Steel Sessions API

openapi: 3.0.1
info:
  title: Steel Files Sessions API
  description: Steel is the open-source browser API for AI agents and apps. The Steel Cloud REST API launches and manages cloud browser sessions, runs stateless quick actions (scrape, screenshot, pdf, search), and exposes a live session viewer. Long-running automation connects to the per-session Chrome DevTools Protocol (CDP) WebSocket returned as `websocketUrl`, which is driven with Playwright, Puppeteer, or Selenium. The same surface is available self-hosted (Apache-2.0) from the steel-browser server, where the default base path is http://localhost:3000/v1.
  termsOfService: https://steel.dev/terms-of-service
  contact:
    name: Steel Support
    url: https://docs.steel.dev
  license:
    name: Apache 2.0
    url: https://github.com/steel-dev/steel-browser/blob/main/LICENSE
  version: '1.0'
servers:
- url: https://api.steel.dev/v1
  description: Steel Cloud
- url: http://localhost:3000/v1
  description: Self-hosted steel-browser
security:
- SteelApiKey: []
tags:
- name: Sessions
  description: Launch, inspect, and release cloud browser sessions.
paths:
  /sessions:
    post:
      operationId: createSession
      tags:
      - Sessions
      summary: Create a browser session
      description: Launch a new cloud browser session with optional proxy, fingerprint, dimensions, timezone, ad-blocking, and bandwidth options. Returns the session details including the `websocketUrl` (CDP) used to connect Playwright/Puppeteer over CDP, plus the live session viewer URLs.
      requestBody:
        required: false
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/CreateSession'
      responses:
        '200':
          description: Session created
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SessionDetails'
    get:
      operationId: listSessions
      tags:
      - Sessions
      summary: List sessions
      description: Returns all sessions for the authenticated account.
      responses:
        '200':
          description: A list of sessions
          content:
            application/json:
              schema:
                type: object
                properties:
                  sessions:
                    type: array
                    items:
                      $ref: '#/components/schemas/SessionDetails'
  /sessions/{sessionId}:
    get:
      operationId: getSession
      tags:
      - Sessions
      summary: Get session details
      parameters:
      - $ref: '#/components/parameters/SessionId'
      responses:
        '200':
          description: Session details
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SessionDetails'
  /sessions/{sessionId}/context:
    get:
      operationId: getSessionContext
      tags:
      - Sessions
      summary: Get session context
      description: Returns the browser context (cookies, localStorage, sessionStorage, IndexedDB) captured for the session, suitable for persisting and replaying authenticated state.
      parameters:
      - $ref: '#/components/parameters/SessionId'
      responses:
        '200':
          description: Session context
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SessionContext'
  /sessions/{sessionId}/live-details:
    get:
      operationId: getSessionLiveDetails
      tags:
      - Sessions
      summary: Get session live details
      description: Returns the live session viewer URLs, the CDP `websocketUrl`, the list of open pages/tabs, and the current browser state.
      parameters:
      - $ref: '#/components/parameters/SessionId'
      responses:
        '200':
          description: Live session details
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SessionLiveDetails'
  /sessions/{sessionId}/release:
    post:
      operationId: releaseSession
      tags:
      - Sessions
      summary: Release a session
      description: Releases (ends) a single browser session and frees its resources.
      parameters:
      - $ref: '#/components/parameters/SessionId'
      responses:
        '200':
          description: Session released
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ReleaseSession'
  /sessions/release:
    post:
      operationId: releaseSessions
      tags:
      - Sessions
      summary: Release all sessions
      description: Releases all active browser sessions for the account.
      responses:
        '200':
          description: Sessions released
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ReleaseSession'
components:
  schemas:
    SessionDetails:
      type: object
      required:
      - id
      - createdAt
      - status
      - websocketUrl
      properties:
        id:
          type: string
          format: uuid
        createdAt:
          type: string
          format: date-time
        status:
          type: string
          enum:
          - idle
          - live
          - released
          - failed
        duration:
          type: integer
          description: Duration of the session in milliseconds.
        eventCount:
          type: integer
        timeout:
          type: integer
          description: Session timeout in milliseconds.
        creditsUsed:
          type: integer
          description: Credits consumed by the session.
        websocketUrl:
          type: string
          description: CDP WebSocket URL (wss://) for the session. Connect with Playwright/Puppeteer via connect_over_cdp / connectOverCDP.
        debugUrl:
          type: string
          description: URL for viewing the live browser instance.
        debuggerUrl:
          type: string
          description: URL for debugging the session.
        sessionViewerUrl:
          type: string
          description: Live session viewer URL.
        dimensions:
          $ref: '#/components/schemas/Dimensions'
        userAgent:
          type: string
        proxy:
          type: string
        proxyTxBytes:
          type: integer
        proxyRxBytes:
          type: integer
        solveCaptcha:
          type: boolean
        isSelenium:
          type: boolean
    SessionContext:
      type: object
      description: Captured browser state for the session.
      properties:
        cookies:
          type: array
          items:
            type: object
            additionalProperties: true
        localStorage:
          type: object
          additionalProperties: true
        sessionStorage:
          type: object
          additionalProperties: true
        indexedDB:
          type: object
          additionalProperties: true
    CreateSession:
      type: object
      description: Options for launching a browser session.
      properties:
        sessionId:
          type: string
          format: uuid
          description: Optional client-supplied session identifier.
        proxyUrl:
          type: string
          description: Proxy URL to use for the session.
        userAgent:
          type: string
          description: User agent string to use for the session.
        sessionContext:
          $ref: '#/components/schemas/SessionContext'
        blockAds:
          type: boolean
          description: Block ads in the session.
        solveCaptcha:
          type: boolean
          description: Enable automatic CAPTCHA solving.
        optimizeBandwidth:
          description: Enable bandwidth optimizations. `true` enables all flags; an object allows granular control over blocked resource types and hosts.
          oneOf:
          - type: boolean
          - type: object
            properties:
              blockImages:
                type: boolean
              blockMedia:
                type: boolean
              blockStylesheets:
                type: boolean
              blockHosts:
                type: array
                items:
                  type: string
              blockUrlPatterns:
                type: array
                items:
                  type: string
        skipFingerprintInjection:
          type: boolean
          description: Skip fingerprint injection for this session.
        deviceConfig:
          type: object
          properties:
            device:
              type: string
              enum:
              - desktop
              - mobile
              default: desktop
        fullscreen:
          type: boolean
          description: Launch the browser in fullscreen mode with no Chrome UI.
        extensions:
          type: array
          items:
            type: string
          description: Browser extensions to load.
        persist:
          type: boolean
          description: Persist the session for later resumption.
        timezone:
          type: string
          description: Timezone to use for the session.
        dimensions:
          $ref: '#/components/schemas/Dimensions'
        credentials:
          type: object
          description: Configuration for autofilled session credentials.
          properties:
            autoSubmit:
              type: boolean
            blurFields:
              type: boolean
            exactOrigin:
              type: boolean
        isSelenium:
          type: boolean
          description: Indicates if the session is driven over Selenium.
    Dimensions:
      type: object
      properties:
        width:
          type: integer
        height:
          type: integer
    SessionLiveDetails:
      type: object
      properties:
        sessionViewerUrl:
          type: string
        sessionViewerFullscreenUrl:
          type: string
        websocketUrl:
          type: string
          description: CDP WebSocket URL for the session.
        pages:
          type: array
          items:
            type: object
            properties:
              id:
                type: string
              url:
                type: string
              title:
                type: string
              favicon:
                type: string
                nullable: true
        browserState:
          type: object
          properties:
            status:
              type: string
              enum:
              - idle
              - live
              - released
              - failed
            userAgent:
              type: string
            browserVersion:
              type: string
            initialDimensions:
              $ref: '#/components/schemas/Dimensions'
            pageCount:
              type: integer
    ReleaseSession:
      allOf:
      - $ref: '#/components/schemas/SessionDetails'
      - type: object
        properties:
          success:
            type: boolean
  parameters:
    SessionId:
      name: sessionId
      in: path
      required: true
      description: Unique identifier of the session.
      schema:
        type: string
        format: uuid
  securitySchemes:
    SteelApiKey:
      type: apiKey
      in: header
      name: Steel-Api-Key
      description: API key issued from app.steel.dev. Pass it in the `Steel-Api-Key` request header. Self-hosted instances may run without auth.