The context

From traffic lights to an assistant

For more than fifteen years Yoast SEO has been the reference for SEO on WordPress. It made on-page optimisation standard: the focus keyphrase, the readability traffic lights, XML sitemaps, metadata checks.

Today, people who run sites, newsrooms and online stores want more: bulk-optimise what they've already published, measure each language with an index built for it, fix things without opening every page, and get found by ChatGPT, Gemini and Perplexity too. AISA was built for this. It runs on its own, in place of Yoast, or alongside Yoast, Rank Math, SEOPress or AIOSEO, writing into their fields with no duplicates.

1 · Readability by language

The right formula for each language

AISA's Clarity panel picks the formula from the language of the text: Flesch for English, Gulpease for Italian, the index developed at Rome's La Sapienza university and based on word length in letters. The index is the first check in the traffic light. It's free, runs in the browser, in Gutenberg, the Classic editor and Elementor. And the score lands in a sortable "Readability" column in your content list.

Yoast has no Gulpease. Its Flesch score sits apart, in the Insights tab, and doesn't count towards the traffic light; word complexity is English-only. On the other hand, Yoast analyses many more languages: AISA covers Italian and English today.

Winner: AISA, for anyone writing in Italian.

2 · Audience profiles

Readability isn't one size fits all

Yoast applies the same thresholds to a recipe, a council notice and a legal opinion. In AISA you choose who you write for, site-wide or per piece of content. The readability threshold, sentence length and tolerated passive voice change with it.

Winner: AISA.

3 · Writing checks

A draw on analysis. Two different ways to fix

Clarity runs 9 checks as you write: readability index, long sentences and paragraphs, subheadings, passive voice, transition words, repeated sentence starts, text length and sentence variety. Yoast has a similar set, without sentence variety, and highlights issues right in the text: AISA lists them in the panel.

To fix them, both use AI in their paid plans. Yoast Premium's AI Optimize also fixes long sentences. AISA Premium's "Split long sentences" does something narrower: it splits sentences while keeping the author's words and their order, without rewriting. If a sentence can't be split cleanly, it leaves it alone and says why.

Winner: draw.

4 · Fixes and Data Optimization

From a single page to the whole archive

Yoast Premium has AI Generate for titles and meta descriptions, and AI Optimize, which fixes five checks: keyphrase in introduction, density, distribution, long paragraphs and long sentences. It works one page at a time, and you decide what to apply. AISA goes further in five ways.

Winner: AISA, if you need to fix what you've already published.

5 · GEO

Getting found by ChatGPT, Gemini and Perplexity

Yoast generates llms.txt even in the free plugin. With Yoast SEO AI+ ($358.80 a year plus VAT), AI Brand Insights checks every week how ChatGPT, Perplexity, Gemini and Claude talk about your brand. It's a good monitoring tool. AISA puts the emphasis on the work to do on your pages.

• llms.txt and AI Search Context for every page: what it covers, for whom, in which language.
• Questions and answers with FAQPage schema, plus a fact check: if an answer mentions opening hours, phone numbers or places that don't match your business data, AISA flags it before publishing.
• SEO Consultant: turns the searches that matter to you into real questions, asks Perplexity Sonar, OpenAI or Gemini with your key, scores your AI Visibility and shows which competitors get cited instead of you. In Premium it suggests the article to write, and can draft it in your style.
• Local SEO from Google Business Profile: your business data goes into the schema and, with Yoast active, completes its graph without duplicating it.

Winner: AISA for preparing pages and finding the gaps. Yoast AI+ if you want automatic weekly monitoring.

6 · AISA SEO Commander

SEO run from a chat with Claude

Since 2.0, AISA exposes its tools to AI assistants through the WordPress Abilities API and the Model Context Protocol (MCP). Instead of clicking through menus, you ask:

"Run an SEO audit of the Contact page, fix the failing checks and tell me what changed."
"Write the missing alt text for the product gallery with AISA Vision."

As of 2.0.5 there are 20 tools: 10 that read, in Free, and 10 that write and work in bulk, in Premium. Claude connects directly; ChatGPT goes through a third-party OAuth connector. With Yoast active, what you ask in the chat ends up in Yoast's fields.

Yoast has taken a step here too: it exposes 3 read-only abilities (SEO, readability and inclusive language scores) through the WordPress MCP Adapter. Reading scores is useful; fixing from the chat is a different job.

Winner: AISA.

7 · Architecture and pricing

AI included or your own keys, one site or thirty

• On its own or next to Yoast. The SEO transfer tool moves data from Yoast to AISA and back, with a backup before anything is touched.
• Local and staging too. Yoast's AI features, according to its FAQ, need a site reachable from the internet. AISA calls the provider from your site, so it works anywhere.
• Your keys or Cloud. Eight providers (Claude, OpenAI, Gemini, DeepSeek, Grok, GLM, Mistral, Perplexity) or the WordPress AI connector, paying the provider at its own price. Or AISA Cloud, no keys, with 500 credits included. Yoast includes AI in the subscription: convenient, but Yoast picks the model.

The FOUNDER50 discount applies to the first payment, for the first 500 licences. AISA Free, on WordPress.org, stays free.

Winner: AISA, especially for freelancers and agencies.

Summary

The table

Transparency

What we corrected in Gemini's analysis

Publishing an AI analysis as it is would be easy. But if it says something false about a competitor, one click is enough to disprove it. These are the points we changed.

• "Yoast's Flesch gives Italian text unjustified red lights." In Yoast, Flesch doesn't count towards the traffic light: it sits in the Insights tab.
• "Split long sentences is a feature no one else has." Yoast's AI Optimize fixes long sentences too. The difference is the method: AISA splits without rewriting.
• "Chat control: absent in Yoast." Yoast exposes 3 read-only abilities. What's absent is writing.
• "13 MCP tools, 5 read and 8 write." That was 2.0.0. As of 2.0.5 there are 20, 10 and 10.
• "AI+ costs €358.80 per site" and "€16,800 saved over 30 sites." AI+ is priced in dollars. For multiple sites Yoast gives a quote, so an exact saving can't be calculated.
• The Q&A fact check covers opening hours, phone numbers and places, not all business data. We also removed the "check the rendered page from the chat" example: it's not among the 2.0.5 tools.

An AI analysis is a source, not a ruling. It needs checking like everything else.

Conclusion

Which to choose, and why you don't have to choose yet

If you want a proven tool that guides writers page by page, with AI included in the subscription, Yoast SEO remains a solid choice.

If you want readability measured with the right formula for your language, thresholds fitted to your audience, the whole site optimised in the background, images described by looking at them, work on your visibility in AI answers and SEO run from a chat with Claude, AISA does more today.

And you don't have to uninstall Yoast to try it. AISA Free recognises Yoast, including the free version, and writes into its fields. The side-by-side comparison with prices and features is in AISA and Yoast SEO: together, or just one?