The API serves ChatGPT, Gemini, Perplexity, Copilot, Grok, Google AI Mode, Google Search, and Google News. Each engine has its own endpoint and its own
response schema; the shared parts (text, sources) have the same names everywhere. This page
lists what each served engine accepts and returns, and which fields come back empty on the answers served today.
Include flags
Flags go in include and add fields to the result. A flag an engine doesn't list is rejected as an unknown field.
An empty field stays in the schema with its type, so code written against it keeps working. On ChatGPT the brands an
answer names are in text and entities. Today's answers show no merchant cards, so
shoppingCards comes back empty, even with include.shopping.
Country lists per engine are also returned by GET /v1/countries?model=<engine>. See coverage.
Answer depth
Every engine writes one depth of answer. Perplexity answers every request with its Quick Search answer: one search
and a short answer of a few sentences. answerDepth (any, full or
quick) is accepted so existing requests stay valid, and it does not change the answer or the price.