This is a comparison of web search APIs (SERP APIs) for LLM-based AI agents.

Why Use a Search API With an AI Agent?

You may need a web search API if you’re building an AI agent and want it to be able to search for information on the web.

How Do AI Agents Use Web Search APIs?

If you’re developing an AI agent, you’ll typically want it to make use of web search APIs through functionality baked into LLMs known as ‘tool-calling’, ‘tool-use’ or ‘function-calling’.

Frameworks such as LangChain have support for tool-/function-calling and have off-the-shelf integrations with some of the APIs (e.g. this one for Tavily and this one for If an integration isn’t already available, it’s typically fairly simple to build one.

Web Search API Pricing

NameFree TierLowest-Volume Paid TierLowest Advertised Cost*
(at Scale)
Serper2500 calls$50 (valid for 6 months)0.03¢/callLangChain integration
Tavily1000 calls/month$100/month0.6¢/callLimited to 20 calls/minute
YOU1000 calls/month
for 60 days
Brave2000 calls/month
1 call/second
$5 CPM
* Bespoke pricing may be available for high volumes.

What to Consider When Choosing a Web Search API

  1. Relevance of search results – different services use different search engines to retrieve their results. Just as you may prefer Google search over Bing search when you’re searching manually, you prefer the results from one web search API over those from another.
  2. Content of each search result – different services return different information for each search result and this can have a big impact on the effectiveness of your agent. You may, for example, prefer services that include relatively long snippets of content.
  3. Pricing – unsurprisingly, different services have different prices. Note that some services have optional parameters that can significantly impact pricing, e.g. doubling the effective cost of requests.
  4. Other terms and conditions – depending on the nature of your business, factors such as the providers’ privacy policies may be very important.