Getting started with Circle

Circle allows developers to easily integrate unrivaled security, identity authentication and privacy protection capabilities into their applications as a single unified API, which is industry-first.  We ourselves are learning more each day about new things that can be done with Circle’s remarkable architecture.   

Circle integration options

Circle supports 2 easy integration options that address both Web and Device Native Applications to provide your users with uncompromised security, privacy.

  • SDKs and Libraries

Circle API

  • For Web Sites and Applications
  • Easy & rapid implementation, effortless maintenance. You'll be up and running in a few hours.
  • Requires download of lightweight thin clients that address on-device functionalities for encryption, key management, authentication and other functionalities that uniquely protect identity, data and privacy.

Circle API currently has two separate method libraries. These will be unified in our near-term roadmap, but already work together.


Getting Started with REST API

Circle Access API

Getting Started with Circle Access API


Modules for our REST APIs that make integration even simpler and faster. WordPress, Passport, WikiJS are available and more to come.

Check out our Github


Getting Started with Circle SDK

  • Lightweight libraries
  • Inline & rapid implementation
  • Fully integrated with your applications

What Circle REST API does and how it is different

Circle REST API's primary focus and functionalities are in these areas:

  • Creation and formation of cryptographically defined secure private networks called Circles.
  • Spoof-proof out-of-band distributed P2P authentication to create them.
  • Client-side E2EE encryption and protection of data in AES 256 encrypted Secure Capsules.
  • Encryption key management and protection.
  • Data owner control of encryption keys and thus control of privacy of identity and data.

Circle REST API is fundamentally different than most traditional APIs you have worked with. This is because you only reach out to the Circle cloud one time, to get an authentication token.  After that you communicate with the Circle Service running on your local machine.

For example, the endpoint to get a Bearer Token is https://api.circlesecurity.ai/api/token. But to enumerate items in the Circle you call

The reason for this is Circle keeps keys on the local machine and not in the cloud.  So those cannot be sent to the cloud.  This is the whole premise upon which the security of the system is built.

Now, you could do all the subsequent API calls using REST calls to localhost. In order to make things even easier for Web site and application developers, we have created a Javascript SDK with NodeJS SDK objects that are super simple to use.   

The code samples below use REST to get the token then the NodeJS SDK for further API calls.

Learn more

We recommend that the developer spend a few minutes in our Learning Center to understand some of the basic concepts of the platform architecture and components that powers the Circle REST API.

Circle Access API is 'Traditional' REST

The concepts and architecture of the Circle Access API are those of a traditional REST API. It's primary focus and functionalities are in these areas:

  • Codeless credential free multi-factor authentication.
  • Continuous Authentication
  • Authorization and Approval workflows.

How Circle Access API relates to Circle REST API

A unique and powerful aspect of Circle Access API is how it works together with:

  1. Circle Access Mobile Application. This is like an authenticator but goes way beyond that. Your Smartphone is your password - with cryptographic binding of unique keys and biometric verification of the end user.
  2. Circle Access Desktop. This is an ultra-light thin client that runs as a service on PC and Workstations. Circle Access Mobile can securely communicate, make calls and synchronize data with the Circle Access Desktop. This means that all the data security and privacy protections, and unique out-of-band P2P authentication method, of Circle REST API are fully integrated with and accessible to Circle Access Mobile.

In our near term roadmap, these APIs will be unified.

Use Cases

We ourselves are learning more each day about new things that can be done with Circle’s remarkable architecture. These are the areas of functionality that are available for developers to develop and implement with Circle API that we know of today. Over the next months and years, we will continue to expand both its capabilities and ease of use as we work with you. 

Those which have emerged over the course of our work with partners and customers in our Early Access program are outlined here:

There are other major use cases that we know that we will release API products and solutions for soon.

API Products

Our product structure reflects what we have learned about these use cases, and how to best explain and present the different capabilities of Circle API. You can find direct links to each of them here:

Getting Started Guides

Please refer to our Getting Started Guides, which can help you get integrations up and running in a few hours! They are organized by API product.