Resend vs Sparkpost
Compare Resend and Sparkpost 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) |
|---|---|---|---|---|
| 10M–25M | 1st of 10 → | 8 | 19 |
| <1M | 10th of 10 ↑ | 1 | 5 |
From April 14th to July 13th, Knock routed 10M–25M messages through Resend and <1M through Sparkpost. Resend reported 19 status page updates over the last 90 days, while Sparkpost reported 5.
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 April 14th to July 13th. The top-line number is an average of these daily values: Resend averaged 97ms compared to 281ms for Sparkpost. Resend's highest daily p50 was 122ms; Sparkpost's was 312ms. Resend is 184ms 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 164ms compared to 480ms for Sparkpost. The highest daily p90 was 221ms for Resend and 574ms for Sparkpost. Resend handles these slower requests 316ms 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 417ms at p99 while Sparkpost reached 623ms. The highest daily p99 was 10906ms for Resend This peak coincided with a major incident reported on Resend's status page (Degraded perfomance in Metrics). and 768ms 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% |
|---|---|---|---|---|---|
| 0.01% | 0.57% | Jul 1 | 84 | 4 |
| 0.00% | 0.42% | May 4 | 90 | 1 |
Averaged across the date range, Resend shows a 0.01% daily error rate compared to 0.00% for Sparkpost. The highest single-day error rate was 0.57% for Resend and 0.42% 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 Jul 12, 2026 — Resolved Jul 12, 2026
Status: Resolved We have resolved the underlying issue and service has been resumed. Affected components Automations (Operational)
Started Jul 10, 2026 — Resolved Jul 10, 2026
Status: Resolved We have resolved the underlying issue and service has been resumed. Affected components Single Email (Operational) Dashboard (Operational) SMTP (Operational) Broadcast Emails (Operational) Batch Emails (Operational) General API (Operational)
Started Jul 3, 2026 — Resolved Jul 3, 2026
Status: Resolved We have resolved the underlying issue and services have been recovered. Affected components Single Email (Operational) SMTP (Operational) Broadcast Emails (Operational) Batch Emails (Operational)
Started Jul 1, 2026 — Resolved Jul 1, 2026
Status: Resolved Our team has mitigated the issue and this incident is fully resolved. All services are operational. Affected components General API (Operational) Dashboard (Operational) SMTP (Operational) Broadcast Emails (Operational) Batch Emails (Operational) Webhooks (Operational) Website (Operational) Automations (Operational) Single Email (Operational) Email Events (Operational)
Started Jun 22, 2026 — Resolved Jun 22, 2026
Status: Resolved We have resolved the underlying issue and service has been resumed. Affected components Dashboard (Operational)
Recent Sparkpost incidents
Recent status page incidents for Sparkpost
Started Jun 29, 2026 — Resolved Jun 29, 2026
Jun 29, 12:46 EDT Resolved - This incident has been resolved. Jun 29, 12:05 EDT Monitoring - There was a combination of events that caused a short period of slowdown. That slowdown has already recovered and we are monitoring to ensure we do not see it again. Jun 29, 11:58 EDT Investigating - We are investigating the delay and the impact. We will post once we know more.
Started May 12, 2026 — Resolved May 12, 2026
May 12, 09:38 EDT Resolved - This incident has been resolved. May 12, 09:10 EDT Monitoring - A fix has been implemented and we are monitoring the results. May 12, 08:48 EDT Identified - We’re currently investigating an issue that prevented some customers from updating their payment details. The root cause has been identified, and a fix is being implemented.
Started May 11, 2026 — Resolved May 11, 2026
May 11, 16:02 EDT Resolved - This incident has been resolved. May 11, 15:46 EDT Monitoring - A fix has been implemented and we are monitoring the results. May 11, 14:55 EDT Identified - We are experiencing an elevated level of errors and latency on the Suppression List API for some SparkPost customers. Please retry any 5xx error. Note: This issue does not impact SparkPost customers hosted in the EU.
Started May 9, 2026 — Resolved May 9, 2026
May 9, 18:17 EDT Resolved - This incident has been resolved. May 9, 18:05 EDT Monitoring - A fix has been implemented and we are monitoring the results. May 9, 17:50 EDT Identified - The issue has been identified and a fix is being implemented. May 9, 17:39 EDT Investigating - We are looking into why some messages are seeing delayed delivery.
Started May 8, 2026 — Resolved May 8, 2026
May 8, 07:31 EDT Resolved - This incident has been resolved. May 7, 06:49 EDT Monitoring - A fix has been implemented and we are monitoring the results. May 7, 05:31 EDT Investigating - We are currently investigating this issue.
Pros and cons
Resend
Sparkpost
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
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
- Newer and less battle-tested compared to incumbents like Mailgun or SendGrid
- Fewer enterprise features than established providers
- Limited marketing email capabilities
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
Frequently asked questions
What is the difference between Resend and Sparkpost?
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.
Which is cheaper, Resend or Sparkpost?
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.
Which is faster, Resend or Sparkpost?
Based on real-world data from Knock, Resend has a median API response time (p50) of 97ms compared to 281ms for Sparkpost.
Which is more reliable, Resend or Sparkpost?
From April 14th to July 13th, Resend showed an error rate of 0.01% 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.
Which is more popular, Resend or Sparkpost?
On the Knock platform, Resend handled 10M–25M messages from April 14th to July 13th compared to <1M for Sparkpost. Resend volume has remained stable, while Sparkpost is trending upward.
Can I use both Resend and Sparkpost together?
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.
What are the main pros and cons of Resend vs Sparkpost?
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.
Use either provider with Knock
Knock enables you to integrate Resend, Sparkpost, or any combination of email providers into a single notification workflow. Manage templates, orchestrate cross-channel delivery, and switch providers without changing your code.