Best AI Search & Retrieval APIs for startups
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Crail tracks 6 AI Search & Retrieval APIs vendors that list startups as a fit. These are the 5 that rank highest once the list is weighted for startups, and each one is shown with what it costs to start and whether you can start today without a contract — the facts that decide the shortlist at this size, rather than the same summary on every page.
How this list is weighted for startups
- 60% of the vendor's Crail agent-readiness score
- 15 points for a published free tier
- 15 points for being buyable self-serve, without a sales call
- up to 10 points for a low entry price (free tier, then a cheapest paid tier under $30, then under $75)
Startups and small businesses share the price-and-self-serve weighting; midmarket and enterprise share the compliance weighting. The full rules are on the methodology page.
Best overall: Exa
1. Exa80/100 agent-readiness
Search engine and API built for AI agents, offering semantic web search, content retrieval, and agentic research tools.
- Free tier: yes
- Open source: no
- Buy self-serve: yes
- Cheapest paid tier: Search at $7 (usage-based)
2. Brave Search API76/100 agent-readiness
Independent web index search API with Search and Answers plans, SOC 2 Type II attested, and an official MCP server for AI agents.
- Free tier: yes
- Open source: no
- Buy self-serve: yes
- Cheapest paid tier: Search at $5 (usage-based)
3. Serper59/100 agent-readiness
Low-cost, high-speed Google Search API (SERP data) for AI agents, RAG pipelines, and SEO tools, billed per-query with no subscription.
- Free tier: yes
- Open source: no
- Buy self-serve: yes
- Cheapest paid tier: Starter at $50 one-time
4. Perplexity Sonar API87/100 agent-readiness
Usage-based Sonar model API for real-time, citation-backed web search and Q&A, alongside standalone Search and Embeddings APIs.
- Free tier: no
- Open source: no
- Buy self-serve: yes
- Cheapest paid tier: Search API at $5 (usage-based)
5. Tavily79/100 agent-readiness
Search API built for AI agents, providing real-time web search, extraction, crawling, mapping, and research endpoints.
- Free tier: yes
- Open source: no
- Buy self-serve: no, sales call required
- Cheapest paid tier: no price published
FAQ
How is this AI Search & Retrieval APIs ranking calculated for startups?
This is not the raw agent-readiness leaderboard. Crail scores the 6 AI Search & Retrieval APIs vendors it tracks that fit startups, using 60% of the vendor's Crail agent-readiness score; 15 points for a published free tier; 15 points for being buyable self-serve, without a sales call; up to 10 points for a low entry price (free tier, then a cheapest paid tier under $30, then under $75). Exa ranks first once the startups weighting is applied, even though Perplexity Sonar API scores higher on raw agent-readiness (87/100 against Exa's 80/100), because the weighting adds points that score does not cover.
Which of these can a startup use without paying?
4 of the 5 publish a free tier: Exa, Brave Search API, Serper and Tavily. None of them are open source.
Do any of them require a sales call before you can buy?
Tavily requires a sales call before you can buy. Exa, Brave Search API, Serper and Perplexity Sonar API do not.