The Tools section of the Quantopian User Guide provides high level explanations of the various tools available for you to use on Quantopian. Descriptions include an overview of the tool, when and why you might want to use it, and links to resources to learn how to use it. The user guide covers each of the following tools on Quantopian:

Pipeline is a tool designed to make it easy to define and execute cross-sectional trailing-window computations. Pipeline is Quantopian's core tool and learning how to use it is the best way to become a Quantopian expert.
Alphalens is a tool for analyzing the efficacy of alpha factors.
Optimize is a tool that provides structured methods for solving portfolio optimization problems.
Algorithm API
The Algorithm API provides you with functions you can use to build an algorithm for backtesting.
Pyfolio is a tool for generating an in-depth analysis of a backtest.
Research API
The Research API provides structured methods unique to Quantopian that assist you with querying data and analyzing backtest results.
Risk Model
The Risk Model gives you insight into the financial risk factors of a strategy or signal.
Self-Serve Data
Self-Serve Data is a tool for uploading custom datasets to Quantopian.