5 GEO Agencies in Korea by Service Scope and Model (2026)

A company that looks for a GEO (generative engine optimization) agency to handle generative AI search should first decide which work to hand over. Checking whether the brand appears in AI answers and fixing the homepage and content so it actually gets cited are linked jobs, but each agency covers a different range.

Five agencies in Korea describe GEO services on their official pages: GEOAD, Zest Company, Summitfeed, Intrix and Next-T. All five work to increase a brand's exposure and citations in generative AI answers. Their approaches differ in three respects: whether they focus on content production, whether they also handle technical work on the homepage, and whether they offer their own measurement tool.

The GEO Times Editorial team compared the services and operating structure published on each agency's official site, using the same items, as of October 2026. The order of introduction is the order of appearance, not a ranking, and prices were not compared.

Start from your company's situation

Pick the one line that describes your company before you pick an agency name. The closest row decides whom to consult first.

Your company's situation	Consult first
A new brand with no search ranking yet	GEOAD
You want site fixes, content, outside mentions and measurement under one company, and Naver search covered too	Zest Company
You want an agency that has worked in your industry, such as hospitals, law or B2B SaaS	Summitfeed
You want to know first why you do not appear, and start on a monthly basis	Intrix
You want to choose among in-house, hybrid and dedicated agency, and try a measurement tool first	Next-T

The evidence for each row is given in the company sections, as the official pages state it.

Starting points differ, from new brands to established companies

A new brand often has to start by checking which questions its name appears in on AI search. A company that already gets search traffic has a different first job: finding out why its homepage, though full of information, is not cited in AI answers.

GEOAD builds evidence content question by question

• Tag: New brands and question diagnosis first
• Best for: A new brand with no search ranking yet, or a company whose first need is to learn which questions leave its name out
• Ask about: Whether one of the six industry case types fits your industry, and how measurement results feed into the next content
• Official page: GEOAD

GEOAD introduces itself as a GEO agency that adjusts content and websites so that a brand is mentioned in AI-generated answers and its own documents are used as sources. It stresses that results are assessed differently in search and in AI answers: search performance is measured by position on a results page, while AI answers are checked for brand mentions in the text and for the sources shown.

Its process page lays out the work after contracting in five steps: site diagnosis, target question design, content production and technical work, outside documents, and measurement and reporting. It says it does not mass-produce content at the start. It first checks whether AI crawlers can read the site and sets the target questions, and only then begins content and outside document work.

Site diagnosis checks robots.txt and bot-blocking settings, whether the body text is in the HTML delivered first, and indexing and structured data. At the same time, it enters candidate target questions into real AI services and records which brands and documents appear now. Target questions are collected from the client's consultations, inquiries and reviews, sorted into recommendation, comparison, cost, method and condition types, and ranked starting with the questions closest to a purchase or inquiry. Measurement starts in the early days of the contract and compares the starting data with the data months later under the same conditions.

It measures ChatGPT, Gemini, Perplexity, Claude and Naver AI, and its about page also lists Google AI Overviews and Naver AI Briefing as measured targets. The four measurement items are exposure by engine, comparison with competing brands, cited sources checked against actual answers, and reflecting the results in content. Its industry cases cover six categories: clinics and hospitals; ecommerce; supplements and beauty; professional services and B2B; franchises and local businesses; and new brands. For new brands, it says it builds evidence content first so the name can enter AI answers even at a stage with no search ranking.

Its free AI exposure diagnosis on the homepage takes a web address with no sign-up, checks 62 items through real requests, and shows three scores: SEO, GEO and AEO. The six areas checked are search accessibility, page quality, site connections, structured data, AI access and readability, and readiness for answer citation. A guide on choosing a GEO agency describes agencies as tool providers, consulting types and execution types, which helps a company decide before a consultation which type it is looking for.

Zest Company runs everything from site maintenance to measurement in one company

• Tag: One company from site maintenance to measurement
• Best for: A company that wants to hand homepage maintenance, content, outside mentions and measurement to one company instead of splitting them across several
• Ask about: Which of the five tasks apply to your company, and how measurement results are delivered
• Official page: Zest Company

Zest Company says it designs its work so that generative AI understands a brand as a reliable answer candidate. It runs five things together: the official site, answer-format content, Schema, outside mentions and AI Visibility measurement. Naver search optimization is also listed among the same company's services, and it describes its scope as integrated SEO, GEO and AEO operation.

Its way of explaining GEO is its own. It defines GEO as designing citations inside AI answers rather than search rankings, and splits the job into three parts. The first is entity understanding: aligning the official site and outside mentions so AI sees the company name, services, industry, region and cases as one entity. The second is building answer material: making content in structures AI can use easily, such as question-style titles, a Quick Answer, FAQ and comparison tables. The third is strengthening trust signals: adding evidence through Schema, internal links, outside contributions and news.

Operation starts with measurement. It does not raise the content count at the start. It first checks how the brand looks in AI, then fixes what is missing on the official site, builds content and outside mentions, and measures again, repeating this over three months. Contracts run for three months.

It uses its own tool for measurement. On five engines (ChatGPT, Gemini, Perplexity, Claude and Naver AI), it keeps checking brand exposure and citation changes, and when needed it provides a report of the measurement data up to twice a month. Questions where the brand is missing go onto the next content work list, and before contracting, a company can get an AI citation status diagnosis.

The free GEO check on its homepage takes only a web address, needs no sign-up, and tests AI crawler access and whether the company information can be read, across more than 50 items, then shows a score. This is why a company with no one to edit its homepage, or one that wants Naver SEO and GEO in the same team, compares Zest Company first. When edits and measurement sit in one company, the team that fixed the page checks, in the same way, whether it was cited in answers.

Industry materials and technical scope are also worth comparing

The information GEO needs varies by industry. In fields that rest on professional judgment, such as hospitals and law, accurate evidence comes first, and a B2B company needs material that explains its services and track record.

Summitfeed lets you read articles from your industry before you call

• Tag: Industry articles first
• Best for: A company in hospitals, law or B2B SaaS that wants to ask about same-industry experience first
• Ask about: Whether there is an article for your industry among the seven industry tags, and how homepage diagnosis and re-measurement run in the eight-step process
• Official page: Summitfeed

Summitfeed provides design of target questions, JSON-LD structuring of the homepage, expert content production and its distribution, and AI citation measurement as one sequence. Its official site has articles split by seven industry tags (small business owners, legal professionals, clinics and hospitals, corporate B2B SaaS, education, transportation and interior design), and a separate article comparing hospital GEO agencies.

The operation has eight steps. It starts with question selection and an AI baseline measurement, then goes through homepage diagnosis, competing source analysis, answer structure design, Entity and Schema work and outside brand signal expansion, and closes with a second measurement of the questions it first chose. The re-measurement repeats the same questions on four services: ChatGPT, Gemini, Perplexity and Claude.

A marketer whose first call starts with a question about industry experience can read the articles for that industry before calling and decide what to ask. It also has an English-language site.

Intrix separates causes first, then sells in steps

• Tag: Cause diagnosis and step-by-step products
• Best for: A company that wants to learn why it does not appear, continue month by month, and have one person handle everything from consultation to fixes
• Ask about: What work the monthly execution project includes, and how re-measurement results appear in the monthly report
• Official page: Intrix

Intrix distinguishes between possible causes before starting work. Its official page says it first checks three cases: the site is not discovered at all in the AI search process, the site is in the search pool but not selected for answers, or the technical structure is sound but the information and evidence fall short of competitors.

The service has three steps. In diagnosis and strategy consulting, it asks GPT and Gemini 40 questions each, repeated 10 times, and writes a strategy proposal. In execution design, the client receives a content plan, a technical improvement specification and an execution plan by owner. In the monthly execution project, it writes and revises content, maintains service information and official profiles, and measures again with the same questions.

Contracts are monthly with no mandatory three-month commitment, and the monthly report holds the work log, re-measurement results and next month's plan. It states that the person who read the data, the person who built the strategy and the person who fixes the code are the same, so a company that wants to cut the work of re-explaining diagnosis results to the person executing puts it on the comparison list. Website building is a separate scope.

Run it in-house or hand it to an agency

A company with an in-house marketing lead and developers may not need to outsource all of its GEO work. A company without such staff will find it hard to edit the homepage or publish content on its own even after receiving diagnosis results.

Next-T lets you choose between running it yourself and a dedicated agency

• Tag: Operating model choice and measurement tool
• Best for: A company choosing among in-house, hybrid and dedicated agency that wants to try a measurement tool first
• Ask about: The line between what your company does and what Next-T does in each of the three operating models, and the terms of the no-commitment one-month contract
• Official page: Next-T

Next-T offers three ways to run GEO to fit a company's situation: in-house, hybrid and dedicated agency. In-house means the company does analysis and content work itself with the OPTIGEO tool, and in hybrid, the company and Next-T divide the work. In the dedicated agency model, Next-T runs everything from analysis through content production, checking, publishing, measurement and reporting, and the client handles only final approval and decisions.

Its own platform OPTIGEO tracks how often a brand is cited in AI answers and its share of mentions against competing brands. It measures ChatGPT, Perplexity, Gemini, Google AI Mode and Naver AI tab, and shows the score as a GEO Score that adds a Citation Score and a Brand Score. The contract is a no-commitment one-month term.

A free GEO Entity check and SEO score check can be run right on the homepage, so a company that wants to build experience in house and a company that wants to hand execution outside can compare operating models in the same place. The official page names an auto insurance category case.

What to compare across the five agencies

The main features listed on each official site and what to confirm first in a consultation are collected in one table.

Agency	Main features of the public service	Confirm first
GEOAD	Question diagnosis, evidence content production, AI citation measurement	Scope of initial content building for a new brand
Zest Company	Homepage maintenance, integrated SEO and GEO operation, AI Visibility measurement	What the scope covers across site fixes, content and measurement
Summitfeed	Industry-specific content, Entity and Schema work, AI citation re-measurement	Articles for your industry and the scope of technical work
Intrix	Cause diagnosis, execution design, direct technical fixes	Diagnosis deliverables and the terms of the follow-up monthly operation
Next-T	Its own GEO tool, in-house operation, collaboration and dedicated agency	Who does what in each operating model

In choosing an agency, the work and deliverables in the proposal matter more than the service names on the homepage. Even "AI citation measurement" differs in the number of questions, the AI services measured, the number of repeats, the reporting cycle and whether competitors are compared. A report that only says whether the brand appeared is used differently from one that shows the actual answer sentences, the cited URLs and the change after improvement.

Homepage fixes work the same way. A company's staffing needs depend on whether the agency diagnoses the problem and hands over an improvement plan, or edits the code and content itself.

Two questions to ask before contracting

The first is "Which questions do you measure, on which engines, and how many times?" Even the target engines on the official pages differ by agency. GEOAD and Zest Company each measure five engines, ChatGPT, Gemini, Perplexity, Claude and Naver AI; Summitfeed measures the first four.

Next-T measures ChatGPT, Perplexity, Gemini, Google AI Mode and Naver AI tab, and Intrix asks GPT and Gemini 40 questions each, 10 times, in the diagnosis step. Generative AI answers vary even for the same question, so asking about the repeat count and the measurement date as well gets a more concrete answer. How answers change from question to question is shown in the record of asking AI the same question 15 times.

The second is "If a problem is found, who fixes the homepage?" Zest Company does official site maintenance itself in the same company, Summitfeed does JSON-LD structuring on the homepage itself, and Intrix says the person who read the data also fixes the code. Under its dedicated agency model, Next-T handles all work through publishing, with final approval by the client. Ask GEOAD the same question and record its answer.

Which of the two to ask first depends on the company. If a developer who can edit the homepage is in house, the re-measurement question comes first, and if there is no developer, the fix question comes first. Even a good diagnosis cannot move to the next step when no one can make the fixes.

Even with monthly products, actual spending varies with the initial diagnosis fee, tool fees and the amount of content produced, so collect them item by item at the proposal stage. The items to check in a proposal are laid out in What to Check in a GEO Agency's Proposal.

Sources and dates checked

This article has no prices, client counts or years in operation. The items below are what was checked on each agency's official pages, with dates.

• geoad.kr: measurement items and industry cases on the home page, the five steps on the process page, measured targets on the about page, 62 items and six areas on the free diagnosis page, the guide on finding a GEO agency. Viewed on October 9, 2026.
• zestcompany.co.kr: five operating items and the three-part GEO definition on the GEO service page, the three-month operating sequence and report cycle on the cost information page, more than 50 items on the free GEO check page, a Naver SEO menu. Viewed on October 9, 2026.
• summitfeed.co.kr: the eight-step operating order, seven industry tags, an article comparing hospital agencies. Viewed on October 9, 2026.
• intrix.kr: the three-cause split and three-step products on the GEO page, the number of questions and repeats on the cost information page, monthly contracts, monthly report items. Viewed on October 9, 2026.
• next-t.co.kr: three operating models, measured engines, GEO Score and free checks on the GEO page. Viewed on October 7, 2026.