Welcome to the Base API v2 documentation.

The Base API lets you tap into Base and build your own Base-powered applications for the web, mobile or desktop.

Every API endpoint is built on top of our Service Oriented Architecture, which powers our web, mobile and desktop interfaces. This guarantees the quality of our API.

The API provides a simple, predictable, standardized, resource-oriented, RESTful interface with JSON-formatted responses to use Base’s features, including leads, contacts, deals, tags, notes, tasks, as well as filtering and searching.

We embrace built-in HTTP features, so our API is easily managed with off-the-shelf HTTP clients. Every request to the Base API can be easily performed using the curl command line tool.

The reference documentation is divided into four sections: API, OAuth 2, Getting Started and Resources


This section focuses on the most common elements of the API - the structure of requests and responses, error responses and rate limiting.

OAuth 2

The Base API uses industry-standard OAuth 2.0. This section explains which flows are supported and what you can achieve with each one, as well as what types of errors you can expect.

Getting Started

This is the best place to start when you’re ready to write your integration. You will learn how to make your first call and how to use the sandbox for testing.


Once you’re set up, you can browse through the reference library of resources and actions that we expose in the API. Each action is explained with possible parameters, sample requests and sample responses.


Your feedback does matter. Let us know what you want to see from the Base API.