langsearch

langsearch

LangSearch provides a free web Search API and a free Rerank API that deliver natural-language search over billions of web documents and a semantic reranker optimized for LLM applications and AI agents.

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Freemium API Enterprise 75/100
#496 in AI Agents (496 tools)
Just launched
Data reviewed Aug 28, 2026

Profile facts come from the vendor source. AiMatch labels unknown pricing or API details instead of estimating them.

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Quick Overview

Best for: AI Agents

What it does

AI Agents software for decision-makers comparing workflow fit and alternatives.

Best fit

AI Agents

Pricing snapshot

Freemium from Free (no credit card required)

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langsearch

LangSearch is a provider of web search and semantic reranking APIs designed for LLM-driven applications and AI agents. The service offers a Web Search API that supports natural language queries across billions of web documents (including news, images, and videos) and a separate Rerank API driven by a transformer-based LangSearch reranker. The platform emphasizes delivering clean, accurate, high-quality context for LLM applications, with tooling and integrations for direct API calls, LLM function calls, LangChain examples, and AI agent plugins. LangSearch offers a free tier and positions itself for integration into AI search, chatbots, retrieval-augmented generation (RAG), and other production workflows.

Web search and rerank API for LLM applications, providing accurate context.

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Key Features

Natural Language Web Search API

A Web Search API supporting natural language search across billions of web documents, including news, images, videos, and more.

Free Rerank API

A semantic rerank API (langsearch-ranker) to boost search result accuracy; described on the site as 'Absolutely Free, No credit card required.'

Hybrid search & semantic reranker

Support for mixed keyword and vector searches using a hybrid search database and semantic reranker to improve relevance.

Lightweight transformer reranker

LangSearch Rerank model based on transformer architecture that achieves ranking performance comparable to 280M–560M models while using ~80M parameters for faster inference and lower cost.

Easy integration with LLM tooling

Direct API integration plus examples and mentions of using LangSearch via LLM function calls, LangChain, and AI agent plugins.

API options: freshness, summary, count

The API example demonstrates request parameters such as 'freshness', 'summary', and 'count' to control results and summaries.

Pricing

Free Tier Available

Free access to the Web Search API and Rerank API for evaluation; the site repeatedly advertises 'TRY FREE' and 'Absolutely Free, No credit card required.'

Free

Free (no credit card required)
  • Access to Web Search API and Rerank API to try for free
  • Basic API usage for evaluation

Use Cases

LLM augmentation and RAG

Provide web context and high-quality search results to retrieval-augmented generation (RAG) systems and LLMs.

AI Agents and Chatbots

Integrate search and reranking into AI agents and chatbots to enable up-to-date and relevant responses from live web content.

Custom search workflows

Call the LangSearch API from custom applications or workflows with filtering options and hybrid (keyword/vector) search support.

Integrations

LangChain

Site includes a LangChain example showing how to call LangSearch from a LangChain workflow and use function calls.

LLM tools & AI agent plugins

Described integration paths for LLM function calls, agent plugins, and embedding the API into AI agents, chatbots, and RAG systems.

Benefits

Delivers clean, accurate, high-quality web context for LLMs and AI agents.
Lower inference cost and faster performance using a compact (~80M parameter) reranker with results comparable to much larger models.
Free tier available with no credit card required to try the Web Search API and Rerank API.
Flexible integration options including direct API calls, LLM function calls, LangChain examples, and agent plugins.

Limitations

No explicit rate limit or quota information is provided on the supplied page.
No detailed paid pricing tiers or usage-based pricing breakdown shown on the supplied page.

Frequently Asked Questions

No verified FAQs are available.

Getting Started

  1. 1 Step 1: Visit the LangSearch site and sign up or click 'START FOR FREE' (no credit card required).
  2. 2 Step 2: Retrieve an API key and review the API example (curl example for 'https://api.langsearch.com/v1/web-search' is provided on the page).
  3. 3 Step 3: Integrate with your application or LLM toolchain (examples show LangChain and LLM function call usage) and call the Web Search or Rerank endpoints with parameters like 'query', 'freshness', and 'summary'.

Support

docs

The site lists 'DOCS' / Documentation as a resource for API usage and examples (documentation label present on the site).

site pages

Site includes legal and informational pages (Privacy Policy, Terms of Service) and product pages for Database, Reranker, API, and Docs.

API

Available: Yes
Documentation:

Documentation and example API usage are linked or shown on the site (page includes a curl example and a JSON response example), exact documentation URL not provided in supplied content.

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