The SEO Framework vs Slim SEO: the two lightest plugins, head to head
Both are excellent, and they won our benchmark between them. The SEO Framework is the lighter on the server (+8.0 ms, 0 queries, 8 hooks) and in the editor. Slim SEO has the smaller footprint on disk and in the page (a 1.4 MB package and +1,649 head bytes) and the fuller sitemap. Pick on sitemap and social needs, not on speed.
The SEO Framework won or shared seven of sixteen categories in our seven-plugin benchmark, Slim SEO five. We build Hydrogen SEO, which placed behind both on cost.
The numbers
| Measured | The SEO Framework 5.1.4 | Slim SEO 4.10.1 |
|---|---|---|
| Front-end PHP time added | +8 ms | +10 ms |
| Peak memory added | +2 MB | +2 MB |
| Database queries added | +0 | +2 |
| Hooks registered | +8 | +51 |
<head> bytes added | +3,821 | +1,649 |
| Meta description by default | Yes | Yes |
| JSON-LD types printed | 9 | 10 |
| Open Graph / X tags | 10 / 5 | 11 / 2 |
| Sitemap URLs listed | 51 | 73 |
| Sitemap image entries | 0 | 40 |
lastmod coverage | 51 / 51 | 50 / 73 |
| Custom database tables | 0 | 0 |
| Autoloaded options added | +4.2 KB | -0.2 KB |
| Plugin package size | 2.9 MB | 1.4 MB |
| Block editor assets | 25 files, 77.6 KB | 14 files, 187.7 KB |
| After deactivation | Releases everything (exact baseline) | Releases everything |
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. Bold marks the better number in each row. Full method: how we tested.
What the numbers mean
On the server, the difference is small. The SEO Framework added +8.0 ms against Slim SEO's +10.0 ms, which is within what we would call a close result given timing varied about 10% between runs. Both added +2.0 MB of memory. The SEO Framework added no queries and 8 hooks; Slim SEO added 2 queries and 51 hooks. Neither creates tables.
Slim SEO wins the footprint rows. Its package is 1.4 MB against 2.9 MB, its <head> grew by 1,649 bytes against 3,821, and its autoloaded options came out fractionally below baseline where The SEO Framework's grew by 4.2 KB. The SEO Framework wins the editor: 77.6 KB of assets against 187.7 KB. Both left essentially nothing behind on deactivation.
Output is where the choice gets made. Slim SEO's sitemap listed 73 URLs including taxonomy archives, with all 40 featured images. The SEO Framework's is a flat file with 51 URLs, posts and pages only, and no images. But The SEO Framework stamped lastmod on every URL, while Slim SEO left 23 of 73 unstamped. Schema: Slim SEO printed 10 JSON-LD types in 3,828 bytes, The SEO Framework 9 types in 1,881. Social: Slim SEO printed 11 Open Graph but only 2 X tags; The SEO Framework printed 10 and 5. Both generate meta descriptions.
The admin philosophies differ too. Slim SEO added no admin menu items at all and has almost no configuration surface. The SEO Framework adds two menus and a settings page built around automatic defaults. Neither has AI features.
Choose The SEO Framework if
- You want zero extra queries and the fewest hooks we measured.
- You want the lightest editor (77.6 KB).
- You want
lastmodon every sitemap URL and fuller X tags. - You want a settings page, even a quiet one.
Choose Slim SEO if
- You want taxonomy archives and featured images in the sitemap.
- You want the smallest package and head growth in the field.
- You want a plugin that adds no admin menus.
- You do not depend on X card output.
Switching between them
Slim SEO includes a migration tool that can import from The SEO Framework among others; check its documentation for current coverage. For moving to The SEO Framework, check its documentation for migration options. Both plugins keep configuration light, so the work is mostly verifying per-post titles, descriptions and redirects on key pages. Hydrogen SEO also imports from both if you later want AI features; see switch from another SEO plugin.
Common questions
Which is faster, The SEO Framework or Slim SEO?
The SEO Framework, narrowly: +8.0 ms and 0 queries against +10.0 ms and 2 queries. Both added +2.0 MB of memory. The timing gap is small enough that you are unlikely to notice it.
Which has the better sitemap?
Slim SEO includes archives and featured images (73 URLs, 40 images). The SEO Framework's flat sitemap has 51 URLs and no images, but stamps lastmod on every URL.
Do either have AI features?
No. Both focus on low overhead. If you want AI features, Hydrogen SEO, Rank Math and others offer them at a higher cost.