---
source_url: "https://docs.tavily.com/documentation/api-reference/introduction"
title: Introduction - Tavily Docs
mirrored_at: 2026-08-04T03:39:31.286Z
host: docs.tavily.com
cited_in_42a: true
mirror_canonical: "https://index.42a.ai/docs.tavily.com/documentation/api-reference/introduction"
---

> **Original source:** https://docs.tavily.com/documentation/api-reference/introduction

## Base URL

The base URL for all requests to the Tavily API is:

## Authentication

All Tavily endpoints are authenticated using API keys. [Get your free API key](https://app.tavily.com/).

## Endpoints

## Project Tracking

You can optionally attach a Project ID to your API requests to organize and track usage by project. This is useful when a single API key is used across multiple projects or applications. To attach a project to your request, add the `X-Project-ID` header:

**Key features:**

-   An API key can be associated with multiple projects
-   Filter requests by project in the [/logs endpoint](https://docs.tavily.com/documentation/api-reference/endpoint/usage) and platform usage dashboard
-   Helps organize and track where requests originate from

## Session Tracking

You can optionally include session and anonymized user identifiers in your API requests as HTTP headers. Tavily uses these identifiers for attribution and analytics across multi-step user interactions and agent workflows.

**Headers:**

-   `X-Session-Id` — opaque identifier for a session of related requests. Lets you group multiple calls together (e.g. all requests from one user task or conversation).
-   `X-Human-Id` — opaque identifier for the end-user behind the request. Useful when a single API key serves many human users — it helps Tavily better understand multi-step interactions and improve response quality. For security, Tavily hashes human IDs before processing or storing them.