# Overview

The Topic Extraction API provides additional speech insights by extracting a list of topics from a given transcript.

## API endpoint

The base URL for this version of the API is `https://api.rev.ai/topic_extraction/v1/`. All endpoints described in this documentation are relative to this base URL.

## Authentication

Clients must authenticate by including their [Rev AI access token](/api/security#access-token) in the `Authorization:` header of their requests. If the access token is invalid or the header is not present, a `401` error code will be returned.

## Length limit

Job submissions with input longer than 14000 words exceed our length restrictions and will fail.