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What the ChatGPT API misses

Run a query through ChatGPT's API and through what real users see in the ChatGPT UI. See how the brand mentions, citations, and rankings differ. Most teams optimize for the API answer. Their customers see the UI answer. The gap between them is your blind spot.

The gap, illustrated

Three places the API answer drifts

Same prompt. Same brand. Different answers depending on where you ask.

Citations

The API returns a clean answer with structured sources. The UI cites a different set of URLs because the UI is doing live web search; the API is reading from training cutoff plus tool-use traces. Your blog post may rank in one and vanish from the other.

Brand prominence

"Best CRM for startups" surfaces Notion in the API answer at rank 3 and the UI answer at rank 7. Same model, same query. The difference is the UI's grounding model and the API's RAG path. Both are real customer experiences. You need to track both.

Fan-out queries

The UI quietly expands a prompt into 3-7 sub-queries before answering. The API doesn't show you those sub-queries. That fan-out is where most of your SEO investment has to land. If you can't see it, you can't optimize for it.

How the report runs

One call. Five UI scrapes. Statistical confidence.

Built on /v1/check mode=deep. The same primitive every paying customer uses.

  1. Hit the four LLM APIs in parallel

    ChatGPT, Claude, Gemini, Perplexity — straight from their official APIs. This is the answer your code sees today.

  2. Run the same query through each UI five times

    Live UI scrapes via our dedicated browser-based scraping infrastructure. Five runs lets us bound the variance — the same UI answer can shift across runs even at temperature zero.

  3. Compute the API-vs-UI delta with confidence intervals

    Wilson 95% confidence on mention rate, bootstrap CI on rank distributions. Numbers come with error bars or they don't ship.

  4. Report what's different

    Brand mentions on each side, missing citations, fan-out sub-queries the API never surfaced, rank movement across runs.

Why this is a free tool

Most GEO tools sell vibes. We let you measure the gap before you pay us anything.

The API-vs-UI delta is the single most counterintuitive measurement in AI-search optimization. It's also the one that decides whether your investment in content actually shows up where customers see it. Running this once on your own brand answers the question better than any sales pitch we could write.

If the delta is small, you don't need us. If the delta is big, you do. Either way you saved a meeting.

The API-vs-UI delta is one /v1/check call away.

Sign up — $2 of credit lands in your wallet. That's enough for one deep-mode run on your top query plus a few quick checks on the side. No card required.