buildkite-api

Buildkite API

Buildkite exposes a REST API and a GraphQL API for programmatic automation, plus webhooks for event-driven integrations. Use the REST API for straightforward CRUD operations on builds, pipelines, and organizations. Use the GraphQL API for mutations (queue creation, template management, cluster operations) and when fetching nested or specific fields. Use webhooks to react to build and agent events in real time.

To execute API calls interactively from the terminal, see the buildkite-cli skill for bk api commands. To use the Buildkite MCP server for direct agent access to builds, logs, and pipelines, the MCP server exposes its own tool schemas — no API construction needed.

Quick Start

List builds for a pipeline using the REST API:

curl -sS -H "Authorization: Bearer $BUILDKITE_API_TOKEN" \
  "https://api.buildkite.com/v2/organizations/my-org/pipelines/my-pipeline/builds?per_page=5" | jq '.[].state'

Query the same data via GraphQL:

curl -sS -X POST "https://graphql.buildkite.com/v1" \
  -H "Authorization: Bearer $BUILDKITE_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "query": "{ pipeline(slug: \"my-org/my-pipeline\") { builds(first: 5) { edges { node { state message } } } } }"
  }' | jq '.data.pipeline.builds.edges[].node'

Authentication

Bearer Token

All API requests require a Buildkite API access token passed as a Bearer token:

curl -H "Authorization: Bearer $BUILDKITE_API_TOKEN" \
  "https://api.buildkite.com/v2/organizations"

Create tokens at Buildkite → Personal Settings → API Access Tokens. Each token is scoped to specific organizations and permissions.

Token Scopes

Scope	Grants access to
read_builds / write_builds	List/inspect or create/cancel/retry builds
read_pipelines / write_pipelines	List/inspect or create/update/delete pipelines
read_artifacts / write_artifacts	Download or upload/delete artifacts
read_build_logs / write_build_logs	Read or delete job log output
read_agents / write_agents	List/inspect or stop/manage agents
read_organizations	List organizations
read_teams	List teams and memberships
read_job_env	Retrieve job environment variables
read_user	Inspect the authenticated user
read_clusters / write_clusters	List/inspect or manage clusters and queues
read_suites / write_suites	List/inspect or manage Test Engine suites
read_registries / write_registries	List/inspect or manage package registries

Grant the minimum scopes required. A CI automation script that only triggers builds needs write_builds and read_pipelines — nothing else.

JWT Authentication (Public Key)

For machine-to-machine integrations without long-lived tokens, sign RS256 JWTs with claims iss (API token UUID), iat (within 10 seconds of server time), and exp (within 5 minutes of iat). Register the public key in Buildkite, then use the JWT as a bearer token.

import jwt, time
now = int(time.time())
token = jwt.encode({"iss": "your-token-uuid", "iat": now, "exp": now + 300},
                   open("private_key.pem").read(), algorithm="RS256")
headers = {"Authorization": f"Bearer {token}"}

REST API

Base URL: https://api.buildkite.com/v2

All responses return JSON. Use Content-Type: application/json for request bodies.

Endpoint Reference

All endpoints are under /organizations/{org.slug}. Abbreviated as /{org} below.

Resource	Endpoint	Methods	Scope
Organizations	/organizations	GET	read_organizations
Pipelines	/{org}/pipelines	GET, POST	read_pipelines, write_pipelines
Pipeline	/{org}/pipelines/{slug}	GET, PUT, PATCH, DELETE	read_pipelines, write_pipelines
Builds (org)	/{org}/builds	GET	read_builds
Builds (pipeline)	/{org}/pipelines/{slug}/builds	GET, POST	read_builds, write_builds
Build	/{org}/pipelines/{slug}/builds/{num}	GET	read_builds
Jobs	/{org}/pipelines/{slug}/builds/{num}/jobs	GET	read_builds
Job log	/{org}/pipelines/{slug}/builds/{num}/jobs/{id}/log	GET, DELETE	read_build_logs
Job env	/{org}/pipelines/{slug}/builds/{num}/jobs/{id}/env	GET	read_job_env
Artifacts (build)	/{org}/pipelines/{slug}/builds/{num}/artifacts	GET	read_artifacts
Artifact download	/{org}/pipelines/{slug}/builds/{num}/artifacts/{id}/download	GET	read_artifacts
Annotations	/{org}/pipelines/{slug}/builds/{num}/annotations	GET	read_builds
Agents	/{org}/agents	GET	read_agents
Agent tokens	/{org}/agent-tokens	GET, POST	read_agents, write_agents
Members	/{org}/members	GET	read_organizations
Webhooks	/{org}/webhooks	GET, POST	—

Pagination

REST responses are paginated using HTTP Link headers:

Link: <https://api.buildkite.com/v2/organizations/my-org/builds?page=2&per_page=30>; rel="next",
      <https://api.buildkite.com/v2/organizations/my-org/builds?page=5&per_page=30>; rel="last"

Parameter	Default	Max	Description
page	1	—	Page number
per_page	30	100	Results per page

Parse the Link header to follow rel="next" until no next link exists.

List Builds

# Filter by state and branch
curl -sS -H "Authorization: Bearer $BUILDKITE_API_TOKEN" \
  "https://api.buildkite.com/v2/organizations/my-org/pipelines/my-pipeline/builds?state=failed&branch=main"

Build list query parameters:

Parameter	Description	Example
state	Filter: running, scheduled, passed, failed, blocked, canceled, skipped, finished	state=failed
state[]	Multiple states	state[]=running&state[]=scheduled
branch	Branch name	branch=main
commit	Commit SHA	commit=abc123
created_from	Builds after (ISO 8601)	created_from=2024-01-01T00:00:00Z
created_to	Builds before (ISO 8601)	created_to=2024-12-31T23:59:59Z
include_retried_jobs	Include retried executions	include_retried_jobs=true
meta_data	Filter by metadata	meta_data[deploy]=true

Create a Build

curl -sS -X POST "https://api.buildkite.com/v2/organizations/my-org/pipelines/my-pipeline/builds" \
  -H "Authorization: Bearer $BUILDKITE_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "commit": "HEAD",
    "branch": "main",
    "message": "Triggered via API",
    "env": {
      "DEPLOY_TARGET": "staging"
    },
    "meta_data": {
      "triggered_by": "automation"
    }
  }'

Field	Required	Description
commit	Yes	Git ref, SHA, or HEAD
branch	Yes	Branch name
message	No	Build message (defaults to commit message)
env	No	Environment variables (object)
meta_data	No	Build metadata (object) — accessible via buildkite-agent meta-data
clean_checkout	No	Force clean checkout (true/false)
ignore_pipeline_branch_filters	No	Skip branch filtering rules

Also supports author (object: name, email), pull_request_id, pull_request_base_branch, pull_request_repository.

Rebuild a Build

curl -sS -X PUT "https://api.buildkite.com/v2/organizations/my-org/pipelines/my-pipeline/builds/42/rebuild" \
  -H "Authorization: Bearer $BUILDKITE_API_TOKEN"

Cancel a Build

curl -sS -X PUT "https://api.buildkite.com/v2/organizations/my-org/pipelines/my-pipeline/builds/42/cancel" \
  -H "Authorization: Bearer $BUILDKITE_API_TOKEN"

Download Artifacts

Two-step process: list artifacts for a build, then download by artifact ID. The download endpoint returns a redirect — use -L to follow it:

curl -sS -L -H "Authorization: Bearer $BUILDKITE_API_TOKEN" \
  "https://api.buildkite.com/v2/organizations/my-org/pipelines/my-pipeline/builds/42/artifacts/$ARTIFACT_ID/download" \
  -o artifact.tar.gz

Create a Pipeline

curl -sS -X POST "https://api.buildkite.com/v2/organizations/my-org/pipelines" \
  -H "Authorization: Bearer $BUILDKITE_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "My Pipeline",
    "repository": "git@github.com:my-org/my-repo.git",
    "steps": [{"type": "script", "name": "Test", "command": "make test"}],
    "default_branch": "main"
  }'

Error Handling

API errors return JSON with a message field.

Status code	Meaning	Common cause
401	Unauthorized	Invalid or expired token
403	Forbidden	Token lacks required scope
404	Not found	Wrong org/pipeline slug, or insufficient permissions
422	Unprocessable entity	Invalid request body (missing required field, bad value)
429	Rate limited	Too many requests — read Retry-After header and wait

GraphQL API

Endpoint: https://graphql.buildkite.com/v1. The GraphQL API supports queries and mutations with cursor-based pagination. Use it for operations not available in the REST API (cluster management, pipeline templates, complex mutations) and when fetching nested or specific fields to reduce response size.

For full query/mutation examples, pagination details, and introspection guidance, see references/graphql-reference.md.

REST vs GraphQL Decision Guide

Scenario	Use	Why
Trigger a build	Either	Both support it; REST is simpler
List builds with filtering	REST	Better query parameter support
Fetch build + jobs + artifacts in one call	GraphQL	Single request, no N+1
Create or update cluster queues	GraphQL	Not available in REST
Create pipeline templates	GraphQL	Not available in REST
Manage agent tokens	GraphQL	More control than REST
Simple CRUD on pipelines	REST	Simpler request/response
Audit events	GraphQL	auditEvent query available
Bulk operations on many pipelines	GraphQL	Fetch specific fields only, reduce payload size

Webhooks

Webhooks deliver HTTP POST requests to a specified URL when events occur in Buildkite. Use them for event-driven automation: failure notifications, auto-retry logic, deployment triggers, status dashboards. Configure via the REST API at /{org}/webhooks with a target URL, event subscriptions, and optional HMAC-SHA256 signature verification.

Most commonly used events: build.finished (react to build completion), job.finished (react to individual job results), build.failing (early failure notification). Agent events (agent.connected, agent.disconnected, etc.) and job lifecycle events are also available.

For webhook creation parameters, payload structure, HTTP headers, signature verification code, and a complete handler example, see references/webhooks.md.

Common Mistakes

Mistake	What happens	Fix
Using pipeline slug as GraphQL pipelineID	Mutation fails with "not found" error	Query the pipeline first to get its id (base64-encoded GraphQL node ID), then use that in mutations
Missing Content-Type: application/json on POST requests	422 error or empty response body	Always include -H "Content-Type: application/json" for POST/PUT/PATCH requests
Not following Link header pagination	Only get first 30 results, missing data	Parse the Link header for rel="next" and loop until no next link exists
Using per_page above 100	Silently capped at 100, appears to work but data is incomplete	Set per_page=100 maximum and paginate for larger result sets
Ignoring 429 rate limit responses	Subsequent requests fail or get blocked	Read the Retry-After header and wait before retrying
Comparing webhook signatures with == instead of timing-safe comparison	Vulnerable to timing attacks	Use crypto.timingSafeEqual (Node.js) or hmac.compare_digest (Python)
Sending env as a string instead of object in build creation	422 error	env must be a JSON object: {"KEY": "value"}, not "KEY=value"
Using REST API for cluster/queue management	404 — endpoints do not exist	Use the GraphQL API for cluster and queue operations (clusterQueueCreate, etc.)

Additional Resources

• references/graphql-reference.md — Full GraphQL query/mutation examples, pagination, introspection
• references/webhooks.md — Webhook creation, payload structure, signature verification, handler example
• references/patterns.md — Common API usage patterns: fetching failed builds, build success rates, triggering downstream pipelines

Further Reading

• Buildkite Docs for LLMs
• Buildkite REST API reference
• Buildkite GraphQL API documentation
• Buildkite GraphQL Explorer
• Buildkite Webhooks guide
• API authentication and token management