Best LLM SEO agency for generative search strategies in 2025

TL;DR: No single agency is the best, because the field is barely a year old and half the shops calling themselves GEO experts rebranded last quarter. The ones worth hiring pair real technical SEO depth with a working understanding of how language models retrieve and cite. Budget $3,000 to $15,000 a month for a credible retainer. This guide shows you how to tell the two apart.

What does an LLM SEO agency actually do?

The job is not classic SEO with a new label. An LLM SEO agency, also called a GEO agency or AEO (answer engine optimization) agency, works to make your brand the answer that ChatGPT, Gemini, Claude, and Perplexity name when someone asks a question in your category. That means structuring content so language models read it as authoritative, earning citations from the pages those models already trust, and making your brand name show up in the data those systems pull from.

Traditional SEO chases a ranked link. Generative search produces a typed or spoken answer where your brand is either named or missing. There is no position two. You get cited or you don't.

That binary is what makes this different, and it's why an agency that only knows Google rankings struggles here.

Good LLM SEO work breaks into four streams. Content restructuring for extractability, which means writing in a format a model can lift cleanly. Entity authority building, which means making knowledge graphs and structured data clearly tie your brand to its category. Citation-source targeting, which means getting your brand mentioned on the pages models lean on. And measurement, which means tracking actual AI citation rates instead of keyword positions. An agency that can't describe those four areas in plain language isn't ready for the work. [1]

For a fuller picture of how this discipline works, see our overview of generative engine optimization.

How is generative engine optimization different from traditional SEO?

Classic SEO sends signals that tell a search engine to rank a URL higher: backlinks, page speed, keyword coverage, click-through rate. Generative engine optimization (GEO) does something else. It makes content a language model will pull from when it builds an answer, and it works to get your brand named inside that answer.

A 2023 study titled "GEO: Generative Engine Optimization" from researchers at Princeton, Georgia Tech, and IIT Delhi, posted on arXiv, tested this directly. It found that adding citations, quotable statistics, and fluent authoritative sentences to content raised its visibility in AI-generated responses by up to 40% depending on the query type. [2] The authors wrote that these methods "can boost source visibility by up to 40%." That paper is the closest thing the field has to a controlled baseline, and it's worth reading in full.

The second big difference is retrieval. Generative search doesn't crawl your site every few weeks scanning keywords. Models are trained on snapshots, and the real-time retrieval layer that Perplexity and Gemini's grounding system pull from leans heavily toward sources the model already treated as authoritative during training. So you fight on two fronts: what sits in the model's weights, and what surfaces through the retrieval-augmented generation (RAG) layer on top. [3]

Agencies that don't grasp the training-versus-RAG split give advice that only touches the retrieval layer. Better than nothing, but it misses half the game. The best agencies know which tactic hits which layer, and they say out loud what they can't influence. Track the gap using AI search visibility metrics and KPIs.

See our explainer on AI SEO for the technical foundations before you start talking to agencies.

What should you look for when evaluating an LLM SEO agency?

This is where buyers get fooled. The field is young enough that almost any shop can claim GEO expertise with nothing to back it up. Here's what to actually scrutinize.

Start with proprietary measurement. Any agency serious about AI visibility has built or licensed a way to track citation rates across ChatGPT, Perplexity, Gemini, and Claude. If their reporting is Google Analytics plus rank tracking, they're doing old SEO with a fresh label. Ask to see a sample client dashboard. Ask exactly what they use to track AI mentions. [4]

Next, demand a before-and-after on AI citation rate, not organic traffic. Traffic climbs for reasons that have nothing to do with generative search. You want proof that the content they restructured started showing up in AI answers. That's hard to fake, because you can rerun the same queries yourself in five minutes.

Check the content team's background. The strongest GEO work right now comes from people who understand how models are trained: NLP researchers, prompt engineers, technical writers who think in information structure. A team of pure blog writers produces content that reads well to humans and gets ignored by machines.

Ask about entity authority by name. Schema markup, knowledge panel work, Wikipedia and Wikidata presence, brand mentions in trusted publications. Those signals help a model tie your brand to a category with confidence. No clear entity-building process means a real gap.

Understand their link approach. GEO still needs earned links, but the targets shift. You want links from pages models trust hard: major publications, government sources, university pages, busy Q&A communities like Reddit and Quora. Generic link farms do close to nothing here. [5]

The AI visibility tool landscape has matured enough that you can cross-check agency claims yourself before you sign anything.

AI citation source concentration in Perplexity responses

| | | |---|---| | Top 20% of sources by authority | 80% | | Next 30% of sources by authority | 15% | | Bottom 50% of sources by authority | 5% |

Source: Search Engine Journal, Perplexity AI citation analysis, 2024

What are the red flags that an agency is just rebranding old SEO as GEO?

The loudest red flag: they lead with keyword rankings as the headline success metric. Keywords still feed the retrieval layer, but if the entire pitch is moving you from position 8 to position 3 on a keyword list, there's no real GEO practice underneath.

Second flag: they can't explain the difference between how a model is trained and how RAG retrieval works at inference time. It's a basic distinction. A vague answer or a hand-wave means they aren't equipped for the level generative search demands.

Third: they promise a specific citation rate. Nobody can. The models are black boxes. The honest pitch is that their approach gives your content the structure and authority signals that correlate with higher citation rates, based on research and testing. Anyone guaranteeing a number is inventing it. [6]

Fourth: their case studies show only organic traffic gains and no AI visibility data. Ask for a case study about AI answer inclusion. If they don't have one, they've never measured it.

Fifth: they charge per keyword optimized. That's a traditional pricing model, and it maps badly to GEO, which is about content structure, entity authority, and citation coverage across a topic, not single keyword positions.

Sixth: they haven't thought about which assistants your customers actually use. Optimizing for Perplexity is not the same as optimizing for ChatGPT's browsing behavior, which is not the same as Google AI Mode. A real practice knows those differences cold.

How much does an LLM SEO agency cost in 2025?

Honest answer: pricing is all over the map because the market is young. Here's the range I've actually seen.

| Tier | Monthly Retainer | What You Get | |---|---|---| | Boutique specialist (1-5 person team) | $2,500 - $6,000 | Content restructuring, entity markup, light citation building, monthly reporting | | Mid-size agency with GEO practice | $6,000 - $15,000 | Full content strategy, entity authority program, citation-source outreach, AI visibility dashboards | | Large agency with AI/search division | $15,000 - $40,000+ | Dedicated team, proprietary tooling, competitor AI share monitoring, integrated PR strategy | | Project-based audit + roadmap | $5,000 - $25,000 (one-time) | Point-in-time assessment, no ongoing execution |

The boutique tier suits companies early in GEO work who want to test the approach before scaling. The catch: the smallest shops often lack dedicated measurement, so you're trusting their gut on what's working without much data underneath.

For most mid-market companies with real budgets, the sweet spot is $8,000 to $15,000 a month, and only for an agency with actual AI visibility tracking, a documented content restructuring method, and at least one person on the team with genuine NLP or LLM background.

Don't pay above $20,000 a month until you've confirmed the agency moves your citation rates in a way you can measure. At the high end you're often paying for a brand name, not better execution. [7]

Some agencies now tie a slice of the fee to measured citation improvement. That alignment is worth seeking, though both sides have to agree on a measurement method upfront, which is its own fight.

Which agencies are actually known for generative search expertise in 2025?

Let me be straight: this field is young enough that verifiable case studies with hard AI-citation data are scarce. Most agency reputation right now rests on thought leadership, not client outcomes with real numbers. That's a limitation worth naming out loud.

With that caveat, the agencies most often cited in the GEO/AEO space are a mix of specialist boutiques and older SEO shops that built genuine AI practices. Names go stale fast, so I'll describe the types to look for instead.

Specialist GEO-only agencies launched specifically for this space, staffed by people with ML or NLP backgrounds who built their measurement tools from scratch. They tend to be small, pricey, and hard to find. They also tend to have the technical depth you actually need. Hunt for their principals' writing on Substack, on arXiv, and in SEO conference talks from the past 18 months.

Traditional SEO agencies with GEO practices are the bigger firms, Conductor, BrightEdge, Clearscope's agency partners, and similar names, that bolted GEO onto existing teams. Quality swings wildly inside these firms. The real question isn't whether the agency has GEO capability. It's whether the specific team you'd work with does.

In-house models deserve a look too. Some of the sharpest GEO work in 2025 is coming from companies that hire one or two specialists internally, buy a good AI SEO tools platform, and skip the agency layer. That works if you can afford senior talent and don't need an agency's breadth. [8]

Before you sign with anyone, run three or four category queries through ChatGPT, Perplexity, and Gemini and note which brands they name. Then ask each shortlisted agency to explain why those brands get cited. The answer tells you almost everything.

What questions should you ask an LLM SEO agency before hiring them?

Seven questions for every agency in your final shortlist. Take notes and compare the answers side by side.

1. How do you measure AI citation rate, and which assistants do you track? A real answer names specific tools or methods and covers at least three platforms. A weak answer pivots back to rank tracking.

2. Can you show me content you restructured and the before/after in AI citation performance? If they can't show it, they've never measured it.

3. What is your entity authority process, and how do you handle schema markup and knowledge graph signals? They should walk you through a specific workflow, not a slogan.

4. How do you separate training-time influence from RAG retrieval-time influence? A blank look means they don't understand the problem well enough.

5. Which sources do you target for citation building, and how do you prioritize them? Good answers mention high-authority publications, Wikipedia and Wikidata, .gov and .edu sources, and communities models pull from like Reddit and Quora. [9]

6. How do you handle the pace of model updates? OpenAI and Google change retrieval and ranking behavior regularly. A good agency has a process for watching those shifts.

7. What does reporting look like, and how often do we meet? Monthly citation reports plus quarterly strategy reviews is reasonable. Anything less frequent than monthly means they aren't watching closely.

These seven separate a real practice from a traditional shop with new slides on the deck.

How do AI search behavior studies inform what a good agency should be doing?

A handful of real studies exist, and they form the honest foundation for what agencies should do. The Princeton and Georgia Tech GEO paper mentioned earlier is the most cited, but a few others matter. [2]

Analysis of how Perplexity selects sources for citation shows heavy concentration: the top 20% of sources by domain authority take roughly 80% of citations. [10] That's a brutal Pareto curve, and it tells you citation-source targeting is not optional. If your brand isn't mentioned in high-authority publications, you're mostly invisible in Perplexity answers.

Research on Google's AI Overviews published in Search Engine Land through 2024 and 2025 found that AI Overview appearances correlate with ranking in the top 10 organic results, but correlation isn't causation and the link is loose. Roughly 30% to 40% of AI Overview sources don't appear in the top 10 organic results for the same query. [11] Pure ranking gains aren't enough for AI visibility, and agencies that only chase rankings leave citations on the table.

The studies converge on three findings. Authoritative sentence-level answers, direct citation of reputable sources inside your content, and clear entity associations are the strongest correlates of AI citation inclusion. A good agency builds a strategy around all three at once, not one in isolation. [2]

The AI powered search features overview covers how different retrieval systems are built, which explains why these findings look the way they do.

Should you hire an agency or build an in-house GEO capability?

This comes down to one thing more than any other: whether you can find and afford the right one or two people to hire full-time.

The case for in-house is clean. You keep the institutional knowledge, you control the measurement stack, and you skip the agency markup on labor. A senior GEO strategist with real LLM fluency runs $120,000 to $180,000 a year in salary. [12] Over 12 months that's cheaper than a $12,000-a-month retainer, and you get someone who thinks about your brand and nothing else.

The case for an agency is speed. You get a team without the ramp time, you benefit from patterns they've seen across clients (what tends to work for SaaS in general, more than your slice of it), and you can scale back down without a layoff if priorities move. Agencies are also quicker to evaluate than hires, which matters when the ground shifts this fast.

My honest read: if you're spending over $10,000 a month on an agency and you've been at it for six months, ask whether that money would fund a full-time hire plus a good AI visibility tool subscription instead. The agency model earns its keep in the first six to twelve months, while you're still learning what GEO work involves and haven't defined what success looks like in your category.

If you go in-house, don't hand GEO to your existing content team without real training and tools. It needs a different mental model than blog SEO. The team will default to what they know, and what they know isn't enough for generative search.

What tools should your agency or in-house team use to track AI search visibility?

Measurement is the hardest practical part of GEO right now. In traditional SEO, rank tracking is commoditized and accurate. AI citation tracking is genuinely hard. The models don't expose APIs for it. You have to query them over and over with representative questions and record whether your brand shows up. [13]

The current landscape includes several dedicated platforms that run automated query sets against ChatGPT, Perplexity, Gemini, and Claude and track brand citation rates over time. As of mid-2025 that group includes Profound, Otterly.ai, Brandwatch's AI monitoring add-on, and a batch of GEO analytics tools launched in the past 18 months.

Spawned's own AI visibility audit tooling runs this kind of tracking and shows your current citation baseline before you hire anyone. Do that first, so you walk into agency conversations with real numbers to benchmark against.

Any agency worth hiring already has a recommended measurement stack and will work with your existing tools if you have them. Insisting on proprietary-only dashboards with no data portability is a lock-in red flag.

For a wider view, the AI SEO tools comparison covers the major platforms with current pricing and features.

How does Google AI Mode change what LLM SEO agencies should be doing?

Google AI Mode, which rolled out broadly to US users in May 2025, raised the stakes hard. [14] AI Overviews appeared above traditional results for a subset of queries. AI Mode replaces the results page for a much wider class of searches. If your brand isn't in the AI Mode answer, many users never see your organic result at all.

What that means for agencies: AI Mode pulls heavily from Google's own index, so on-page SEO and link signals still count, but the way answers get built has changed. AI Mode synthesizes across several sources rather than featuring one result, so showing up usually means being mentioned across multiple high-authority pages, more than ranking one page beautifully.

This is where GEO and traditional SEO actually converge. Getting your brand named authoritatively across many trusted sources helps both. Where they split is format. AI Mode favors structured, directly-answering content over long narrative. If your strategy is 2,500-word exploratory blog posts, AI Mode often skips them for shorter, sharper answers from Wikipedia, Reddit, or structured FAQ pages. [11]

An agency that hasn't changed its approach since AI Mode launched is behind. Ask them straight: how has your content strategy changed since Google AI Mode rolled out? The answer shows whether they're paying attention. See our full coverage at Google AI search.

What does a realistic LLM SEO engagement timeline look like?

Expect three to six months minimum before you see real movement in citation rates, and even that is optimistic depending on your starting authority and how competitive your category is.

Month one is audit and baseline. The agency maps your current citation rate across target queries, finds gaps in entity authority and content structure, and builds a prioritized roadmap. No visible results yet. An agency promising visible results in month one is lying.

Months two and three are content restructuring and entity work. High-authority pages get reformatted for extraction, schema markup gets implemented or fixed, knowledge graph signals get updated, and citation-source outreach begins.

Months four through six are when the data starts meaning something. Citation rates on target queries should be moving if the work is good. This is also when you'll have enough evidence to judge whether the approach works for your category and audience.

Six months is a fair minimum before drawing conclusions. Shorter runs produce so little data that success and failure blur together. Agencies that offer month-to-month deals with no minimum are either very confident or very willing to churn clients before results are due.

For how to think about what you're measuring across that window, the AI search visibility metrics and KPIs guide covers the specific metrics worth tracking and what realistic improvement curves look like.

Sources

1. Search Engine Journal, Generative Engine Optimization overview
2. arXiv, GEO: Generative Engine Optimization (Aggarwal et al., Princeton, Georgia Tech, IIT Delhi, 2023)
3. Google DeepMind, Retrieval-Augmented Generation overview
4. Moz Blog, AI search measurement and tracking approaches
5. Search Engine Land, AI Overview source analysis 2024
6. MIT Technology Review, AI search opacity and predictability
7. Forrester Research, AI marketing services pricing benchmarks
8. Bureau of Labor Statistics, Occupational Outlook Handbook, SEO and digital marketing specialists
9. Wikidata, Wikidata for AI entity recognition documentation
10. Search Engine Journal, Perplexity AI citation source concentration analysis 2024
11. Search Engine Land, Google AI Overviews correlation with organic rankings, 2024
12. Glassdoor, GEO and AI SEO specialist salary data 2025
13. Stanford HAI, AI Index Report 2024
14. Google Blog, AI Mode launch announcement, May 2025