The best lightweight WordPress SEO plugin, measured on one site
The SEO Framework is the lightest WordPress SEO plugin we measured: +8.0 ms of PHP time, +2.0 MB of memory and zero extra database queries per request, with only 8 hooks registered. Slim SEO is a close second at +10.0 ms and ships the smallest package (1.4 MB). Both still print a meta description, a canonical and a 9 or 10-type schema graph, so they are light without being empty.
The numbers come from our seven-plugin benchmark: WordPress 7.1, one plugin active at a time, database restored between runs, free versions at defaults. We build Hydrogen SEO, which placed third, and we ranked it there.
How we ranked them
Front-end weight does not separate these plugins. All seven added 0 scripts, 0 stylesheets and 0 bytes of inline JavaScript to a public page, so "lightweight" has to mean what a plugin costs on the server and in wp-admin. Three measurements decide it:
- PHP time and memory per request, the direct cost of every uncached page view. Timings moved about ±10% between runs, so read them as relative.
- Database queries and autoloaded options, which were byte-identical across both runs. Autoloaded options are read on every request, admin and front end.
- Block editor assets, the weight you feel every time you open a post.
Where two plugins are close, the deterministic metrics break the tie.
The SEO Framework
Measured on 5.1.4: +8 ms front-end, +0 queries, 9 JSON-LD types, 0 custom tables
Lowest PHP time (+8.0 ms), joint-lowest memory (+2.0 MB), the only plugin with zero extra queries, and 8 hooks against Yoast's 187. In the editor it loads 77.6 KB of its own assets, the lightest figure we recorded, and deactivating it restored autoloaded options to the exact baseline. The trade is a minimal flat sitemap: 51 URLs, posts and pages only, no images. See The SEO Framework alternatives.
Slim SEO
Measured on 4.10.1: +10 ms front-end, +2 queries, 10 JSON-LD types, 0 custom tables
+10.0 ms and +2.0 MB, with the smallest
<head>growth (+1,649 bytes), the smallest package (1.4 MB) and autoloaded options slightly below baseline (-0.2 KB). It adds no admin menus at all. It loses first place on queries (+2), hooks (51) and editor weight (187.7 KB), and its output is thinner: 2 X tags and 23 of 73 sitemap URLs withoutlastmod. See The SEO Framework vs Slim SEO.Hydrogen SEO
Measured on 0.0.18: +12.9 ms front-end, +1 queries, 10 JSON-LD types, custom tables in 0.0.31: 1 (2 with the 404 Monitor on)
Ours. +12.9 ms, +4.5 MB, 1 query (0 once settings have been saved), 0.4 KB of autoloaded options and no custom tables in the benchmarked version, 0.0.18. That last figure has aged: 0.0.31 stores link counts in a table, and the optional 404 Monitor brings a second. Memory is its weak spot: it loads all of its modules on every request, including admin-only ones. Its editor loads 2 files but 700.4 KB, because the editor UI is one React bundle, so it sits well behind the top two in wp-admin. It is Beta software.
SEOPress
Measured on 10.2: +24.5 ms front-end, +1 queries, 0 JSON-LD types, 1 custom tables
The lightest of the long-established, feature-rich plugins: +24.5 ms, +6.5 MB, 1 query and only 217 KB in the editor. It creates one custom table, and its 3.6 KB of autoloaded options did not shrink at all when we deactivated it. Its small
<head>growth (+2,380 bytes) partly reflects that the free version printed no JSON-LD.Rank Math
Measured on 1.0.278: +36.1 ms front-end, +16 queries, 6 JSON-LD types, 6 custom tables
+36.1 ms, +8.5 MB and +16 queries per request, with six custom tables and 11.6 KB of autoloaded options, 11.0 KB of which kept loading after deactivation. Its editor is 24 files and 1,792 KB. It is slightly lighter than Yoast on PHP time and much lighter in the editor, but heavier on queries.
Yoast SEO
Measured on 28.4: +39 ms front-end, +3 queries, 12 JSON-LD types, 6 custom tables
+39.0 ms, +10.5 MB and the largest hook surface in the field (187). It holds queries to +3 because its six indexables tables pre-compute SEO data, but it loads 4,160 KB of its own assets into the block editor, the heaviest single figure we recorded, and adds 13.6 KB of autoloaded options. See Yoast SEO alternatives.
All in One SEO
Measured on 5.0.1.1: +53.5 ms front-end, +22 queries, 8 JSON-LD types, 9 custom tables
Last on every server cost: +53.5 ms, +14.5 MB, +22 queries, the largest
<head>growth (+6,668 bytes), nine custom tables and a 24.4 MB package. Its dashboard measured 511 KB, about four times bare WordPress, and deactivating it released none of its 14.6 KB of autoloaded options.
What "lightweight" does and doesn't buy you
Lightweight buys you headroom on uncached requests: logged-in users, wp-admin, search results, cart pages and cron. On a page served from a full-page cache, PHP never runs, and the gap between +8 ms and +54 ms disappears for that visitor. If most of your traffic is cached, editor weight and autoloaded options are the costs you will actually notice.
It does not buy you output. The two lightest plugins make real trade-offs: The SEO Framework submits no taxonomy archives or images in its sitemap, and Slim SEO has almost nothing to configure. If you need a full sitemap with images and lastmod on every URL, a slightly heavier plugin may be the better deal; see the best SEO plugin for sitemaps.
And our milliseconds come from a single-threaded test server, not your host. The ratios transfer; the absolute numbers do not. To measure your own site, follow the benchmark method.
All seven, measured
| Measured | The SEO Framework 5.1.4 | Slim SEO 4.10.1 | Hydrogen SEO 0.0.18 | SEOPress 10.2 | Rank Math 1.0.278 | Yoast SEO 28.4 | All in One SEO 5.0.1.1 |
|---|---|---|---|---|---|---|---|
| Front-end PHP time added | +8 ms | +10 ms | +12.9 ms | +24.5 ms | +36.1 ms | +39 ms | +53.5 ms |
| Peak memory added | +2 MB | +2 MB | +4.5 MB | +6.5 MB | +8.5 MB | +10.5 MB | +14.5 MB |
| Database queries added | +0 | +2 | +1 | +1 | +16 | +3 | +22 |
| Hooks registered | +8 | +51 | +22 | +114 | +155 | +187 | +100 |
<head> bytes added | +3,821 | +1,649 | +4,259 | +2,380 | +4,965 | +5,656 | +6,668 |
| Meta description by default | Yes | Yes | Yes | Yes | Yes | No | Yes |
| JSON-LD types printed | 9 | 10 | 10 | 0 | 6 | 12 | 8 |
| Open Graph / X tags | 10 / 5 | 11 / 2 | 10 / 5 | 10 / 6 | 11 / 8 | 10 / 5 | 6 / 3 |
| Sitemap URLs listed | 51 | 73 | 72 | 58 | 59 | 75 | 73 |
| Sitemap image entries | 0 | 40 | 40 | 40 | 0 | 40 | 0 |
lastmod coverage | 51 / 51 | 50 / 73 | 72 / 72 | 50 / 58 | 59 / 59 | 74 / 75 | 73 / 73 |
| Custom database tables | 0 | 0 | 1 (2 with the 404 Monitor on) | 1 | 6 | 6 | 9 |
| Autoloaded options added | +4.2 KB | -0.2 KB | +0.4 KB | +3.6 KB | +11.6 KB | +13.6 KB | +14.6 KB |
| Plugin package size | 2.9 MB | 1.4 MB | 4.6 MB | 11.7 MB | 15.1 MB | 21 MB | 24.4 MB |
| Block editor assets | 25 files, 77.6 KB | 14 files, 187.7 KB | 2 files, 700.4 KB | 17 files, 217 KB | 24 files, 1,792 KB | 48 files, 4,160 KB | 130 files, 3,543 KB |
| After deactivation | Releases everything (exact baseline) | Releases everything | +0.2 KB left autoloading | No reduction at all | +11.0 KB still autoloading | +2.6 KB left autoloading, 6 tables remain | No reduction: 14.5 KB still autoloading |
Measured on one WordPress 7.1 install (PHP 8.2, MySQL 8.0, Twenty Twenty-Five, 40 posts), each plugin alone with default settings, against a no-plugin baseline. Each column heading names the version that was measured. Bold marks the better number in each row. Full method: how we tested.
Hydrogen SEO's figures were measured on 0.0.18 and have not been re-run on later versions. The custom tables row is the exception: it is counted from the 0.0.31 source. A default install has one table, for the internal link counter. Switching on the 404 Monitor, which is off by default, creates a second for its log. Deleting the plugin removes both.
Features: free, paid or not offered
| Feature | The SEO Framework 5.2.1 | Slim SEO 4.11.5 | Hydrogen SEO 0.0.31 | SEOPress 10.4 | Rank Math 1.0.282 | Yoast SEO 28.8 | All in One SEO 5.0.5 |
|---|---|---|---|---|---|---|---|
| Search engine verification codes | Free | — | Free | Free | Free | Free | Free |
| IndexNow instant indexing | — | — | Free | Free | Free | Paid | Paid |
| Redirect manager | — | Free | Free | Paid | Free | Paid | Paid |
| 404 monitor | No | Free | Free | Paid | Free | — | Paid |
| SEO column on the Posts screen | Free | Free | Free | Free | Free | Free | Free |
| SEO fields in Quick Edit | Free | Free | Free | Free | Paid | — | — |
| Attachment page redirects | — | Free | Free | Free | Free | Free | Free |
| Author and date archive controls | Free | — | Free | Free | Free | Free | Free |
| RSS feed text | — | — | Free | — | Free | Free | Free |
| max-snippet and preview controls | Free | — | Free | — | Free | — | Free |
| Primary category | Free | Free | Free | Free | Free | Free | Paid |
| Internal link counts on the Posts screen | — | — | Free | Free | Free | Free | — |
| Automatic image alt attributes | — | Free | Free | Free | Free | — | Paid |
| Table of contents block | — | — | Free | — | Free | Paid | Free |
| HTML sitemap | — | — | Free | Free | Free | — | Free |
| Pillar or cornerstone content flag | — | — | Free | — | Free | Free | Paid |
| Crawl cleanup switches | — | — | Free | Free | — | Free | — |
| Video sitemap | — | — | Free | Paid | Paid | Paid | Paid |
| Google News sitemap | — | Free | Free | Paid | Paid | Paid | Paid |
| llms.txt | — | — | Free | Paid | Free | Free | Free |
This table is not benchmark data. It is based on each plugin's WordPress.org listing, the code of its free version there, and its official documentation and pricing pages, checked on 12 November 2026, for the version in each column heading. Free means the feature is in the plugin's own free version. Paid means it needs that plugin's paid version or a paid add-on. No means the plugin's listing says it does not offer it. A dash means we could not confirm it either way; it does not mean the feature is missing. A row says a feature exists, not how complete it is. Plugins change, so check the plugin's own site before relying on a cell. If a cell is wrong, tell us and we will correct it.
Common questions
What is the lightest WordPress SEO plugin?
The SEO Framework, in our benchmark: +8.0 ms of PHP time, +2.0 MB of memory and zero extra queries. Slim SEO was second at +10.0 ms and has the smallest package at 1.4 MB.
Do SEO plugins add JavaScript to the front end?
None of the seven we tested added any front-end script, stylesheet or inline JavaScript on a standard post. Their cost is server time, database work and wp-admin weight.
Is Slim SEO or The SEO Framework lighter?
It depends on the metric. The SEO Framework wins PHP time, queries, hooks and editor weight; Slim SEO wins head size, autoloaded options and package size. Both added +2.0 MB of memory.
Which SEO plugin is the heaviest?
All in One SEO lost every cost category it entered: +53.5 ms, +22 queries, nine custom tables and a 511 KB dashboard. Yoast had the heaviest editor at 4,160 KB.