Best search API for RAG pipelines (2026)
RAG pipelines make a lot of search calls — sometimes hundreds per user session. Choosing the wrong engine means paying Exa prices ($7/1k) for queries Serper handles equally well at $1/1k. We benchmarked 170 real agent queries across 6APIs. Here's what to use for each retrieval pattern, and how to route across all of them.
RAG retrieval patterns — which engine wins
| Retrieval pattern | Best engine | Why |
|---|---|---|
| Academic / technical papers | Exa | Semantic search, academic index depth |
| Real-time news | Serper | Cheapest web/news at $1/1k; Brave at $5/1k also strong |
| Page content extraction | Firecrawl | Cheapest page scrape at $0.85/1k |
| Cited answer synthesis | Perplexity | Answer-shaped with citations (cost: $5/1k, quality not measured in v1) |
| General web lookup | Serper or Brave | Cheapest options; Brave has independent index |
| Mixed / unknown | Route per class | No single engine wins all patterns — use GroundRoute to route |
Rankings based on GroundRoute benchmark, N=170 queries. Quality is indicative (small per-class n). Full methodology →
Tavily vs Exa for RAG — the honest comparison
Tavily ($8/1k) is the default in LangChain and LlamaIndex RAG tutorials — it packages search + scrape + rank in one call, which is convenient. Exa ($7/1k) is stronger for academic and semantic retrieval. Both are expensive for high-volume RAG. In our benchmark, Firecrawl ($0.85/1k) and Serper ($1/1k) matched quality on web/news/page classes at a fraction of the cost.
How to route search for RAG — one endpoint, 6 engines
GroundRoute routes each retrieval call to the cheapest engine that clears the quality bar for that query class — academic to Exa/Firecrawl, web/news to Serper, page content to Firecrawl. Repeated queries are cached so they cost nothing on re-runs. You keep ~half the cache savings.
Related
FAQ
- What is the best search API for RAG?
- It depends on your document mix. For academic papers and technical content, Exa's semantic search leads. For real-time news and web content, Serper ($1/1k) is cheapest. For page content extraction, Firecrawl ($0.85/1k) is best. Most RAG pipelines mix these — route per query class.
- Should I use Tavily or Exa for RAG?
- Tavily is designed for RAG (search + scrape + rank in one call) and is a LangChain/LlamaIndex default. Exa is stronger for academic and semantic retrieval. Tavily ($8/1k) and Exa ($7/1k) are both expensive — for many RAG queries, Serper ($1/1k) or Brave ($5/1k) matches quality at lower cost. Route per class.
- How do I add web search to a RAG pipeline?
- Call a search API in your retrieval step. GroundRoute gives you one endpoint for 6 engines — route per query class, cache repeats. Works with LangChain, LlamaIndex, or any Python/JS HTTP call.
- Is Tavily free?
- Tavily offers 1,000 free searches/month. After that, $8/1k at list price. GroundRoute's gain-share model means you keep ~half the cache savings — so repeated RAG queries get cheaper over time.