | 2 | 8 |
From August 13th to November 11th, Knock routed 10M–25M messages through Resend and <1M through Sparkpost. Resend reported 2 status page updates over the last 90 days, while Sparkpost reported 8.
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 August 13th to November 11th. The top-line number is an average of these daily values: Resend averaged 70ms compared to 317ms for Sparkpost. Resend's highest daily p50 was 96ms; Sparkpost's was 525ms. Resend is 247ms 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, Resend has a p90 of 102ms compared to 540ms for Sparkpost. The highest daily p90 was 146ms for Resend and 630ms for Sparkpost. Resend handles these slower requests 438ms 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, Resend reached 304ms at p99 while Sparkpost reached 721ms. The highest daily p99 was 1793ms for Resend and 931ms for Sparkpost, indicating the worst-case response time during spikes or provider-side congestion. Resend 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% | 0.09% | Oct 1 | 89 | 2 |
| 0.00% | 0.00% | Aug 13 | 91 | 0 |
Averaged across the date range, Resend shows a 0.00% daily error rate compared to 0.00% for Sparkpost. The highest single-day error rate was 0.09% for Resend and 0.00% for Sparkpost. 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 Resend incidents
Recent status page incidents for Resend
Started Oct 26, 2026 — Resolved Oct 26, 2026
Status: Resolved Email status updates are processing normally again. All delayed updates have been delivered, and no data was lost. Affected components Email Events (Operational)
Started Oct 23, 2026 — Resolved Oct 23, 2026
Status: Resolved We have resolved the underlying issue and service has been resumed. Affected components Single Email (Operational) Broadcast Emails (Operational) Batch Emails (Operational) Scheduled Emails (Operational)
Recent Sparkpost incidents
Recent status page incidents for Sparkpost
Started Oct 31, 2026 — Resolved Oct 31, 2026
Oct 31, 13:23 EDT Resolved - This incident has been resolved. Oct 30, 16:02 EDT Identified - We have identified the issue and are working on a resolution; delivery latencies are recovering. Oct 30, 15:21 EDT Investigating - We are investigating a small increase in delivery latency for some outbound messages. (NOTE: This does not impact our customers hosted in the EU.)
Started Oct 28, 2026 — Resolved Oct 28, 2026
Oct 28, 16:37 EDT Resolved - This incident has been resolved. Oct 28, 16:37 EDT Monitoring - A fix was implemented and we are seeing sustained delivery recovery. Oct 28, 16:03 EDT Identified - We are continuing to work on a fix for this issue. Oct 28, 16:00 EDT Monitoring - A fix has been implemented and we are monitoring the results. Oct 28, 15:48 EDT Identified - The issue has been identified and a fix is being implemented. Oct 28, 15:37 EDT Investigating - We are investigating
Started Oct 11, 2026 — Resolved Oct 11, 2026
Oct 11, 16:57 EDT Resolved - This incident has been resolved. Oct 11, 14:17 EDT Monitoring - A fix has been implemented and we are monitoring the results. Oct 11, 14:17 EDT Update - We are continuing to work on a fix for this issue. Oct 11, 14:09 EDT Update - We are continuing to rollout the new root signing keys from ICANN. We continue to see recovery across our global clusters. Oct 11, 13:51 EDT Identified - We are investigating an increase in delayed (deferred) messages in both
Started Oct 1, 2026 — Resolved Oct 1, 2026
Oct 1, 13:36 EDT Resolved - This issue has been resolved. Since our changes went in, we've seen no further delivery delays, including through peak sending periods. Email is being delivered normally. We apologize for the disruption and thank you for your patience. Oct 1, 13:16 EDT Monitoring - We've made changes to address the intermittent delivery delays. Since then, email has been delivered without delay, including during peak sending periods that previously caused the slowdowns. We're wa
Started Sep 17, 2026 — Resolved Sep 17, 2026
Sep 17, 06:00 EDT Resolved - This incident has been resolved. Sep 17, 05:47 EDT Monitoring - A fix has been implemented and we are monitoring the results. Sep 17, 05:06 EDT Investigating - We are investigating an increase in delivery latency for some outbound messages. (NOTE: This does not impact our customers hosted in the EU.)
Pros and cons
Compare the strengths and tradeoffs between Resend and Sparkpost.
Resend
Pros
- Beautiful documentation with attention to detail and great developer experience
- Created and maintain React Email, the go-to framework for building email templates in React
- Minimalist, developer-optimized platform that avoids bloat with a focused UI
- Transparent observability with real-time visibility into sends, failures, and engagement
Cons
- Newer and less battle-tested compared to incumbents like Mailgun or SendGrid
- Fewer enterprise features than established providers
- Limited marketing email capabilities
Sparkpost
Pros
- Delivers nearly 40% of all commercial email worldwide
- Subaccount support for isolated sending streams under one billing account
- On-premise mail sending solution available for very high volume workloads
- Great analytics tools with predictive health scores for email deliverability
Cons
- Documentation can be hard to navigate with less beginner-friendly getting started content
- Higher price point than basic providers
- Now part of Bird (formerly MessageBird), which may affect product direction
Pricing comparison
Compare Resend and Sparkpost as your email volume grows.
Frequently asked questions
Resend is a modern email API built for developers, with React Email support and a focus on simplicity. SparkPost is a data-driven email delivery platform with advanced analytics and predictive tools for high-volume senders. Resend is best suited for developer-first, react teams, while Sparkpost is geared toward data-driven, high-volume.
Free tier includes 3,000 emails per month and 100 emails per day. Paid plans start at $20/month for 50,000 emails with overages at $0.90/1K on Pro, scaling down to $0.46/1K on Scale 2.5M. Free tier includes 500 emails per month with community support. Paid plans start at $20/month for 50,000 emails with premium deliverability features. 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, Resend has a median API response time (p50) of 70ms compared to 317ms for Sparkpost.
From August 13th to November 11th, Resend showed an error rate of 0.00% while Sparkpost 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, Resend handled 10M–25M messages from August 13th to November 11th compared to <1M for Sparkpost. Resend volume has remained stable, while Sparkpost is seeing declining volume.
Yes. Knock enables you to integrate multiple email providers into a single notification workflow. You can use Resend and Sparkpost side by side, route traffic between them, or migrate from one to the other without changing your application code.
Resend strengths include beautiful documentation with attention to detail and great developer experience and created and maintain react email, the go-to framework for building email templates in react. Sparkpost strengths include delivers nearly 40% of all commercial email worldwide and subaccount support for isolated sending streams under one billing account. On the other hand, Resend drawbacks include newer and less battle-tested compared to incumbents like mailgun or sendgrid, while Sparkpost drawbacks include documentation can be hard to navigate with less beginner-friendly getting started content.