Deep Research API for AI Agents: The Complete Guide (2026)

Deep research APIs automate multi-step research for AI agents, going beyond simple web searches. Unlike standard search APIs, they plan, execute multiple searches, and synthesize information, returning structured reports. While many options exist, they often rely solely on the web, limiting their data sources. Valyu offers a deep research API providing access to proprietary data from SEC filings, PubMed, and patents, setting it apart. Key features for evaluation include data source coverage, output formats, and pricing, with web-only APIs failing in scenarios needing proprietary data. Financial research, biomedical studies, and patent analysis are examples where web-only APIs fall short. Valyu's API allows developers to access proprietary sources. It offers various research modes and structured JSON output. Python and TypeScript code examples are included. A user interface is available for non-developers.