Beta software. Hydrogen SEO is new. Every feature below works and is covered by automated tests, but it has not had the years of field testing the established SEO plugins have. Try it on a staging site first if that matters to you.
Hydrogen SEO is a lightweight, AI-powered SEO plugin for WordPress. It writes your meta titles and meta descriptions, generates schema markup, fills in image alt text, and audits your site for the on-page issues that hold rankings back — all from a fast, modern dashboard and directly inside the block editor.
It is built for how search works now. Alongside the metadata and structured data Google reads, it gives you an llms.txt editor and clean, machine-readable output, so the systems that answer questions from web content have something unambiguous to work from.
Hydrogen AI: an SEO agent inside your dashboard
Ask for what you want in plain language — “write meta descriptions for every post missing one”, “add FAQ schema to this page”, “find and fix broken internal links” — and Hydrogen AI does the work through the plugin’s own tools. It asks before anything it cannot undo, shows you every change it makes, and you can stop it at any point.
Hydrogen AI lives in two places: the plugin dashboard for site-wide work, and a tab in the editor’s SEO Settings sheet scoped to the post you are editing.
AI writing tools
- AI meta titles and meta descriptions — click the AI button beside the field, get several suggestions with character counts, pick one and it fills the field
- AI social titles and descriptions for Facebook / Open Graph and X (Twitter)
- AI image alt text for a single image or in bulk across your media library
- AI content generation and rewriting for SEO
- AI featured image generation
- AI-assisted schema (structured data) for your business details
On-page SEO essentials
- SEO titles and meta descriptions with template variables for posts, pages, custom post types, taxonomies and archives
- Schema markup (JSON-LD): Article, Product, FAQ, HowTo, Recipe, Course, Event, Local Business, Breadcrumbs and more
- XML sitemaps
- Robots meta controls per post, plus a built-in robots.txt editor
- Open Graph and X (Twitter) card previews, so you see the share card before you publish
- Google search result (SERP) preview as you type
- Redirection manager with 301 and 302 support
- One-click import from Rank Math, Yoast SEO, SureRank, All in One SEO, The SEO Framework, Slim SEO and SEOPress, with preview and undo
- Homepage SEO settings and canonical URLs
Built for AI search: answer engine optimization (AEO)
Answer engine optimization (AEO) is getting your content cited by assistants like ChatGPT, Perplexity and Google’s AI answers, not just ranked in a list of links. Hydrogen SEO gives you the on-site half of that:
- llms.txt editor — publish crawl and usage guidance for large language models, the emerging convention for AI answer engines
- Structured data and metadata written to be machine-readable, so your pages are unambiguous to anything parsing them
- Server-rendered output — nothing about your SEO depends on JavaScript running
- Clean XML sitemaps with images and accurate lastmod dates, so crawlers and answer engines see what changed and when
AI visibility monitoring — tracking where your brand is mentioned and cited across AI assistants — runs on the connected hydrogenseo.com account rather than inside the plugin.
Switching from another SEO plugin
Already using another SEO plugin? Hydrogen SEO imports your work so you do not start from scratch. Tools Import SEO Data detects Rank Math SEO (and Rank Math PRO), Yoast SEO (and Yoast SEO Premium), SureRank (and SureRank Business), All in One SEO (free and Pro), The SEO Framework, Slim SEO (and Slim SEO Pro) and SEOPress (and SEOPress PRO) and brings over:
- Title and meta description templates, separator and capitalization
- noindex / nofollow / noarchive rules per post type and taxonomy
- Homepage SEO, social defaults, Twitter handle, default share image and social profiles
- Organization / Person knowledge graph, website name and alternate name
- robots.txt content and sitemap options
- Every post, page, category and tag with its own SEO title, description, focus keyword, canonical URL, robots, social title / description / image and schema type
- Redirect rules, including Yoast Premium, SureRank Business, All in One SEO Pro, Slim SEO and SEOPress PRO redirects
Smart tags are translated to Hydrogen SEO variables, items that only followed the old plugin’s defaults keep following yours, anything you already customized in Hydrogen SEO is kept unless you choose to overwrite it, and a preview (dry run) shows every change before anything is written. Imports run in batches, can be paused and resumed, and every import can be undone from the history. Once it completes the old plugin is deactivated for you (optional), and nothing is deleted from it. WP-CLI: wp hydrogen-seo migrate run rank-math --dry-run.
Site audits and health checks
The dashboard scores your site across seven areas — crawlability, performance, mobile, security, content structure, schema markup and technical health — with a clear list of what to fix first. Site-wide audits find duplicate titles and descriptions, keyword cannibalisation, orphan pages, broken internal links and metadata that is too long or too short.
Fast and clean
- Modern React dashboard
- Heavy assets load on demand, so wp-admin stays quick
- No front-end JavaScript and no extra front-end requests — the SEO output is server-rendered markup
- Every screen is backed by the plugin’s own REST API
Free account for AI features
The AI features are powered by the Hydrogen SEO API. Create a free account at hydrogenseo.com, connect it from the plugin in one click, and you get free AI credits to start with.
Every non-AI SEO feature — titles, meta descriptions, schema, sitemaps, robots.txt, redirections, previews, audits — works with no account and no key.
Privacy
Hydrogen SEO adds no tracking, no analytics, no cookies and no front-end scripts. It does not phone home on a schedule. Nothing leaves your site until you use a feature that needs the Hydrogen SEO API.
Stored on your own site
- Your Hydrogen SEO API key, in the WordPress options table
- Your SEO settings, schema data, redirects and per-post metadata, in your own database
- The agent connection details when Hydrogen AI is connected: the service URL, a site identifier and a service key
- Nothing else. No visitor data, no personal data about your readers
Sent to the Hydrogen SEO API, only on your action
- The text or image you ask an AI feature to work with — a topic, the content to improve, an image URL for alt text, a prompt for image generation, or your business details for schema
- Your API key, to authorise and meter the request
- For Hydrogen AI: your instructions, plus the SEO data of the pages it is working on
- When you connect an account: your site URL, and the name and email you choose to give
- When you connect Hydrogen AI: your site URL, your WordPress username, the application password described above, your WordPress version, the plugin version and the environment type (production, staging or local)
Application password handling
The application password the plugin mints for Hydrogen AI is transmitted over HTTPS and stored encrypted at rest (AES-256-GCM) by the Hydrogen SEO service, alongside a non-reversible fingerprint that only lets the interface confirm which credential is on file. Plain HTTP is refused for anything but local development hosts. If registration fails, the credential just created is deleted immediately rather than left on your account. Disconnecting, or revoking it in Users Profile, ends that access.
The setup wizard
The wizard optionally asks for your name and email. If you fill them in and tick the consent checkbox, they are sent with your site URL so we can send you setup help and product updates. Both fields are optional, the wizard can be skipped, and nothing is sent if you leave them blank or do not consent.
AI processing
Generation is performed by the Hydrogen SEO API using AI model providers acting on its behalf, so the content of a request reaches those providers as part of producing your result. What is retained, and for how long, is set out in the privacy policy below.
Privacy policy: https://hydrogenseo.com/privacy
Terms of service: https://hydrogenseo.com/terms
External services
This plugin relies on the following third-party/external service. It is described here so you know what data is sent, when, and under which conditions.
Hydrogen SEO API
The plugin connects to the Hydrogen SEO API (hydrogenseo.com) for two things:
1. AI generation. Content generation and rewriting, metadata (SEO title and description) generation, image alt-text generation, AI image generation for featured images, and business/local schema generation.
Data is sent only when you actively use an AI feature. Depending on the feature the request includes the text or image you ask it to work with — a topic, the content to improve, an image URL for alt text, a prompt for image generation, or your business details for schema — together with your configured API key. When you connect your account, your site URL and the name and email you choose to provide are sent so an API key can be issued. The plugin does not send this data in the background or without a user action.
2. Hydrogen AI (the agent). When, and only when, you switch on AI Abilities and connect the agent, the plugin registers your site with the service. That registration sends your site URL, your WordPress username, a freshly created WordPress application password named “Hydrogen SEO Agent”, your WordPress version, the plugin version and your environment type, authenticated with your API key. The service verifies the credential by calling back into your site before storing it, keeps it encrypted (AES-256-GCM), and uses it to read and change SEO data on your behalf while you use the agent. Your instructions and the SEO data of the pages being worked on are sent as part of each conversation.
Agent access is gated three ways on your side: AI Abilities must be switched on, the abilities are locked to the domain they were enabled on, and only users with the manage_options capability can drive them. Disconnecting deletes the application password from your site; you can also revoke it from Users Profile Application Passwords at any time.
This service is provided by Hydrogen SEO. Terms of service: https://hydrogenseo.com/terms — Privacy policy: https://hydrogenseo.com/privacy