Need help with your APIs? I offer API discovery, governance & evangelism services. Explore services →
API Evangelist API Evangelist
Discovery
Learnings
Guidance
Toolbox
Alignment
API Evangelist LLC
CircleCI website screenshot

CircleCI

CircleCI is a continuous integration and continuous delivery (CI/CD) platform that automates software build, test, and deployment pipelines. Their developer surface includes the REST API v2 (the recommended modern interface), the legacy v1 REST API, a Self-Hosted Runner API, webhooks for real-time event notifications, and the Orbs Registry of reusable configuration packages. Authentication is via a personal or project Circle-Token sent in the Circle-Token header; responses are JSON.

agent ready

Solid contracts, transparent operations, and an easy start — typically complete on four or five facets with one clear soft spot.

Kin Score

API Evangelist profiles CircleCI the way a machine reads it — 100 machine-readable artifacts across 18 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.

Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — CircleCI scores 64.4/100 (strong), with a separate agent-readiness read of 54/100 (agent ready). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.

Kin Score

This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.

Kin Score Kin Score How this is scored →
scored 2026-07-27 · rubric v0.5
Composite quality — 64.4/100 · strong
Contract Quality 18.0 / 25
Developer Ergonomics 7.0 / 20
Commercial Clarity 16.3 / 20
Operational Transparency 6.8 / 13
Governance 6.3 / 12
Discoverability 10.0 / 10
Agent readiness — 54/100 · agent ready
Machine-Readable Contract 18 / 18
Agentic Access Contract 15 / 15
MCP Server 0 / 12
Machine-Readable Auth 10 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 6 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3

How we profile CircleCI

Each block below is one kind of artifact we hold for CircleCI. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.

APIs 18

Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.

Individual APIs this provider publishes, each with its own machine-readable definition.

CircleCI Self-Hosted Runner API

The CircleCI Self-Hosted Runner API enables management and execution of jobs on self-hosted runner infrastructure. It provides endpoints for listing available runners, managing ...

CircleCI Webhooks

CircleCI Webhooks allow developers to receive real-time notifications about events in their CI/CD pipelines by configuring HTTP callbacks. Webhooks can be set up through project...

CircleCI Orbs Registry

CircleCI Orbs are shareable, reusable packages of CircleCI configuration that simplify build setup and integration with third-party tools. The Orbs Registry on the CircleCI Deve...

CircleCI Artifact API

Endpoints for listing and downloading build artifacts.

CircleCI Build API

Endpoints for retrieving build details, triggering builds, retrying builds, and canceling builds.

CircleCI Context API

Endpoints for managing contexts, which are used to secure and share environment variables across projects.

CircleCI Insights API

Endpoints for retrieving workflow and job metrics, summary data, and test performance insights.

CircleCI Job API

Endpoints for retrieving job details, artifacts, and test metadata associated with pipeline jobs.

CircleCI Pipeline API

Endpoints for triggering, retrieving, and managing pipelines and their configurations.

CircleCI Project API

Endpoints for listing followed projects and managing project settings.

CircleCI Resource Class API

Endpoints for managing runner resource classes, which define the compute resources available for self-hosted runner jobs.

CircleCI Runner Task API

Endpoints for querying task counts and managing tasks assigned to self-hosted runners.

CircleCI Schedule API

Endpoints for creating, updating, and managing scheduled pipeline triggers.

CircleCI SSH Key API

Endpoints for managing SSH keys and checkout keys for projects.

CircleCI Test Metadata API

Endpoints for retrieving test metadata collected during builds.

CircleCI User API

Endpoints for retrieving information about the authenticated user.

CircleCI Webhook API

Endpoints for creating, updating, listing, and deleting outbound webhook subscriptions.

CircleCI Workflow API

Endpoints for retrieving workflow details, managing workflow status, and rerunning workflows.

Scroll within the panel for all 18 ·

Open Collections 3

Open, tool-agnostic collections carry the same runnable value as Postman without locking you to one client — the portable, forkable form of the same exercise.

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

CircleCI REST API v1

OPEN COLLECTION

CircleCI REST API v2

OPEN COLLECTION

Pricing Plans 1

Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the six things the Kin Score reads for commercial clarity.

Published pricing tiers and plan structures.

Rate Limits 1

Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.

Documented rate limits and quota policies.

Circleci Rate Limits

4 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.

Cost, billing, and metering signals for API financial operations.

Features 16

The notable capabilities this provider advertises, captured as structured features so they can be searched and compared instead of read one landing page at a time.

Notable capabilities this provider offers.

Free: 30K credits/mo, 6K build minutes, 5 active users
Performance from $15/mo: 30K credits + $15/25K credits, 80x concurrency
Scale: custom annual, 200 GB storage, GPU, SSO, config policies
REST API v2 at circleci.com/api/v2
Default 3,000 req/min API rate limit
Self-hosted runners (Linux, Windows, macOS, Arm)
Docker layer caching (Performance+)
Orbs marketplace for reusable config
Webhooks for pipeline events
OAuth 2.0 + personal API tokens
Test splitting and parallel execution
GPU executors (Scale)
Insights API for build analytics
OIDC token federation for cloud auth
Config policies for governance (Scale)
SOC 2, FedRAMP Moderate (Scale)

Scroll within the panel for all 16 ·

Event Specifications 1

Not every API is request/response. AsyncAPI describes the event-driven and streaming side — the webhooks and channels — so the asynchronous half of the interface is documented the same way the synchronous half is.

AsyncAPI definitions for this provider's event-driven and streaming APIs.

CircleCI Webhooks

CircleCI Webhooks allow developers to receive real-time notifications about events in their CI/CD pipelines by configuring HTTP callbacks. Webhooks can be set up through project...

ASYNCAPI

Semantic Vocabularies 1

JSON-LD contexts give the data shared meaning across APIs. We profile them because semantics are what let a machine reconcile 'customer' here with 'customer' somewhere else.

JSON-LD contexts and semantic vocabularies used across these APIs.

Circleci Context

0 classes · 10 properties

JSON-LD

Spectral Rules 3

Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.

CircleCI API Rules

5 rules · 1 errors · 4 warnings

SPECTRAL

CircleCI API Rules

6 rules · 5 warnings

SPECTRAL

CircleCI API Rules

10 rules · 4 errors · 5 warnings

SPECTRAL

JSON Schema 49

Standalone JSON Schema definitions describe the data models behind the API. We profile them so the shapes are validatable on their own — useful long after a single request is forgotten.

Standalone JSON Schema definitions for this provider's data models.

Artifact

4 properties

JSON SCHEMA

ArtifactList

2 properties

JSON SCHEMA

Build

19 properties

JSON SCHEMA

BuildDetail

0 properties

JSON SCHEMA

BuildSummary

4 properties

JSON SCHEMA

CheckoutKey

6 properties

JSON SCHEMA

CheckoutKeyList

2 properties

JSON SCHEMA

Collaboration

5 properties

JSON SCHEMA

Context

3 properties

JSON SCHEMA

ContextList

2 properties

JSON SCHEMA

CreateContextRequest

2 properties

JSON SCHEMA

CreateScheduleRequest

5 properties

JSON SCHEMA

CreateWebhookRequest

6 properties

JSON SCHEMA

EnvironmentVariable

4 properties

JSON SCHEMA

EnvironmentVariableList

2 properties

JSON SCHEMA

ErrorResponse

1 properties

JSON SCHEMA

InsightsJobMetrics

2 properties

JSON SCHEMA

InsightsTestMetrics

4 properties

JSON SCHEMA

InsightsWorkflowMetrics

2 properties

JSON SCHEMA

InsightsWorkflowRuns

2 properties

JSON SCHEMA

Job

14 properties

JSON SCHEMA

MessageResponse

1 properties

JSON SCHEMA

CircleCI Pipeline

10 properties

JSON SCHEMA

PipelineConfig

4 properties

JSON SCHEMA

PipelineCreation

4 properties

JSON SCHEMA

PipelineList

2 properties

JSON SCHEMA

Project

5 properties

JSON SCHEMA

ProjectEnvVar

2 properties

JSON SCHEMA

ProjectEnvVarList

2 properties

JSON SCHEMA

RerunWorkflowResponse

1 properties

JSON SCHEMA

ResourceClass

3 properties

JSON SCHEMA

ResourceClassCreation

4 properties

JSON SCHEMA

Runner

10 properties

JSON SCHEMA

Schedule

9 properties

JSON SCHEMA

ScheduleList

2 properties

JSON SCHEMA

TestList

2 properties

JSON SCHEMA

TestMetadata

7 properties

JSON SCHEMA

Timetable

5 properties

JSON SCHEMA

TriggerPipelineRequest

3 properties

JSON SCHEMA

UpdateScheduleRequest

5 properties

JSON SCHEMA

UpdateWebhookRequest

5 properties

JSON SCHEMA

User

9 properties

JSON SCHEMA

CircleCI Webhook Event

9 properties

JSON SCHEMA

WebhookInfo

9 properties

JSON SCHEMA

WebhookList

2 properties

JSON SCHEMA

CircleCI Workflow

10 properties

JSON SCHEMA

WorkflowJob

8 properties

JSON SCHEMA

WorkflowJobList

2 properties

JSON SCHEMA

WorkflowList

2 properties

JSON SCHEMA

Scroll within the panel for all 49 ·

JSON Structure 1

JSON Structure captures the data shapes in a form built for tooling — a complement to JSON Schema that keeps the model machine-legible.

JSON Structure definitions describing this provider's data shapes.

Circleci Structure

0 properties

JSON STRUCTURE

Security Posture 4

Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Circleci Authentication

apiKey/http · 3 schemes

SECURITY

Circleci Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Circleci Vulnerability Disclosure

security.txt · contact published

SECURITY

Circleci Trust Center

SOC 2, FedRAMP, GDPR, CSA STAR

SECURITY

Agentic Access 1

An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.

Recommended x-agentic-access execution contracts for AI agents.

Circleci Agentic Access

74 operations · 30 acting

74 operations · 30 acting

AGENTIC

Resources

Every other property we hold for CircleCI — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.

Get Started 2

Portal, sign-up, and the first successful call

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

Build 1

SDKs, sample code, and the tooling you integrate with

Operate 2

Status, limits, changes, and where to get help

Commercial 2

Pricing, plans, and the legal terms of use

Company 3

The organization behind the API

← All providers · Data indexed from github.com/api-evangelist/circleci · machine-readable index on apis.io