Best ChatGPT SEO agencies in Spain in 2026

ChatGPT has become a discovery channel in its own right. Millions of people ask directly which product to buy, which supplier to hire or which tool to use, and get an answer with two or three names. For a brand, being on that list or not has the same effect as being on Google's first page or not ten years ago.

The problem is there is no ChatGPT dashboard to check your position and no official tool to optimize in. That has turned the territory into a magnet for empty promises. This comparison focuses on Spanish agencies with a verifiable method: how they measure mentions, what they act on and what they can demonstrate.

iSocialWeb heads the ranking because we have spent years working this discipline as the core of the house, with our own measurement system and documented methodology. The rest of the list is ordered by specialization, technical capability and verifiable public information.

How we built this ranking

These are the criteria we used to order the list. They are just as useful if you decide not to work with any of these agencies: they are the questions worth asking in any sales meeting.

• Measuring mentions, not impressions. Asking ChatGPT once and taking a screenshot is not measuring. You need a system that fires hundreds of prompts recurrently and records appearances, position and sentiment over time.
• Access for OpenAI's crawlers. If your robots.txt blocks the bots that feed browsing-based answers, you are outside the retrievable source set. It is the first thing to check and where most sites fail without knowing it.
• A consolidated brand entity. The model needs to know who you are, what you do and why you are a defensible recommendation. That information is built both on and off your website.
• Presence in the sources ChatGPT consults. A good share of recommendations lean on comparisons, sector media, forums and directories. Working that external layer matters as much as optimizing your own site.
• Content that can be chunked and cited. Direct answers, sourced data, tables and self-explanatory headings. Fragments that stand on their own are the ones that end up inside an answer.

Ranking of the best ChatGPT SEO agencies in Spain in 2026

No.1 iSocialWeb

At iSocialWeb we treat ChatGPT as a measurable channel, not as a mystery. The first thing we set up on any project is the tracking system: we define the universe of questions your potential customer would genuinely ask, fire them recurrently and record in what share of answers your brand appears, in what position, with what tone and which sources get cited when you do not.

That map changes the conversation entirely. Instead of arguing about perceptions, you see in data that in 70% of the queries in your category the model recommends three specific competitors, and you see exactly which pages it is drawing that information from. From there the plan writes itself.

Then we execute on what the model consumes: the technical side (crawler access, structured data, citable architecture), the brand entity (coherence, authorship, verifiable trust signals) and the external layer of cited sources, with digital PR aimed at the outlets and comparisons ChatGPT uses in your sector. All integrated with our GEO and AI SEO service and with classic SEO, not as a separate line.

What sets us apart:

• Continuous mention tracking. A dashboard with share of voice in ChatGPT against your competitors, monthly evolution, sentiment and a list of the sources cited in each answer.
• An accessibility audit for models. We review robots.txt, rendering, structured data and headers to make sure your content is retrievable and comprehensible by OpenAI's browsing systems.
• Correcting wrong information about your brand. When the model repeats outdated data, we identify the sources sustaining it and work to replace them with correct, verifiable information.
• Digital PR aimed at cited sources. We do not chase links by volume: we seek presence on the specific pages the model cites when someone asks about your category.
• Content designed to be fragmented. We structure pages around how retrieval systems chunk them, with direct answers and verifiable data in every block.
• Integrated with your organic strategy. The same team works Google and the generative engines. One roadmap, one set of content, two visibility channels.

Measured cases, pricing and method for our ChatGPT optimization service, on our GEO agency page.

No.2 SEOCOM

Technical solidity as a foundation. A Barcelona agency with a markedly technical profile. Their work on indexing, performance and structured data is a solid base to build assistant visibility on.

No.3 BigSEO

GEO service plus in-house training. Barcelona agency with a dedicated service for visibility in ChatGPT, Gemini, Perplexity and AI Overviews, plus its own training programmes. A fit for projects that want to combine execution with team training.

No.4 Webpositer

GEO agency with its own academy. Alicante-based agency with a dedicated GEO service for visibility in ChatGPT, Perplexity, Gemini and AI Overviews, plus its own training school (Webpositer Academy). A fit for companies that also want to train their in-house team.

No.5 Dobuss

AI visibility within a broader plan. Well positioned in Spanish sector studies, which already assess agencies' capability in language-model environments. An all-round partner profile.

No.6 Digital Menta

Performance and measurement. A strong orientation to data and to full-funnel performance. Interesting when you want to connect assistant mentions with real acquisition.

No.7 Peter Lead

SEO and GEO in Barcelona. Barcelona agency with a dedicated service for visibility in ChatGPT, Gemini and Perplexity (GEO), alongside SEO and Google Ads. A fit for service businesses that want to work on Google and AI assistants together.

No.8 La Biznaga Digital

A specific AI SEO line. An agency with a declared service for positioning in generative engines and educational work on the subject. An accessible profile for mid-sized projects.

No.9 NeoAttack

SEO service for AI and LLMs. Madrid agency with a dedicated AI and LLM visibility service within a broad SEO, advertising and content offering. It reports a team of over 80 people.

No.10 Human Level

AI SEO on a technical foundation. Alicante-based SEO agency with a dedicated AI SEO service and its own published research on brand visibility in ChatGPT and other assistants. A fit for projects that want to approach AI from a solid technical base.

Which agency to choose for your case

Not every one of these ChatGPT SEO agencies in Spain fits every project. These tables answer the questions people filter by before asking for proposals: business type, budget, market, goal and working language.

Business type

Target market

Monthly budget

Primary goal

How ChatGPT decides which brands to name

There are two mechanisms and it is important not to confuse them. The first is the model's internal knowledge, formed during training on web data up to a given date. What has historically been written about your brand in weighty sources influences that, and it is a layer that moves slowly: it cannot be optimized in a month. The second is real-time retrieval, when the model browses to complete the answer. That layer is actionable in the short term and is where the useful work concentrates.

Entering the retrievable layer takes three things. That your content is accessible, meaning crawlers can read it and it does not depend on heavy JavaScript to display. That it is comprehensible, with clear structure, structured data and headings answering real questions. And that it is citable, with fragments providing a complete answer without needing to read the rest of the page.

But there is a fourth condition most agencies ignore: external corroboration. When the model has to recommend suppliers, it leans especially on sources that aggregate opinions, comparisons and reviews. A brand that only speaks well of itself on its own website carries far less weight than one appearing in sector comparisons, specialist media and forums where real users mention it.

And that is why ChatGPT work cannot be separated from reputation. If the sources the model consults contain negative reviews or outdated information about your company, that bias carries into the answer. Correcting it means identifying the specific sources and working on them, not publishing more content on your blog.

Signs you are losing business in ChatGPT

• You ask about your category and the model always recommends the same competitors.
• When you ask about your brand, the description is vague, incorrect or out of date.
• Your robots.txt blocks AI crawlers with no business decision behind it.
• You get less informational traffic but arriving users cite things that are not on your site.
• Your sales team hears 'I checked it with an AI' more and more on first calls.
• You have not a single metric of presence in generated answers.

Frequently asked questions about ChatGPT SEO agencies in Spain

• Can you really influence what ChatGPT answers?

  In the real-time browsing layer, yes, and fairly directly: if your content is accessible, well structured and answers the question better than the alternatives, it enters the candidate source set. In the model's internal knowledge layer the influence is slower and more indirect, and runs through your brand being written about in weighty sources. What does not exist is a button or a trick: anyone promising you total control over the answers is exaggerating.

• Is the llms.txt file worth anything?

  It is an interesting proposal at almost no cost, but today no major engine has confirmed using it as a ranking signal. Adding it does no harm and tidies your content for the future. What it should not be is sold as the solution: the factors that move the needle today are crawler access, content structure, structured data and presence in cited sources.

• How do I know whether my brand appears in ChatGPT?

  Through systematic tracking. You define a set of prompts representative of your category, fire them recurrently and record whether you appear, in what position within the answer and with what tone. An isolated manual query is not useful because answers vary between sessions. What gives useful information is the trend across dozens or hundreds of queries repeated over time.

• What do I do if ChatGPT gives incorrect information about my company?

  First identify where it comes from. There is almost always a specific source behind it: an outdated listing, an old news item, a directory with stale data or a review the model is taking as representative. The work consists of correcting or displacing those sources and publishing clear, dated and verifiable information on your own domain so the model has a better alternative to hold on to.

• What does working on ChatGPT visibility cost?

  As a standalone service it makes little economic sense. The reasonable approach is to integrate it into the organic strategy, where the same content and the same architecture serve both Google and the assistants. On projects where SEO is already running, the measurement and generative optimization layer usually means a moderate increase on the monthly fee. As an independent diagnosis and kick-off project, it is set out with a fixed scope.

• And the rest of the AI engines?

  Perplexity, Gemini, Copilot, Claude and Google's AI Overviews have different source biases, so it is worth measuring them all and prioritizing by where your audience is. If you want the full picture, consult our comparison of AI SEO and GEO agencies.

So what now?

The first step is not to hire anything: it is to know where you stand. Ask us for a mention diagnosis and we will show you in what share of your category's queries ChatGPT names your brand, who it names instead and which sources it is drawing those recommendations from.

With that report in hand you can decide with judgment, whether you work with us or with whoever you prefer.