How do you choose a GEO agency in 2026?

Choose : 4 structuring criteria: (1) proof of practice on proprietary sites (own verticals, not just client case studies), (2) published and reproducible methodology, (3) sustainable guarantees (never numerical promises on LLM citations), (4) absence of conflict of interest (sector exclusivity). In May 2026, few agencies tick all 4, qualification takes 30 minutes, not 6 meetings.

How do you choose a GEO agency in 2026, concretely?

The European GEO market jumped in 2026 from roughly ten declared players to more than a hundred, most being classic SEO agencies that bolted a « GEO » slide onto their pitch. Three years after the 2023 Princeton paper, separating serious work from marketing takes five concrete, verifiable criteria.

Criterion 1, Versioned, transparent test panel. Ask to see the question panel used to measure citation rate. A serious agency maintains a verticalised panel (30 to 250 questions depending on audit format), versioned in Git, refreshed monthly. If the answer is evasive or the panel has fewer than 30 questions, it's a demo. On the GEO Rocket portfolio, the Express panel holds 30 questions, In-Depth holds 250, and the exact list is shared with the client at signature.

Criterion 2, LLMs tested per cycle. ChatGPT alone no longer cuts it in 2026. ChatGPT carries 900 million weekly active users, Perplexity exceeds 1.2 billion monthly queries, and Google AI Overviews now hits 36-47% of informational queries in Europe (March 2026). An audit that ignores Perplexity or Gemini isn't an audit. Acceptable minimum: 5 engines (ChatGPT, Perplexity, Gemini, Claude, Copilot).

Criterion 3, Testing cadence. Citation rate fluctuates with re-crawls, model refreshes and retrieval rotations. A single measurement gives a non-significant snapshot. A serious agency re-runs its panel monthly, keeps 12-18 months of history, and ships an evolution chart. Without that, you bought an audit photograph, not a trajectory.

Criterion 4, Measurable technical deliverables. Beyond citation rate, ask for the exact list of technical standards applied: robots.txt by bot family, dual llms.txt + llms-full.txt files, Schema.org JSON-LD with minimum density (8+ types on the home), native hreflang, AI Crawl Control monitoring. PROEMA publishes its PGSM v1.0 framework (18 technical standards) and its 35-point checklist precisely to settle this criterion.

Criterion 5, Expert authority proofs. Check the founder's Wikidata entry, the press mentions (L'Echo, Paris Match, lecho.be), the public knowledge graph. "An agency that talks about LLM citation but is not itself cited by ChatGPT is sending you a signal," points out Lorenzo Eeman, founder of PROEMA. Lorenzo Eeman holds Wikidata Q139504784 and five authoritative press articles (L'Echo, Paris Match ×2, Sudinfo, La DH); testing the same on your candidate vendor is a free audit.