Sound Transit

Sound Transit is a regional transit authority serving the Seattle-Puget Sound area of Washington State, operating light rail, commuter rail, and express bus services. The Sound Transit Open Transit Data (OTD) program provides GTFS static and real-time data feeds, OneBusAway API access, and GTFS-RT service alerts for transit application developers and researchers.

Sound Transit publishes 7 APIs on the APIs.io network, including Agencies API, Arrivals And Departures API, Routes API, and 4 more. Tagged areas include Transit, Transportation, GTFS, Real-Time, and Public Transit.

The Sound Transit catalog on APIs.io includes 1 JSON-LD context and 2 Spectral governance rulesets.

Sound Transit’s developer surface includes developer portal, support, and 14 more developer resources.

🌐 Visit website 📡 Source on GitHub

44.1/100 developing ▬ flat Agent 22/100 agent aware Full breakdown ↓
scored 2026-07-28 · rubric v0.6

AccessFreemium

7 APIs

TransitTransportationGTFSReal-TimePublic TransitGovernmentSeattle

Kin Score

Kin Score How this is scored →
scored 2026-07-28 · rubric v0.6

Composite quality — 44.1/100 · developing

Contract Quality 15.2 / 25

Developer Ergonomics 2.6 / 20

Commercial Clarity 10.0 / 20

Operational Transparency 4.8 / 13

Governance 7.0 / 12

Discoverability 7.4 / 10

Agent readiness — 22/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/sound-transit: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 7

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

Rate Limits 1

Documented rate limits and quota policies.

Sound Transit Rate Limits

5 limits

RATE LIMITS

FinOps 1

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

JSON Schema 2

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

Examples 1

Example request and response payloads for these APIs.

AGENTIC

Resources

Get Started 1

Portal, sign-up, and the first successful call

Portal

Portal

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

API Key Request

API Key Request

Operate 1

Status, limits, changes, and where to get help

Support

Support

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

Trip Planner

Trip Planner

Company 2

The organization behind the API

LinkedIn

Website

Website

Other 6

Properties that don't map to a standard resource type

GTFS Static Feeds

GTFS Static Feeds

GTFS-RT Service Alerts (Protocol Buffers)

GTFS-RT Service Alerts (Protocol Buffers)

GTFS-RT Service Alerts (JSON)

GTFS-RT Service Alerts (JSON)

Transitland Feed

Transitland Feed

OneBusAway

OneBusAway

Real-Time Coverage

Real-Time Coverage

Source (apis.yml)

aid: sound-transit
name: Sound Transit
description: Sound Transit is a regional transit authority serving the Seattle-Puget Sound area of Washington State, operating
  light rail, commuter rail, and express bus services. The Sound Transit Open Transit Data (OTD) program provides GTFS static
  and real-time data feeds, OneBusAway API access, and GTFS-RT service alerts for transit application developers and researchers.
type: Index
accessModel:
  pricing: freemium
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Freemium
  confidence: medium
  source:
  - plans
  generated: '2026-07-22'
  method: derived
position: Consumer
access: 3rd-Party
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/sound-transit.png
tags:
- Transit
- Transportation
- GTFS
- Real-Time
- Public Transit
- Government
- Seattle
created: '2026-03-16'
modified: '2026-05-19'
url: https://raw.githubusercontent.com/api-evangelist/sound-transit/refs/heads/main/apis.yml
specificationVersion: '0.19'
apis:
- aid: sound-transit:sound-transit-agencies-api
  name: Sound Transit Agencies API
  description: Transit agency information and coverage
  humanURL: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
  baseURL: https://api.pugetsound.onebusaway.org/api/where
  tags:
  - Agencies
  properties:
  - type: OpenAPI
    url: openapi/sound-transit-agencies-api-openapi.yml
  - type: Documentation
    url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
  - type: Reference
    url: http://developer.onebusaway.org/
  - type: GTFS Downloads
    url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd/otd-downloads
- aid: sound-transit:sound-transit-arrivals-and-departures-api
  name: Sound Transit Arrivals And Departures API
  description: Real-time and scheduled arrival/departure information
  humanURL: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
  baseURL: https://api.pugetsound.onebusaway.org/api/where
  tags:
  - Arrivals And Departures
  properties:
  - type: OpenAPI
    url: openapi/sound-transit-arrivals-and-departures-api-openapi.yml
  - type: Documentation
    url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
  - type: Reference
    url: http://developer.onebusaway.org/
  - type: GTFS Downloads
    url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd/otd-downloads
- aid: sound-transit:sound-transit-routes-api
  name: Sound Transit Routes API
  description: Route definitions and schedules
  humanURL: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
  baseURL: https://api.pugetsound.onebusaway.org/api/where
  tags:
  - Routes
  properties:
  - type: OpenAPI
    url: openapi/sound-transit-routes-api-openapi.yml
  - type: Documentation
    url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
  - type: Reference
    url: http://developer.onebusaway.org/
  - type: GTFS Downloads
    url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd/otd-downloads
- aid: sound-transit:sound-transit-stops-api
  name: Sound Transit Stops API
  description: Stop locations and schedules
  humanURL: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
  baseURL: https://api.pugetsound.onebusaway.org/api/where
  tags:
  - Stops
  properties:
  - type: OpenAPI
    url: openapi/sound-transit-stops-api-openapi.yml
  - type: Documentation
    url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
  - type: Reference
    url: http://developer.onebusaway.org/
  - type: GTFS Downloads
    url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd/otd-downloads
- aid: sound-transit:sound-transit-system-api
  name: Sound Transit System API
  description: System utilities and configuration
  humanURL: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
  baseURL: https://api.pugetsound.onebusaway.org/api/where
  tags:
  - System
  properties:
  - type: OpenAPI
    url: openapi/sound-transit-system-api-openapi.yml
  - type: Documentation
    url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
  - type: Reference
    url: http://developer.onebusaway.org/
  - type: GTFS Downloads
    url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd/otd-downloads
- aid: sound-transit:sound-transit-trips-api
  name: Sound Transit Trips API
  description: Trip details and active vehicle positions
  humanURL: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
  baseURL: https://api.pugetsound.onebusaway.org/api/where
  tags:
  - Trips
  properties:
  - type: OpenAPI
    url: openapi/sound-transit-trips-api-openapi.yml
  - type: Documentation
    url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
  - type: Reference
    url: http://developer.onebusaway.org/
  - type: GTFS Downloads
    url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd/otd-downloads
- aid: sound-transit:sound-transit-vehicles-api
  name: Sound Transit Vehicles API
  description: Active vehicle locations and assignments
  humanURL: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
  baseURL: https://api.pugetsound.onebusaway.org/api/where
  tags:
  - Vehicles
  properties:
  - type: OpenAPI
    url: openapi/sound-transit-vehicles-api-openapi.yml
  - type: Documentation
    url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
  - type: Reference
    url: http://developer.onebusaway.org/
  - type: GTFS Downloads
    url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd/otd-downloads
common:
- type: AgenticAccess
  url: agentic-access/sound-transit-agentic-access.yml
- type: DomainSecurity
  url: security/sound-transit-domain-security.yml
- type: GitHubOrganization
  url: https://github.com/SoundTransit
- type: LinkedIn
  url: https://www.linkedin.com/company/sound-transit
- type: Portal
  url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
- type: Website
  url: https://www.soundtransit.org/
- type: GTFS Static Feeds
  url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd/otd-downloads
- type: GTFS-RT Service Alerts (Protocol Buffers)
  url: https://s3.amazonaws.com/st-service-alerts-prod/alerts.pb
- type: GTFS-RT Service Alerts (JSON)
  url: https://s3.amazonaws.com/st-service-alerts-prod/alerts_pb.json
- type: Transitland Feed
  url: https://www.transit.land/feeds/f-c23-soundtransit
- type: OneBusAway
  url: https://onebusaway.org/
- type: TermsOfService
  url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd/transit-data-terms-use
- type: API Key Request
  url: mailto:oba_api_key@soundtransit.org
- type: Support
  url: mailto:open_transit_data@soundtransit.org
- type: Trip Planner
  url: https://tripplanner.kingcounty.gov/
- type: Real-Time Coverage
  url: https://www.soundtransit.org/help-contacts/business-information/open-transit-data-otd
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

Sound Transit

APIs 7

Open Collections 1

Pricing Plans 1