Transit Service Alerts API

openapi: 3.0.3
info:
  title: Transit Locations Service Alerts API
  description: 'The Transit API delivers real-time public transit data - nearby routes and stops, stop departures, route details, multimodal trip planning, and service alerts - across 1,100+ cities in 37 countries, plus shared-mobility availability for bikes, scooters, and carshare. The API is publicly documented at https://api-doc.transitapp.com/ but access is key-gated: developers request an access key (free tier of 5 requests/minute and 1,500 requests/month) via Transit''s request form, and higher volumes are arranged with the partnerships team.


    Requests are made against https://external.transitapp.com/v3 and authenticated with an `apiKey` request header. An `Accept-Language` header selects the response language.


    Grounding note: the `apiKey` header, the `https://external.transitapp.com/v3` base URL, and the `GET /public/nearby_stops` endpoint (with `lat`, `lon`, and `max_distance` parameters) are confirmed from Transit''s public documentation and working integrations. The remaining endpoints (`nearby_routes`, `stop_departures`, `route_details`, `otp/plan`, `service_alerts`, `available_networks`) and their request/response shapes are modeled honestly from Transit''s documented v3 API surface, GTFS / GTFS-realtime conventions, and Transit''s public capability descriptions; they are marked with `x-modeled: true`. Confirm exact field names against the live docs once an access key is issued.'
  version: '3.0'
  contact:
    name: Transit Partnerships
    url: https://transitapp.com/partners/apis
    email: partners@transit.app
  x-logo:
    url: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
servers:
- url: https://external.transitapp.com/v3
  description: Transit public API v3
security:
- apiKeyAuth: []
tags:
- name: Service Alerts
  description: Service alerts and disruptions for routes, stops, and networks.
paths:
  /public/service_alerts:
    get:
      operationId: getServiceAlerts
      tags:
      - Service Alerts
      summary: Get service alerts
      description: Returns service alerts and disruptions - delays, detours, elevator outages, and cancellations - scoped to a route, stop, or network, following the GTFS-realtime service-alert model.
      x-modeled: true
      parameters:
      - name: global_route_id
        in: query
        required: false
        description: Filter alerts affecting a specific route.
        schema:
          type: string
      - name: global_stop_id
        in: query
        required: false
        description: Filter alerts affecting a specific stop.
        schema:
          type: string
      - name: network_id
        in: query
        required: false
        description: Filter alerts affecting a specific transit network/agency.
        schema:
          type: string
      - name: Accept-Language
        in: header
        required: false
        description: Preferred response language (BCP 47).
        schema:
          type: string
          example: en
      responses:
        '200':
          description: Matching service alerts.
          content:
            application/json:
              schema:
                type: object
                properties:
                  alerts:
                    type: array
                    items:
                      $ref: '#/components/schemas/ServiceAlert'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '429':
          $ref: '#/components/responses/RateLimited'
components:
  responses:
    Unauthorized:
      description: Missing or invalid API key.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    RateLimited:
      description: Rate limit exceeded (free tier is 5 requests/minute, 1,500/month).
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  schemas:
    ServiceAlert:
      type: object
      properties:
        alert_id:
          type: string
          example: stm-2026-0701-747
        cause:
          type: string
          description: GTFS-realtime alert cause.
          example: CONSTRUCTION
        effect:
          type: string
          description: GTFS-realtime alert effect.
          example: DETOUR
        header_text:
          type: string
          example: Route 747 detour
        description_text:
          type: string
          example: The 747 is detoured due to construction on René-Lévesque.
        severity:
          type: string
          example: WARNING
        active_period_start:
          type: integer
          description: Unix epoch seconds the alert becomes active.
        active_period_end:
          type: integer
          description: Unix epoch seconds the alert ends.
        affected_global_route_ids:
          type: array
          items:
            type: string
    Error:
      type: object
      properties:
        status:
          type: integer
          example: 401
        message:
          type: string
          example: Invalid API key.
  securitySchemes:
    apiKeyAuth:
      type: apiKey
      in: header
      name: apiKey
      description: Transit access key requested via Transit's API request form. Sent as the `apiKey` request header on every call.