Hydrogen SEO alternatives: six plugins, measured by the team that builds it
We build Hydrogen SEO, and our own benchmark says two plugins are lighter: The SEO Framework (+8.0 ms, 0 queries) and Slim SEO (+10.0 ms) against Hydrogen SEO's +12.9 ms and 1 query. If you want the lowest cost and do not need AI features, choose one of them. If you want maturity and the fullest output, Yoast is the established answer.
Every figure comes from our seven-plugin benchmark, run on one WordPress 7.1 install with each plugin active alone at defaults. We ranked the alternatives below by how well they serve someone leaving Hydrogen SEO, not by how well they flatter it.
Why people look for an alternative
These are the honest reasons to look past Hydrogen SEO, from the data and from what we know about it:
- It is Beta. It is the newest plugin here, with none of the years of field testing the others have. In an earlier version it shipped with no canonical tag at all, a bug our first benchmark exposed and a later version fixed.
- It is not the lightest. It placed third on PHP time and memory. Its +4.5 MB of memory is more than double The SEO Framework's and Slim SEO's, because it loads all modules on every request, which is the largest fix still outstanding.
- Its editor is heavier than the minimal plugins. 700.4 KB in 2 files, because the editor UI is a React bundle. That is far lighter than Yoast, All in One SEO or Rank Math, and far heavier than The SEO Framework (77.6 KB).
- AI needs an account. Every non-AI feature works without one, but AI writing tools and the agent require a free hydrogenseo.com account and use credits.
Reasons to stay: it added one query, created no custom tables in the benchmarked version (0.0.31 has one for link counts and a second if the 404 Monitor is in use), left almost nothing autoloading on deactivation, printed 10 schema types in 2,071 bytes (the most efficient graph measured), and was the only plugin whose sitemap had both featured images and lastmod on every URL. It is also the only plugin here with an agent that takes plain-language jobs, plus a hydrogenseo.com dashboard with site audits and tools. If those matter to you, it is doing what it is meant to do.
The SEO Framework
Measured on 5.1.4: +8 ms front-end, +0 queries, 9 JSON-LD types, 0 custom tables
The lightest plugin we measured: +8.0 ms, zero queries, 8 hooks, 77.6 KB in the editor, and an exact baseline on deactivation. It prints 9 schema types and the same social tags as Hydrogen SEO. You give up archives and images in the sitemap, and any AI features. See Hydrogen SEO vs The SEO Framework.
Slim SEO
Measured on 4.10.1: +10 ms front-end, +2 queries, 10 JSON-LD types, 0 custom tables
Lighter than Hydrogen SEO on memory, package size (1.4 MB) and head growth, with 10 schema types and a sitemap that includes archives and images. It adds no admin menus and has very little to configure. It printed only 2 X tags and left 23 sitemap URLs without
lastmod. See Hydrogen SEO vs Slim SEO.Yoast SEO
Measured on 28.4: +39 ms front-end, +3 queries, 12 JSON-LD types, 6 custom tables
The choice if Beta status is the problem. Yoast has the longest track record, the richest schema (12 types) and the most complete sitemap (75 URLs with images). It costs about three times the PHP time, creates six tables and loads 4,160 KB into the editor, and prints no meta description by default. See Hydrogen SEO vs Yoast SEO.
SEOPress
Measured on 10.2: +24.5 ms front-end, +1 queries, 0 JSON-LD types, 1 custom tables
A mature, restrained plugin with one query and a lighter editor than Hydrogen SEO (217 KB). It suits agencies with many sites. Its free version printed no schema at defaults, and it released none of its autoloaded options on deactivation. See Hydrogen SEO vs SEOPress.
Rank Math
Measured on 1.0.278: +36.1 ms front-end, +16 queries, 6 JSON-LD types, 6 custom tables
Mature, highly configurable, with the fullest social tags we measured and its own AI features. It costs more (+36.1 ms, 16 queries, six tables) and leaves images out of its sitemap by default. See Hydrogen SEO vs Rank Math.
All in One SEO
Measured on 5.0.1.1: +53.5 ms front-end, +22 queries, 8 JSON-LD types, 9 custom tables
Mature and approachable, with a guided setup and a large product family. It was the heaviest plugin in every cost category we measured, including nine tables and a 511 KB dashboard. See Hydrogen SEO vs All in One SEO.
All seven, measured
| Measured | Hydrogen SEO 0.0.18 | The SEO Framework 5.1.4 | Slim SEO 4.10.1 | Yoast SEO 28.4 | SEOPress 10.2 | Rank Math 1.0.278 | All in One SEO 5.0.1.1 |
|---|---|---|---|---|---|---|---|
| Front-end PHP time added | +12.9 ms | +8 ms | +10 ms | +39 ms | +24.5 ms | +36.1 ms | +53.5 ms |
| Peak memory added | +4.5 MB | +2 MB | +2 MB | +10.5 MB | +6.5 MB | +8.5 MB | +14.5 MB |
| Database queries added | +1 | +0 | +2 | +3 | +1 | +16 | +22 |
| Hooks registered | +22 | +8 | +51 | +187 | +114 | +155 | +100 |
<head> bytes added | +4,259 | +3,821 | +1,649 | +5,656 | +2,380 | +4,965 | +6,668 |
| Meta description by default | Yes | Yes | Yes | No | Yes | Yes | Yes |
| JSON-LD types printed | 10 | 9 | 10 | 12 | 0 | 6 | 8 |
| Open Graph / X tags | 10 / 5 | 10 / 5 | 11 / 2 | 10 / 5 | 10 / 6 | 11 / 8 | 6 / 3 |
| Sitemap URLs listed | 72 | 51 | 73 | 75 | 58 | 59 | 73 |
| Sitemap image entries | 40 | 0 | 40 | 40 | 40 | 0 | 0 |
lastmod coverage | 72 / 72 | 51 / 51 | 50 / 73 | 74 / 75 | 50 / 58 | 59 / 59 | 73 / 73 |
| Custom database tables | 1 (2 with the 404 Monitor on) | 0 | 0 | 6 | 1 | 6 | 9 |
| Autoloaded options added | +0.4 KB | +4.2 KB | -0.2 KB | +13.6 KB | +3.6 KB | +11.6 KB | +14.6 KB |
| Plugin package size | 4.6 MB | 2.9 MB | 1.4 MB | 21 MB | 11.7 MB | 15.1 MB | 24.4 MB |
| Block editor assets | 2 files, 700.4 KB | 25 files, 77.6 KB | 14 files, 187.7 KB | 48 files, 4,160 KB | 17 files, 217 KB | 24 files, 1,792 KB | 130 files, 3,543 KB |
| After deactivation | +0.2 KB left autoloading | Releases everything (exact baseline) | Releases everything | +2.6 KB left autoloading, 6 tables remain | No reduction at all | +11.0 KB still autoloading | 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 | Hydrogen SEO 0.0.31 | The SEO Framework 5.2.1 | Slim SEO 4.11.5 | Yoast SEO 28.8 | SEOPress 10.4 | Rank Math 1.0.282 | All in One SEO 5.0.5 |
|---|---|---|---|---|---|---|---|
| Search engine verification codes | Free | Free | — | Free | Free | Free | Free |
| IndexNow instant indexing | Free | — | — | Paid | Free | Free | Paid |
| Redirect manager | Free | — | Free | Paid | Paid | Free | Paid |
| 404 monitor | Free | No | 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 | — | — | Paid | — | Free | 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 | — | — | Free | Paid | 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
Is Hydrogen SEO the lightest SEO plugin?
No. In our own benchmark The SEO Framework (+8.0 ms, 0 queries) and Slim SEO (+10.0 ms) were lighter than Hydrogen SEO (+12.9 ms, 1 query).
What does Hydrogen SEO do that the alternatives do not?
It includes an AI agent that takes plain-language SEO jobs through registered abilities, with confirmations before destructive changes. It also pairs with a hydrogenseo.com dashboard. AI features need a free account.
Can I leave Hydrogen SEO easily?
In our test it left 0.2 KB of autoloaded options after deactivation. From 0.0.30 it keeps link counts in one table of its own, and the 404 Monitor adds a second if you switch it on; deleting the plugin removes both. Check your destination plugin's importer for supported sources before switching.