How Site Mailer – SMTP Replacement, Email API Deliverability & Email Log Affects Your WordPress Speed
How is this scored?
Our Benchmark Methodology
Every speed score on MakeWPFast is based on real performance measurements, not estimates. We install each plugin on a clean WordPress 6.9 setup (PHP 8.3, MariaDB, GeneratePress theme) and measure the difference in three metrics:
TTFB (Time To First Byte) — how many milliseconds the plugin adds to server response time. This is the most important factor (50% of the score) because it directly affects every page load.
Memory usage — how much additional PHP memory the plugin consumes per request (30% of score). High memory usage can cause crashes on shared hosting.
Database queries — how many extra SQL queries the plugin runs per page load (20% of score). More queries mean more database work on every request.
| Grade | What it means |
|---|---|
| A / A- | Negligible impact. Safe to install on any hosting. |
| B+ / B / B- | Light impact. Adds some overhead but manageable on most setups. |
| C+ / C / C- | Moderate impact. May noticeably slow down budget hosting. |
| D+ / D | Heavy impact. Will affect page load times. Consider alternatives. |
| F | Severe impact. Significant resource usage that hurts performance. |
Plugins marked "Not Yet Tested" have not been benchmarked yet. We do not estimate or guess scores — if there is no measured data, there is no grade.
Note: Benchmarks measure a plugin in isolation on a clean install. Real-world impact varies based on your hosting, other plugins, and how the plugin is configured.
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Performance Analysis
Performance Impact
Site Mailer – SMTP Replacement, Email API Deliverability & Email Log receives an estimated speed score of C-. Our real benchmark tests measured the following impact when activating this plugin:
- TTFB impact: +-5 ms
- Memory impact: +0.0 MB
- Additional DB queries: +5
Overall activation impact: low. This plugin adds minimal overhead to your WordPress site.
Maintenance Status
Last updated: 2026-01-28. Requires PHP 7.4+. Trusted by 200K+ active installations.
Benchmark data measured in an isolated Docker environment (WordPress 6.8, PHP 8.3, GeneratePress). See our full methodology.
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Alternatives to Site Mailer – SMTP Replacement, Email API Deliverability & Email Log
| Plugin | Speed Score | Active Installs |
|---|---|---|
| MonsterInsights – Google Analytics Dashboard for WordPress (Website Stats Made Easy) | A | 2M+ |
| GTM4WP – A Google Tag Manager (GTM) plugin for WordPress | A | 700K+ |
| Header Footer Code Manager | A | 600K+ |
Frequently Asked Questions
Does Site Mailer – SMTP Replacement, Email API Deliverability & Email Log slow down WordPress?
Is Site Mailer – SMTP Replacement, Email API Deliverability & Email Log still maintained?
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