API v2 Introduction

The CircleCI API may be used to make API calls to retrieve detailed information about users, jobs, workflows and pipelines. There are currently two supported API versions:

• API v1.1 Reference
• API v2 Reference

API v2 includes several powerful features (e.g. support for pipelines and pipeline parameters) that are unavailable in API v1.1. It is recommended that CircleCI cloud users migrate their scripts to API v2 stable endpoints as soon as possible.

CircleCI API v1.1 and v2 are supported and generally available. CircleCI expects to eventually End-Of-Life (EOL) API v1.1 in favor of API v2. Further guidance on when CircleCI API v1.1 will be discontinued will be communicated at a future date.

CircleCI API v2 enables you to use endpoints with several new features that improve the API experience, in addition to optimizing how you use the API for your jobs.

The current categories of the API v2 endpoints are:

• Authentication
• Context
• Insights
• User
• Pipeline
• Job
• Workflow
• Webhook
• Project
• Schedule

The CircleCI API v2 is backwards-compatible with previous API versions in the way it identifies your projects using repository name. For instance, if you want to pull information from CircleCI about the GitHub repository https://github.com/CircleCI-Public/circleci-cli you can refer to that in the CircleCI API as gh/CircleCI-Public/circleci-cli, which is a “triplet” of the VCS type, the name of your “organization”, and the name of the repository. For the VCS type you can use github or bitbucket as well as the shorter forms gh or bb, which are now supported in API v2. The organization is your username or organization name in your version control system.

With API v2, CircleCI is introducing a string representation of the triplet called the project_slug, which takes the following form:

<vcs_type>/<org_name>/<repo_name>

The project_slug is included in the payload when pulling information about a project as well as when looking up a pipeline or workflow by ID. The project_slug can then be used to get information about the project. It is possible in the future the shape of a project_slug may change, but for GitHub and Bitbucket projects it is currently usable as a human-readable identifier for a given project.

The CircleCI API v2 enables users to be authenticated by sending your Personal API token as a HTTP header in the request, with the name Circle-Token and the token as the value. You can find examples in the API Developer’s Guide.

Here is a simple example using curl to trigger a pipeline with parameters:

curl -X POST --header "Content-Type: application/json" --header "Circle-Token: $CIRCLE_TOKEN" -d '{
  "parameters": {
    "myparam": "./myspecialdir",
    "myspecialversion": "4.8.2"
  }
}' https://circleci.com/api/v2/project/{project_slug}/pipeline

In the above example the project_slug would take the form :vcs/:org/:project. For example, the project slug gh/CircleCI-Public/circleci-cli tells CircleCI to use the project found in the GitHub organization CircleCI-Public in the repository named circleci-cli.

IMPORTANT Pipeline parameters are not treated as sensitive data and must not be used for sensitive values (secrets). You can find information on using sensitive data correctly in the Security overview and Contexts guides.

The CircleCI API v2 release includes several new endpoints, and deprecates some others. The sections below list the endpoints added for this release, in addition to the endpoints that have been removed.

For a complete list of all API v2 endpoints, please refer to the API v2 Reference Guide, which contains a detailed description of each individual endpoint, as well as information on required and optional parameters, HTTP status and error codes, and code samples you may use in your workflows.

The table below describes the new endpoints that have been added to the CircleCI API for this updated v2 version.

With API v2, several endpoints from v1 have been deprecated, which are listed in the table below.

API v2 is not supported for installations of CircleCI server 2.x. API v2 is supported for self-hosted installations of CircleCI server 3.x.

• Review the API Developer’s Guide for a detailed walkthrough on authenticating as well as example API requests.