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Merit-only ranking · 7 providers · one corpus

Best AI Answer & Research API

Cited-answer and research endpoints ranked on correctness, citation faithfulness, latency and cost — the ones that ground an agent instead of hallucinating.

Every score comes from the Auxiliar curator fleet running each provider on the same corpus — so this is a merit-only ranking, not a listicle. Exa takes the top spot (correctness 1.00, $0.005 / call). Full table below — and because Auxiliar resells all of them, you can try the winner (or route between several) on one API key without a new signup.

The ranking

Ranked by composite score. Each row links to the provider's full scorecard.

1 ExaTop pick You want semantic discovery, 'find similar', research, or a built-in /answer endpoint. 7.9/10 Correctness 1.00 $0.005 / call 2 You.com You want an independent index with soft domain-boosting and a cited Research API. 7.79/10 Correctness 1.00 $0.02 / call 3 Parallel You want the lowest-friction in-loop option — a no-key Search MCP and sub-second P50. 7.58/10 Correctness 1.00 $0.01 / call 4 Tavily You want the agent/RAG default that returns a relevance score and optional answer in one call. 7.13/10 Correctness 1.00 $0.008 / call 5 Brave Search You want an index that isn't a Google/Bing scrape, plus a privacy posture and AI grounding. 7.02/10 Correctness 1.00 $0.06 / call 6 Linkup You want a compliant SERP alternative with a built-in sourced answer and structured JSON. 6.91/10 Correctness 1.00 $0.005 / call 7 Jina You want clean LLM-ready markdown from a URL or a search-plus-read in a single call. 6.61/10 Correctness 1.00 $0.02 / call

One key. Every provider on this page.

Stop juggling signups and invoices. One Auxiliar API key calls all of them — upstream keys injected server-side, usage billed to a single balance. Swap the base URL and go.

curl https://api.auxiliar.ai/serper/search \
  -H "Authorization: Bearer $AUXILIAR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"q": "latest ai agent news"}'
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