# Overview

The Sentiment Analysis API provides additional speech insights by analyzing sentiments in a given transcript.

## API endpoint

The base URL for this version of the API is `https://api.rev.ai/sentiment_analysis/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.

## Sentiment scoring

The score in a sentiment analysis result represents the intensity or strength of the sentiment. It is not a confidence score. This score is always a value in the range [-1, 1]. A score below -0.3 indicates a negative (sad/angry) sentiment, while a score above 0.3 indicates a positive (joyful/happy) sentiment. Scores in the range [-0.3, 0.3] indicate neutral sentiment.

## Length limit

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