Hydrogen SEO vs Rank Math: Speed, Schema, AI and Price, Measured

On the same WordPress install, Hydrogen SEO adds +12.9 ms of PHP time, +1 database query and 0 custom tables to a page; Rank Math adds +36.1 ms, +16 queries and 6 tables. Rank Math prints the most complete social tags of any plugin we have tested (11 Open Graph and 8 X tags); Hydrogen SEO prints a larger schema graph in fewer bytes (10 JSON-LD types in 2,071 bytes against Rank Math's 6 in 2,665). Rank Math is the mature, feature-dense choice with years of real-world use behind it. Hydrogen SEO is lighter, still in Beta, and the only one of the two with a plain-language SEO agent.

A disclosure before anything else: Sheesh Labs builds Hydrogen SEO, so read this as a builder's view rather than a neutral review. Every number below comes from our seven-plugin WordPress SEO benchmark, re-run on 8 September 2026, where Rank Math and Hydrogen SEO ran one at a time on identical hardware. Hydrogen SEO did not win that benchmark overall — The SEO Framework and Slim SEO beat both plugins on cost — and Rank Math has an install history we cannot match yet. We are not going to pretend otherwise.

Is Hydrogen SEO faster than Rank Math?

Yes, on every cost metric we measured, and by a wide margin on queries. The rig was WordPress 7.1, PHP 8.2.27, MySQL 8.0.35, the Twenty Twenty-Five theme, 40 posts and 8 pages, with the database restored between plugins and the median of 13 measured requests taken after 6 warm-ups. Everything is the change from a baseline WordPress with no SEO plugin active.

Three of those rows deserve a sentence each.

Queries. Rank Math's +16 is new. At 1.0.277.2 its query count wandered between 41 and 50 across runs; at 1.0.278 it settled at a stable +16, which was the largest regression from any plugin update we saw during the whole benchmark. Hydrogen SEO's +1 is also new: version 0.0.14 added +7, because it read its own settings one key at a time, and the fix in 0.0.15 primed them in one query. On a site that has saved its settings once, it drops to +0.

Autoloaded options. These are read on every request, admin and front end, whether or not the page uses them. Rank Math adds 11.6 KB; Hydrogen SEO adds 0.4 KB. Deactivating Rank Math leaves 60.8 KB autoloading against a 49.8 KB baseline, so 11.0 KB of it stays behind. Hydrogen SEO leaves 50.0 KB.

Tables. Rank Math creates six custom tables, four of them belonging to the Action Scheduler library it bundles. They survive deactivation. Hydrogen SEO creates none, by design: everything lives in standard WordPress options and post meta.

If speed is the only thing you care about, be aware that both plugins lose to two others. The SEO Framework adds +8.0 ms and +0 queries; Slim SEO adds +10.0 ms and +2 queries. Our sister site's fastest WordPress SEO plugin round-up walks through that ranking without our name at the top.

What does each plugin print on a post?

Cost only matters against output, so here is what actually landed in the page on a standard post at each plugin's defaults.

Rank Math wins social tags outright, and not just against us: 11 Open Graph plus 8 X tags was the most complete social output of all seven plugins. If share cards are your priority, that is a real point in its favour.

Hydrogen SEO won the benchmark's "most efficient schema" category: ten structured data types in 2,071 bytes, the smallest graph of any plugin that printed a full one. Rank Math's six types are complete and valid; they simply cover less of the page in more bytes.

The sitemap gap is a defaults finding, not a capability finding. Rank Math ships with include_images on but include_featured_image off, so on a site whose images are featured images its sitemap carries none until you change that setting. It also omits tag and author archives by default, which is why it lists 59 URLs to Hydrogen SEO's 72. Both plugins stamp every URL with a lastmod. Our XML sitemap guide covers what should and should not be in there.

One row in that table used to be ours to lose. Hydrogen SEO 0.0.14 printed no canonical tag at all, on any page, and suppressed the one WordPress core would have printed. Bare WordPress did better than our plugin. It was fixed in 0.0.15 with one central canonical output for every context, and we left the account of it in the benchmark rather than deleting it once the row turned green. Sheesh Labs wrote up the whole episode in why we published a benchmark we lost.

Why did Rank Math need a configuration step?

Because out of the box it prints nothing. Rank Math gates its front-end output behind registration: until you either connect an account or click Skip, no titles, meta or schema reach the page. We set the same two options its own Skip button sets so the plugin would behave the way a real installation does after setup. Without that step it would have looked deceptively light in every table above, adding almost no cost because it was doing almost no work.

Hydrogen SEO takes the opposite position. Every non-AI feature works with no account and no key: titles and meta, schema, sitemaps, robots.txt, the llms.txt editor, redirects, audits and the health score. A free hydrogenseo.com account is only needed when you want the AI features, and if your AI credits run out only AI generation pauses. Nothing else breaks.

Which is lighter inside wp-admin?

The cost you feel day to day is in the editor, not on the front end (where all seven plugins, Rank Math and Hydrogen SEO included, added zero files and zero inline JavaScript).

Rank Math renders a 154.0 KB dashboard and loads 24 of its own files totalling 1,792 KB into the block editor. Hydrogen SEO renders a 131.2 KB dashboard and loads 2 files totalling 700.4 KB. Bare WordPress was 129.8 KB.

We would rather explain our editor number than spin it. Two files but 700 KB, because Hydrogen SEO's editor UI is a React application shipped as one bundle. That is less than half of Rank Math's editor weight, and it is still nine times heavier than The SEO Framework's 77.6 KB. It is the real price of a modern dashboard, and we state it.

How do the AI features differ?

Rank Math invested in AI early and its interface is dense with options, which suits people who enjoy configuring things. We do not have measured numbers for its AI layer and will not invent any; its own site describes it best.

Hydrogen SEO's AI comes in two layers. The first is writing help where you already work: six fields in the editor's SEO sheet carry AI buttons (SEO title, meta description, Open Graph title and description, X title and description), each returning several suggestions with character counts. Add AI image alt text, single or bulk across the media library, content generation and rewriting, featured image generation and AI-assisted schema.

The second layer is Hydrogen AI, an agent you brief in plain language: "write meta descriptions for every post missing one", "add FAQ schema to this page", "find and fix broken internal links". It works through the plugin's own registered abilities on the WordPress Abilities API (87 in the free plugin, 90 with Pro), asks before anything it cannot undo, shows every change, can be stopped mid-job, and runs on a revocable WordPress application password. You can set it to confirm destructive changes only, confirm every write, or run read-only.

None of the established plugins, Rank Math included, offered plain-language agent delegation as of our comparison. Whether you want that is a fair question; our sister site RankWave AI has a useful essay on what changes when an AI executes SEO work rather than suggesting it.

What do they cost?

Hydrogen SEO's plugin is free, and the pricing is entirely about AI credits and sites, never features. Free is $0 forever with 500 AI credits on signup. Pro is $99 a year (was $149) or $399 lifetime, with 20,000 credits a year and the Pro plugin with automatic updates. Max is $179 a year (was $249) or $799 lifetime, with 50,000 credits a year. One credit is one single-URL audit; image generation costs 3, alt text 1, content 2. Sheesh Labs breaks the model down in Hydrogen SEO pricing explained.

Rank Math's free tier is unusually generous, and it has paid tiers. We are not going to quote its prices here because they change and belong on its own site. Compare the two on their current pages, not on a blog post.

How do I move from Rank Math to Hydrogen SEO?

Without starting over. Tools → Import SEO Data in Hydrogen SEO detects Rank Math and Rank Math PRO and brings across title and description templates, robots rules, homepage SEO, social defaults, knowledge graph settings, your robots.txt, every post and term's own SEO fields, focus keywords, canonicals, schema types and redirect rules. Rank Math's smart tags are translated into Hydrogen SEO's template variables rather than copied as dead text.

The safety rails matter more than the checklist. You run a dry run first and see the current value, the value that would be written and the reason for every setting. Real imports run in batches, can be paused and resumed, and every run stays in history with an Undo that restores the settings snapshot and removes imported fields you have not edited since. Nothing is deleted from Rank Math; deactivating it is a separate, reversible step that is on by default because two active SEO plugins print duplicate tags. From the command line:

wp hydrogen-seo migrate run rank-math --dry-run
wp hydrogen-seo migrate run rank-math

The import module shipped in 0.0.19 for Rank Math, Yoast and SureRank, and 0.0.20 extended it to All in One SEO, The SEO Framework, Slim SEO and SEOPress. The full procedure is in switch from another SEO plugin, and Sheesh Labs has a walk-through of a real switch in import, dry run, undo.

Who should pick which?

• Pick Rank Math if you want the most switches per dollar, the most complete social tags, years of production history, and you enjoy configuring things. Plan for +16 queries and six tables, and check the featured-image sitemap setting.
• Pick Hydrogen SEO if you want a plugin that adds one query and no tables, prints an efficient schema graph, works fully with no account, and you want an AI agent you can hand jobs to. Accept that it is Beta software and test it on staging first, as our installation guide says.
• Pick neither if raw cost is everything: The SEO Framework and Slim SEO are lighter than both, and we say so in the benchmark.
• Stay where you are if Rank Math is working for you and nothing above names a problem you actually have. Switching has a cost, even with a dry run and an undo.

Frequently asked questions

Is Hydrogen SEO faster than Rank Math?

On our benchmark rig, yes: Hydrogen SEO 0.0.18 added +12.9 ms of PHP time and +1 query per request, Rank Math 1.0.278 added +36.1 ms and +16 queries. Both plugins are slower than The SEO Framework and Slim SEO. Treat the millisecond figures as relative costs, not as predictions for your server.

Does Rank Math print more schema than Hydrogen SEO?

No. At defaults on a standard post Rank Math printed 6 JSON-LD types in 2,665 bytes; Hydrogen SEO printed 10 types in 2,071 bytes. Rank Math did print more social tags: 11 Open Graph and 8 X tags against Hydrogen SEO's 10 and 5.

Can I import my Rank Math settings into Hydrogen SEO?

Yes. Tools → Import SEO Data detects Rank Math and Rank Math PRO, previews every change in a dry run, imports in batches with pause and resume, and keeps an Undo in history. Nothing is deleted from Rank Math. WP-CLI: wp hydrogen-seo migrate run rank-math --dry-run.

Does Hydrogen SEO need an account like Rank Math needs registration?

No. Every non-AI feature works with no account and no key. Rank Math gates its front-end output behind registration or its Skip button. Hydrogen SEO only asks for a free hydrogenseo.com account when you use AI features or the Hydrogen AI agent.

Is Hydrogen SEO production-ready?

It is Beta software at version 0.0.20. The core output is server-rendered standard markup and it has been measured on the same rig as six established plugins, but as with any beta, test on staging first. Who builds it and how fixes ship is covered in who builds Hydrogen SEO.